"Chemistry / Elements" Essays

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Evolution of Chemistry to the View Paper

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org, 2013). In following tests, it was found to cause the flame to burn more intensely and to keep the mouse alive longer (acs.org, 2013).

It's also vital to bear in mind that Priestly was a pneumatic chemist; there were many pneumatic chemists during this period as the result of the work of Stephen Hales, the man who had created… [read more]


Chemistry of Living Things View Paper

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Chemistry of Living Things

Basic chemistry dictates that matter refers to anything which occupies space and has mass. Elements are the smallest form of matter which cannot be broken down further to a simpler form. Examples are aluminum and iron. An atom is the smallest functional unit of matter that can take part in a chemical reaction and they are… [read more]


Physical Chemistry Notes Website: Pomona University "Moldata:" View Paper

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Physical Chemistry Notes

Website: Pomona University "MolData:" Physical Chemistry Resources

No hard data contained on this website, but links provided to any different databases and tables with an abundance of technical information pertaining to atoms and physical chemistry

Contains links to information on spectroscopic, nuclear, and atomic data, as well as tables of chemical and physical constants, as well as information on the physical and chemical propertied of many compounds and substances, including historical information regarding the discovery of many elements and other substances and their uses

Contents of the site provide a cursory overview of the wide range of topics that fall under physical chemistry, and shows the common link between them as being the atomic/molecular-level reactions and changes that take place to allow larger observed reactions

Book: The World of Physical Chemistry by Keith James Laidler

Provide more of an overview of many physical chemistry topics than the website, and less pure data

Discussions of physical chemistry facts provides deeper insights into the uses and applications of physical chemistry, as well as the processes of discovery that have led to the advancements of physical chemistry and its identification as a scientific discipline altogether

Different chapters/sections devoted to the various disciplines within physical chemistry

Provides both a broad overview of many physical chemistry concepts and applications and specific information regarding many of the different branches within physical chemistry

Stresses the necessity of understanding physical chemistry concepts for a true understanding of physics, and explains the application of physics to the movements and interactions of atoms, molecules, and sub-atomic particles in an easy-to-follow manner

News Article: "Nanotube Structures Could Improve Electric Motors" from Science Daily

Provides information on one groundbreaking new application for the science of physical chemistry, which also illustrates the fine line between physics and chemistry that occurs in the science

New carbon nanotubes have been developed that exhibit a high elasticity and durability, as well as a high conductivity of heat and electricity, reflecting the inseparability of physical and chemical properties of a substance, especially at the atomic level

These nanotubes have been tested as brush contacts to replace the carbon/copper brush contacts used in many electrical switches, and show a ninety-percent reduction in energy loss

This article shows the ongoing practical applications of this particular scientific discipline

Physical Chemistry

Of all the many fields and topics in the broad ranging science of chemistry, the one that interests me the most is physical chemistry. In reality, physical chemistry is also a broad ranging discipline, covering such diverse areas as quantum mechanics, nuclear chemistry, and thermodynamics, among many others (MolData). These topics all deal with matter at the very smallest level, which is one of the most exciting frontiers of physics, chemistry, and science in general. Despite the recent setback at the Large Hadron Collider at CERN, there is still a belief in the scientific community that we may soon detect the elusive Higgs boson particle. This particle could help explain the origins of the universe, and even… [read more]


Nuclear Chemistry View Paper

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¶ … nuclear chemistry, including the history of its development, a brief examination of certain key reaction that are used and examined in the field, and an assessment of nuclear chemistry's value to chemistry as a whole. Nuclear chemistry deals with the smallest particles involved in chemical reactions, what are known as alpha and beta particles. From the early discovery of radiation and the identification of these particles in the late nineteenth century to the current era of nuclear energy and increased understandings of stars, nuclear chemistry grew up quite rapidly. Uranium reactions such as those that take place in basic nuclear reactors are described, and the importance of nuclear chemistry in the future is also detailed.

Introduction

There are many different branches of chemistry, all of which yield exciting academic as well as practical advances and results. Ultimately, however, none of the other branches of chemistry would make much sense without the findings of nuclear chemistry. This does not mean that nuclear chemistry emerged as a distinct branch of chemistry ahead of the others, or that other areas of chemistry branched off from nuclear chemistry, but simply that nuclear chemistry deals with some of the most fundamental aspects of chemical reactions, without which there truly wouldn't be any matter or energy with which to drive the chemical reactions and properties studied by chemists in other areas. Though nuclear chemistry's applications are fairly specific, its knowledge informs the smallest level of the world of matter.

Nuclear Chemistry

Nuclear chemistry essentially started with the discovery of radioactivity in the tail end of the nineteenth century (Bodner, 211; Duke, 2011). Researchers like William Conrad Roentgen, Marie and Pierre Curie, and Ernest Rutherford (along with others) observed that metals and some salts containing some of the heavier known (and discovered) elements emitted very small particles at very high energies (Duke, 2011; Carpi, 2003). While typical chemical reactions occur with the valence electrons of atoms, leaving the atoms themselves fundamentally unchanged but for the gain, loss, or sharing of electrons, in 1896 Henri Becquerel link observed radiation to potential changes in uranium's nucleus, and the field of nuclear chemistry was then thrust rapidly from infancy to adolescence (Carpi, 2003).

Today, there are four identified aspects or specific areas of inquiry within the larger field of nuclear chemistry: the chemical and physical properties of radioactive elements, the nuclear properties of these elements and their reactions, large-scale processes that involve nuclear reactions, and measurement techniques based on nuclear phenomena (Loveland et al., 2006). This might not make it immediately clear why nuclear chemistry is so fundamental to other branches of chemistry. Yet when it is considered that ultimately all matter and energy in the world is sourced from nuclear reactions -- theoretically beginning with the Big Bang and continuing with the nuclear reactions that power the Sun and other stars -- this connection and fundamental nature becomes much more clear (Duke, 2011).

The basic nuclear reactions that lead to the emission of radioactive particles are still… [read more]


Symmetry in Inorganic Chemistry Molecules View Paper

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The overall molecule responds to symmetry operations in a manner that is captured by the behavior of the particular group to which the molecule belongs, individual atoms, bonds, atomic orbitals and any other component of the overall molecule may respond to symmetry operations in a variety of ways (Avetisov and Goldanskii). Therefore, there is a subclassification system associated with each point group to allow classification of the behavior or various submolecular parts of a molecule. All of the ways in which a particular bond, atom or set of atoms respond to a given set of symmetry operations are represented by a set of "irreducible representations," with their own cryptic labeling system and a list of characters, which can be found in character tables, the principle tool of group theory. The characters of a given irreducible representation in some more simple point groups behaves in the same way as the parts of the molecule that are said to belong to this irreducible representation.

Any object associated with a molecule can be labeled with one or more of these irreducible representation labels for purposes of classification (Avetisov and Goldanskii). For example, the water molecule, confined to the yz plane as is the modern convention, and oriented so that the z-axis bisects the molecule. The combination of the two hydrogen atoms of water, as an "object," can be considered with respect to the symmetry operations of the C2v point group. Rotation by 180 degrees about the principle axis leaves the hydrogen atoms in an indistinguishable position, as does reflection through either of its mirror planes. Therefore, the combination of two hydrogen atoms of water is said to behave as the "A1 representation" of the C2v point group. Other objects that transform in the same way are the in-phase combination of the 1s orbitals on each atom, the pair of O-H bonds, the symmetric stretching of the two O-H bonds, and each of the 1s, 2s, and 2pz orbitals on the oxygen. The characters for this irreducible representation in C2v are all +1, reflecting no change with respect to each element. In contrast, the py orbital on oxygen, and the antisymmetric stretching motion of the two O-H bonds are said to "transform as B2." The implications of this label are best understood through the characters for the B2 representation. These are +1, which reflect through the plane containing the molecule and E, or do nothing to the molecule, corresponding to operations that leave these objects unchanged after the operation. In contrast, the character to reflect through the plane perpendicular to the molecular plane and C2 or rotate by 180 degrees about the principle axis is -1, reflecting a change in sign of the wave function on such reflection or rotation, or a reversal in the direction of the stretching motion of each bond in the antisymmetric stretch.

Identifying the irreducible representation associated with a given bond, atom or sets thereof, is of great value for three reasons. First, it is a convenient way of… [read more]


Chemistry at Work. Every Facet View Paper

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Of CO and not to the first R. Or Ar (Morrison & Boyd, 1983, pp. 734-737).

Carboxylic acids are also important. Vinegar, used in cooking, is the simplest organic acid. Its formula is CH3COOH -- acetic acid. The functional group COOH is the carboxylic acid group. It combines a carbonyl group (C=O) with the OH group attached to the carbonyl carbon atom (Morrison & Boyd, 1983, p. 755).

Esters are derived from carboxylic acids. The H. In the OH part of the acid (COOH) is replaced by an R. Or Ar group. The generic formula for esters is therefore, R (Ar)-COO-R'(Ar'). The prime (') indicates that the R. groups or Ar groups need not be similar (Morrison & Boyd, 1983, p. 830).

The last functional group is a derivative of ammonia NH3 that is used in smelling salts and glass cleaning solutions. An alkyl group or aryl group replaces one of the hydrogen atoms in ammonia. The resultant compound is an amine. Methylamine CH3NH2 is the simplest example (Morrison & Boyd, 1983, p. 878).

Thus Chemistry helps life -- intrinsically and extrinsically. Chemical processes are observed at macroscopic levels and microscopic levels. They are man made or have evolved with nature. The salient point to remember in the formation of compounds (everything else flows from there) that drives chemical processes is the need to complete the valence or the atomic shell -- each element's inherent instability. Inorganic and organic chemistry is the results of variable approaches to solving the instability. This then results in the formation of stable compounds the world we live in and the universe at large need to survive.

References

Hachiya, M. (1945). The Hiroshima/Nagasaki Legacy. Retrieved January 26, 2003, at http://nuketesting.enviroweb.org/hew/Japan/Hirosh.html

Aquatext Online (2000). Composition of Air. Retrieved January 26, 2003, at http://www.aquatext.com/tables/air.htm

WebElements (2003). WebElementsTM Periodic table (professional edition). Retrieved January 26, 2003, at http://www.webelements.com/

Lee, M. (1999) Covalent Bonds. Retrieved January 26, 2003, at http://207.10.97.102/chemzone/lessons/03bonding/mleebonding/covalent_bonds.htm

Lee, M. (1999) Ionic Bonds. Retrieved January 26, 2003, at http://207.10.97.102/chemzone/lessons/03bonding/mleebonding/ionic_bonds.htm

Morris, R.T. And Boyd, N.B. (1983). Organic Chemistry. 4th Ed. Boston: Allyn and Bacon, Inc.… [read more]


Garage Chemistry and Do-It-Yourself Science Labs View Paper

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Garage Chemistry and Do-It-Yourself Science Labs

It is a litigious world humans have created, and the lawyers rule it. The history of almost all commercially available products can be traced from a distant heyday of free thought and free will -- a time when conservatives argued for smaller government and rugged individualism meant something in this country -- through a… [read more]


Mercury Is Element Number 80 and Is View Paper

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Mercury is element number 80 and is symbolized Hg. It appears on the periodic table in the far-right column of transition metals, right next to the poor metals. With only two electrons in its outer shell, it is incredibly reactive and volatile. There are also several radioactive isotopes of mercury, several of which are highly unstable: HG 197 has a half-life that is measured in hours, and HG 206 has a half life of less than nine minutes. The most unique thing about mercury is that it is the only metal that is liquid at room temperature. it's melting -- or freezing -- point is a chilly -38.9 degrees Celsius (roughly -38.02 degrees Fahrenheit). It is also a very poor conductor of heat, which is one of the reasons it is so useful in thermometers -- it expands and contracts over a wide range in response to temperature changes.

Mercury is also very good at conducting electricity, and is often used in batteries. It is also very reactive with other metals, and can be used to make amalgams (alloys) with other metals. It is so…… [read more]


Chemistry and Photosynthesis Chemically Speaking, Photosynthesis Is View Paper

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chemistry and PHOTOSYNTHESIS

Chemically speaking, photosynthesis is the utilization of sunlight by plants for the conversion of carbon dioxide into organic matter. In green plants like trees, shrubs, flowers and conifers, the overall chemical reaction may be represented by the balanced equation CO2 +H2O{CH2O}+O2 in which the newly-formed organic matter is represented by CH2O, a generalized formula for a carbohydrate. The overall process by which green plants convert sunlight to food can be expressed with the equation 6H2O+6CO2C6H12O6+6O2 which translates to "six molecules of water plus six molecules of carbon dioxide produce one molecule of sugar plus six molecules of oxygen" (Farabee, Internet).

The importance of this rather simple process lies in its conversion of energy from radiant (i.e., sunlight) into chemical form (i.e., sugar). Depending slightly on the specific kind of carbohydrate formed, the amount of energy transformed is about "112 kcal per mole of CO2 fixed," and because of this large energy requirement, non-photochemical schemes for fixing CO2 as organic matter is very rare. Thus, the chemical energy which all green plants store by photosynthesis provides the total energy requirement for the plant, including the energy required for the synthesis of a wide variety of other organic substances (Gregory, 67).

All green plants receive their carbon dioxide (CO2) directly from the Earth's atmosphere and under conditions of low light, the rate of photosynthesis is often separate of the CO2 content, but under strong sunlight, the rate is dependent upon "the carbon dioxide partial pressure at low CO2 and reaches a limiting value at high CO2. The average CO2 content of surface air, usually about.03% (considering the current effects of global warming and climate change) is not quite enough for most land plants. Aquatic plants, however, derive their CO2 from dissolved gases in the water.

Overall, the normal primary photosynthetically-produced carbohydrate is known as phosphoglyceraldehyde, being "the phosphate ester of a 3-carbon sugar" molecule (Silverstein, 178). The synthesis of hexoses, a sugar with six carbon atoms in its molecules, and storage polysaccharides, a polymer of ten or more monosaccharides joined by glycosidic links, as well as the formation of fats, proteins and other organic substances during periods of photosynthetic activity, are attributed to a number of secondary processes, far too complicated to explore here. However, our current understanding of the pathway of carbon in photosynthesis comes mainly from "labeling experiments with C14 enriched CO2 (Silverstein, 179).

Generally speaking, the photosynthetic carbon cycle is made up of reactions concerned with the function and re-creation of the actual acceptor molecule reacting with carbon dioxide, assimilation and the photochemical reduction. These CO2 acceptors (5-carbon ribulose diphosphate) is created by condensation and hydrolises, while part of the primary carbohydrates go directly to stored sugars or starch. Through several other complicated chemical processes, the end-product is oxygen which is then released into the atmosphere for use by air-breathing animals.

The chemical process of photosynthesis is made up of light and dark reactions which can be summarized as CO2+4H2O{CH2O}+3H2O+O2 (Bacon, 214). Under very weak sunlight,… [read more]


Metallic Element Erbium Erbium: The Metal and View Paper

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Metallic Element Erbium

Erbium: The Metal and Its Uses

This paper explores the metallic element erbium, which prior to the use of fiber optic communication systems and "Wi Fi" communications received little attention. Considered a rare element, erbium while typically gray in color also contains pink compounds, making it useful as an addition to glass or porcelain products aesthetically. For one to appreciate the real value erbium has to offer one must understand its history, physical properties and availability. The paper begins by a discussion of the history of erbium followed by an overview of its physical properties, uses and functions.

Who Discovered/When

Erbium is one of many elements listed in the periodic table, a metallic chemical element specifically (Columbia 15785). Symbolized by the abbreviation Er, most credit the discovery of this element to a scientist named Carl G. Mosander, who although did not isolate the element, located it and separated it from "three oxide fractions" (Columbia 15785). It was not until 1934 that pure erbium was isolated from it's fractions by other scientists (Columbia 15785) allowing for greater exploration into its uses for commercial purposes.

Physical Properties and Locations

The physical properties of Erbium are as follows: (1) wt. = 167.26; (2) melting point at 1,529 degrees Celsius; (3) boiling point at 2,863 degrees Celsius; and (4) "sp.gr. 9.05" when at 25 degrees Celsius (Columbia, 15785). The element has a valence of +3, and the element itself looks silver in color, giving off a soft and glossy look and appeal. The metallic element is also very malleable or soft in nature.

In its purest form erbium is not a stand alone element; rather it contains 6 isotopes (stable) and 10 radioactive ones (Columbia 15785). Within the periodic table of elements scientists categorize or group Er in class IIIb and as a member of the lanthanide series (Columbia 15785). This series of elements are considered "rare" and includes all elements containing atomic numbers "58-71" with erbium ranked at 68 (Columbia, 27273).

Typically erbium is found with other very rare metallic elements, often located in Sweden (Columbia 15785). In its natural state erbium typically is located while bound within "mozanite sand ores" (Wiki 1). Most erbium comes from minerals including euxenite, xenotime and in the last decade or so from clays located within southern China (Wiki 1; Columbia 15785). Many of the countries that now prepare erbium for commercial purposes are in fact, located in China.

Companies Involved in Preparation and Sale

The use of erbium lasers is becoming increasingly popular as many companies utilize this technology to enhance appearance and for skin resurfacing, in part due to the advent of erbium-doped fiber amplifiers, described below. Examples of companies that prepare the compound include Jiangsu Hongyuan Textile Machinery Co. Ltd., located at 11 Liagxi Road, Wuxi Jiangsu Province, China (Alibaba).

Another company not surprisingly located in China includes the Zhejiang Ante Meter Co., Ltd., located in the Ante Industrial Park, Wenxi, Qungtian, and Lishui City, Zhejiang, China (Alibaba).

Other companies including… [read more]


Green Chemistry Lesson Plan View Paper

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Green Chemistry Lesson Plan

Green Chemistry - Lesson Plan

Lesson plan:

It's not easy being green: The 12 principles of green chemistry

Educational goal: To understand how the green principles of chemistry affect students' daily lives and the products they use

The 12 principles of green chemistry are extremely relevant in terms of the ways that they affect the industrial development of new products. The 12 principles counsel that it is advisable to avoid waste; to incorporate as many as possible of the materials involved in the production into the final product; that manufacturers should strive to create nontoxic synthetic products; that chemical products should be designed to realize their intended function while minimizing their toxicity; that there should be a minimization of auxiliary substances used in production; that the environmental and economic impact of the chemical product should be minimized; that raw materials should be renewable whenever possible; that unnecessary derivation from other sources should be minimized; that production should emphasize catalytic reagents to stoichiometric reagents; that products should be designed to degenerate so as not to add to the waste or toxicity in the environment; that products should be monitored so as not to become hazardous; and products should be designed to minimize the potential for accidents (12 principles of green chemistry, 2011, ACS).

Teacher background information: The standards from Massachusetts Science Curriculum Frameworks state that students in grades 6-8 should be able to:

Formulate a testable hypothesis using the scientific method and design and conduct a scientifically-valid experiment with variables that can be changed, controlled, and measured.

Select appropriate tools and technology for an experiment and make quantitative observations about an experiment.

Draw conclusions and present and explain data and findings using multiple representations (such as tables, graphs, mathematical and physical models, and demonstrations to the class using numbers as well as words) and use science and technology terminology.

"Offer explanations of procedures, and critique and revise them as necessary" (Massachusetts curriculum frameworks, 2011, Massachusetts Education).

Safety information: Most of the out-of-class work will…… [read more]


Proton and Carbon NMR View Paper

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Proton and Carbon NMR

In chemistry one of the most common issues is constant change. This is based on chemical properties continually transforming into different states. In some cases, these shifts are visible to naked eye. While at other times, they are visible only through specialized tools. When it comes to the use of proton and carbon, these changes are… [read more]


Abundant Elements That Occur in View Paper

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Carbohydrates are organic compounds composed of carbon, hydrogen, and oxygen, with a typical ratio of 1:2:1, respectively; they tend to be polar; they are broken down during cellular respiration; and they provide most of the body's energy. Proteins, also organic compounds, consist of hydrogen, oxygen, carbon, and nitrogen atoms; they include chains of amino acids, which in turn form strings of polypeptides; they are usually soluble in water, salt solutions, or in alcohol; they have a coiled structure; and they are the major structural and functional material of body cells. Lipids are fatty compounds made of carbon, hydrogen, and oxygen, with an abundance of carbon-hydrogen bonds; they are not water soluble; and their purpose is to store energy. Nucleic acids are complex organic compounds that store important information in cells; they contain phosphorous, carbon, oxygen, hydrogen, and nitrogen; and they are mildly acidic. DNA and RNA are the most important types…… [read more]


Integrated Science & Periodic Table View Paper

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Metals from the left side of the periodic table have the tendency of losing electrons in order to stabilize itself. Because the ionization energy from left to right increases, the lower the ionization energy, the easier it will be for these metals to lose their valance electrons, making it favorable for them to combine and react with elements from the right side of the periodic table (Chang 2010). These elements are the opposite of the left side elements. These ionization energies are much higher, therefore it is easier for them to gain an electron from another element to form a compound, than it is for these elements to give a valance electron up. These right-sided elements are called non-metals. However, these non-metals are further broken up into categories. Elements in group VII are called halides or salts because of their tendency to react with the elements from group I in order to form salt ionic compounds (Chang 2010). Examples of this include sodium fluoride (Na+ and F-) and sodium chloride (Na+ and Cl-) which is table salt. Noble gases, which are the elements in the final group, have complete valence shells, so they do not pair well with the left-sided elements, although they do belong to the non-metals group (Chang 2010). This is also due to their high ionization energies which make it impossible to break these elements apart or to give or take an electron.

Octets are formed when an atom has a full valence shell. That is, an element is more stable if the number of electrons surrounding the nucleus has a sum of eight (Chang 2010). This is what covalent bonds are all about. Nonmetals from the right side of the periodic table react with nonmetals from the same right side because these elements have extremely high ionization energies, therefore it is more efficient for the element to share an electron with another element from the same side instead of giving an electron or gaining an electron from the elements in the first group on the left side of the periodic table (Chang 2010). It takes a lot more energy than it does to just share the electrons. Because these elements need only one or two more electrons to fill up their valence shell, they combine and share the missing electron with each other. A perfect example of this is water. Hydrogen, which belongs to both the left side and the right side of the periodic table because of its similar characteristics with both types of elements, forms a covalent bond with oxygen to form the covalent molecule, H2O. Oxygen needs two more electrons to complete its shell and have an octet, so it shares the electron that hydrogen has. Because oxygen needs two more electrons, and hydrogen only has one, it needs another hydrogen atom to become a stable molecule. Another example is hydrogen sulfide (Chang…… [read more]


Philosophy of Chemistry the Work View Paper

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Chemistry has been originally viewed by the philosopher as having been reduced to mere physics thereby holding no interest fundamentally however, those misconceptions are presently being examined and reflected upon. Models and methodology of chemistry research are also being critically examined as well as is the realism in relation to chemistry and the scientific terms utilized. Molecular structure is also undergoing critical analysis and as indicated in the work of Scerri molecular structure is held as a mere metaphor with no objective reality at the quantum mechanical level. These are only some of the aspects of chemistry that are presently being questioned by philosopher and chemists alike in the search for meaning behind the philosophy of chemistry in today's science community.

Bibliography

Scerri, ER (1997) Philosophy of Chemistry -- A New Interdisciplinary Field?. Retrieved from: http://www.chem.ucla.edu/dept/Faculty/scerri/pdf/poc_=JCE_article.pdf

Hoffmann, R. The Same and Not the Same; Columbia University Press: New York, 1995. Knight, D. Ideas in Chemistry, Rutgers University Press: New Brunswick, NJ, 1992. Nye, M.J. From Chemical Philosophy to Theoretical Chemistry; University of California Press: Berkeley, 1993. Laszlo, P. La Parole des Choses; Collection Savoir-Science: Paris, 1993. Hoffmann, R.; Laszlo, P. Angew. Chem., Int. Ed. Engl. 1991, 30, 1 -- 16

Scerri, ER and McIntyre, L (2000) The Case for the Philosophy of Chemistry. Retrieved from: http://philsci-archive.pitt.edu/256/1/Case_for_poc.pdf

Schummer, J. (2006) Philosophy of Chemistry. in: Donald M. Borchert (ed.), Encyclopedia of Philosophy, Second Edition,…… [read more]


Inorganic Chemistry Linear Sp Carbon View Paper

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Additionally, when the polyenes are end-capped with organic or organometallic groups, the instability becomes likewise proportionately affected. It was cited from previous studies that shorter interchain distances are favorable for achieving stability, and the addition of bulky terminating groups do impact the molecular stability. Extending the carbon chains beyond the homologues presented by Hirsch et al. is considered to demonstrate… [read more]


Bonds and Compounds View Paper

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Chemical Bonds: Ionic and Covalent Bonding

A chemical bond is an attraction between atoms that lets chemical substances that contain two or more atoms. Two forms of chemical bonding are ionic bonding and covalent bonding. Additionally, ionic and covalent bonds can be combined to form mixtures and compounds.

Ionic and covalent bonds are formed through the bonding of two or more elements. An element is a pure substance composed of a single atom. There are currently 117 known elements with 94 elements occurring naturally and 22 artificial elements. The properties and names of all known elements can be found on the Periodic Table.

Ionic bonded and covalent bonded substances can be combined to create either a mixture or a compound. A mixture is a heterogeneous form of matter that is composed of variable proportions of molecules and atoms. The properties of a mixture include the variability of the composition that means that a mixture can be any combination of substances. In a mixture, the components that make up that mixture retain their individual characteristic properties and the components of said mixture are easily separated. Mixtures can be separated through various forms including dialysis, chromatography, and electrophoresis. In biochemistry, dialysis is the separation of molecules in a solution based on their differing rates of diffusion through a semi-permeable membrane. Chromatography is a separation method that is based on the differences in the partitioning behavior between a mobile phase and a stationary phase. Electrophoresis is the separation of substances based on the rate of movement of each component in a colloidal suspension when under the influence of an electric field.

Compounds are pure substances that are composed of two or more elements. Unlike a mixture, a compound is a homogeneous form a matter in which the elements are present in fixed proportions. Additionally, components that comprise a compound do not retain their individual properties and large inputs of energy are required to separate a compound into its separate components. Compounds are formed naturally to provide elemental stability; stability is determined by the number of electrons present in the outermost energy level of an atom.

Ionic bonds are formed when atoms link together due to the attraction of ions with opposing charges. In ionic bonding, electrons are completely transferred from one of the bonding atoms to another atom. These electrons are…… [read more]


Ionic and Covalent Bonds Chemical Bonds Are View Paper

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Ionic and Covalent Bonds

Chemical bonds are formed when there is an attraction between atoms that allows chemical substances containing more than two atoms form. The two forms of chemical bonding are ionic bonding and covalent bonding. Furthermore, ionic bonds and covalent bonds can be combined to form mixtures and compounds.

Ionic and covalent bonds form when two or more elements are bonded together. Elements are pure substances that are comprised of one atom. The elements can be found on the periodic table, arranged by their atomic number. There are 117 elements that have been discovered to date; 94 of these elements are found to be naturally occurring while the remaining 22 elements are artificial. Substances that are formed by ionic and covalent bonds can be further combined to form mixtures and/or compounds. A mixture is a heterogeneous form of matter composed of varying proportions of molecules and atoms. A mixture can be any combination of substances. These substances that comprise a mixture keep their individual and characteristic properties; these substances can be easily separated from the mixture. Separation of these substances can be achieved through dialysis, chromatography, or electrophoresis. Dialysis is the separation of molecules in a solution in which the molecules diffuse through a semi-permeable membrane. Chromatography separates molecules based upon differing partitioning behaviors that occur between a mobile and stationary phase. Electrophoresis separates substances based upon the rate of their movement in a colloidal suspension when introduced to an electric field (Decelles, 2001).

Compounds are pure substances that are made up of two or more elements. Whereas a mixture is a heterogeneous form of matter, a compound is a homogeneous form of matter where the elements are present in fixed proportions. The elements that make up a compound do not retain their individual properties and large amounts of energy are required to separate a compound into its separate parts. Compounds are naturally formed to provide elemental stability. This stability is dependent on the number of electrons found in the outermost energy level of an atom.

Ionic bonds are formed when atoms link together because of the attraction of ions that have opposing charges. Ionic bonding requires that electrons completely transfer from one of the bonding atoms to the other. Electrostatic forces allow for these electrons to be attracted to each other. When an atom loses an electron, this atom will reduce in size. Inversely, when an atom gains an electron, the receiving atom will grow in…… [read more]


Chemistry Based on the Fact View Paper

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To obtain a complete force map the microscope needed to be highly stable, both mechanically and thermally, to ensure that both the tip of the AFM and the molecule remained unaltered during the more than 20 hours of data acquisition." (IBM)

This is a key discovery because the atomic structure that is now available to all scientists can be considered to be the backbone of the atomic world. "Scanning probe techniques offer amazing potential for prototyping complex functional structures and for tailoring and studying their electronic and chemical properties on the atomic scale." (IBM)

The remarkable thing about this advance is that it comes just a few months after another astonishing discovery. "The team's current publication follows on the heels of another experiment published just two months ago in the June 12 issue of Science (Volume 324, Issue 5933, pp. 1428-1431) where IBM scientists measured the charge states of atoms using an AFM. These breakthroughs will open new possibilities for investigating how charge transmits through molecules or molecular networks." (IBM) Most people in the world will not have a clue what this combination of discoveries entail. What it translates into is completely new nanotechnology.

That is because, when scientists have a good grasp of the charge distribution at the atomic scale, they can translate that information into building even smaller, faster and completely energy-efficient computer components. These breakthroughs will literally make many of today's computer parts like processors and memory devices completely obsolete. Of course, IBM has a vision of an all IBM planet that is interconnected so the potential financial implications for the company could be significant. "Scientists have been striving to 'see' and manipulate atoms… [read more]


Avogadro Chemists Use Avogadro's Number on a View Paper

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Avogadro

Chemists use Avogadro's Number on a daily basis and it is therefore necessary to not only know and understand what the number signifies, but also to know who created it, why it was created, and of what use it is in today's chemical society.

The name "Avogadro's Number" is just an honorary name attached to the calculated value of the number of atoms, molecules, etc. In a gram mole of any chemical substance. Of course if we used some other mass unit for the mole such as "pound mole," the "number" would be different than 6.022 x 1023."(Furtsch)

The title honors Amedeo Avogadro, an eighteenth century scientist born in Turin, Italy on August 9, 1776. His family was comprised of successful lawyers, and he followed the family's tradition by graduating in ecclesiastical law.

Lorenzo Romano Amedeo Carlo Avogadro, known as Amedeo Avogadro, one of the many creative Italians that have enriched our lives, was born in 1776 - a memorable date hitherto for other reasons. Possibly of aristocratic descent, he was a lawyer until he decided to devote himself to one of his other interests: in his late twenties he was appointed to the first chair in mathematical physics in Italy, at L' Universita' di Torino." (Avogadro)

His interest in law never waned but was supplanted by his interest in natural science. This interest compelled him to attend private lessons in both mathematics and physics. Following and intense period of study, he wrote a hypothesis that contributed several facets to the science community.

Avogadro was the first to publish (in 1811) the idea that elements could exist as…… [read more]


Unaware That Most of Them View Paper

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These are accomplished by the chemical processes applied by the forensic scientists, techniques like employment of molecules such as nucleic acids and proteins.

Another event specific to the use of chemistry to provide evidence is explosion. It may occur deliberately or accidentally during domestic, commercial, criminal or terrorist cases. Identifying and tracing the capacity of materials from the explosive devices is essential to know the cause of the explosion.

The terrorist event in 1993 in the underground parking lot of the World Trade Center was an instance where chemistry helped in identifying the materials used. The bomb was created using various chemicals that was exploited to produce chain reaction. The investigators found out that a gel of urea nitrate was used when they analyzed the debris in the parking. A high level of urea and nitric acids were found.

The application of chemistry is very important in arson and explosives investigation. The proficiency in conducting chemical examination aid in the process of determining the causes and producing evidences through the scientific analysis and implementation of chemistry. Any material, debris, and residues in any investigation are important for chemical testing to build facts about a case. The role of chemistry and the duties of the forensic analyst go hand in aiding mysteries and unknown causes of a particular crime. It is not only in the resolution of a case that forensic chemistry plays a vital role. It also helps in reducing the potentiality of crime.

Tracing evidences with the application of various chemical examinations is a big factor that shows and provides elements of a particular crime. Without chemistry, many crimes would still have been unresolved today. As how chemistry is important in our daily tasks, it is of the same importance in many professions. We live in a world of various elements. Understanding and knowing their importance is an essential part in achieving many of our tasks. As in the investigation of crimes, the ability of having a good knowledge in the field of chemistry is one of the basic requirements to provide better service in the protection of every citizen and in exhibiting evidences of crimes.

Bibliography

Borer, Keith. Forensic Chemistry.

Keith Borer Consultants Limited. 22 March 2003. http://www.borer.demon.co.uk/chemistry.htm

The Role of Forensic Scientist in Detection of Crime. http://assampolice.com/art2.htm

BSC Forensic Science.

2002. University of Central Lancanshire. 22 March 2003. http://www.uclan.ac.uk/facs/science/forensic/courses/bscforensicscience.htm

Chemistry and BioChemistry.

Ohio University. 22 March 2003. http://main.chem.ohiou.edu/undergraduate/forensic.html#What

Forensic Chemistry. 21 March 2003. http://www.westchestergov.com/labsresearch/labs/forensicandtox/forensic/Chemistry/Forchemmaindr.htm… [read more]


Chemistry Problems There Is a Wealth of View Paper

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Chemistry Problems

There is a wealth of information that can be provided in the formatting of discussing various compounds, like that of NH3. For ammonia, the Lewis Structure provides a clear glimpse of where the nitrogen bonds with hydrogen. This model clearly shows that nitrogen still has a lone pair of atoms which causes the atom to have a trigonal pyramid shape.

This triangular shape is also present in the space filling model. The space filling model presents the triangular shape in a more realistic 3D view that clearly shows the close bonds between the hydrogen and nitrogen in the bottom three corners of the ammonia atom.

Again, the unshared electron pair makes a triangular shape in the ball and stick model, however, the degree of the bonds can be more clearly represented being that they are further spread apart compared to the space filling model. Like the Lewis structure, it can clearly be seen that it is a single bond between the nitrogen and its three hydrogen particles.

Finally, in the geometric sketch, the degree of the bond connections is seen in greater detail. Here, the ammonia atom clearly has a very definite triangular shape, with 106 degree bond angle where the hydrogen…… [read more]


Lithium Transition Metal Oxides as Battery Cathode View Paper

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Lithium Transition Metal Oxides as Battery Cathode

"Although the basics of electricity were established in 600 B.C. By the Greek philosopher

Thales of Miletus and then refined by scientist William Gilbert of England in 1600,

the first battery actually dates back to the 18th century"

(Millard, N.d., p.2).

Modern Miniaturization

Contrary to the contemporary trend to supersize fast food portions,… [read more]


Underground Directed by Emir Kusturica or the Periodic Table by Primo Levi View Paper

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¶ … Underground" directed by Emir Kusturica, or "The Periodic Table" by Primo Levi

The Second World War has been the scene of numerous horrible events, but the Holocaust is definitely the most shocking affair from the era. Because of its notoriety, it gave birth to innumerable books, articles, and movies, as people wanted to express their standpoint relating to… [read more]


Reduction Oxidation Redox Signaling in Wound Healing View Paper

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Redox

Reduction-Oxidation (Redox) Reactions and Signaling at Wound Sites: Implications for Healing

Wounds are a natural if not especially pleasant feature of life. All living organisms will experience some sort of unwanted damage to their outer layers potentially due to no more than some wind blown debris, or to their inner workings through the inhalation or uptake of some microscopic… [read more]


Oxidation-Reduction Series of Chemical Reactions View Paper

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Oxidation-reduction-reactions are a series of chemical reactions characterized by electron transfer from one molecular species to another (Kotz, Treichel, & Townsend 141). Specifically, oxidation describes the loss of electrons, while reduction refers to the gain of electrons (Kotz, Treichel, & Townsend 142). The molecular species which removes, or accepts, electrons during an oxidation-reduction-reaction is known as an oxidizing agent, or an electron acceptor (Kotz, Treichel, & Townsend 142). Conversely, molecules which donate electrons are termed reducing agents, or electron donors (Kotz, Treichel, & Townsend 142).

While oxidizing agents frequently contain oxygen, its presence is not a strict requirement for oxidation (Kotz, Treichel, & Townsend 141-143). Oxidizing molecules usually possess a high electronegativity, resulting in a strong attraction toward electrons (Kotz, Treichel, & Townsend 142). In addition to oxygen, the halogens fluorine, chlorine and bromine are common oxidizers that are strongly electronegative (Kotz, Treichel, & Townsend 141-143). In the case of the browning apple, however, the oxidizer is the oxygen present within the air (Nicolas et al.).

Reducing agents are molecular species which reduce other molecules, i.e. they donate electrons to another molecule (Kotz, Treichel, & Townsend 142). Reducing agents tend to be extremely varied and often highly electropositive (Kotz, Treichel, & Townsend 142-143). The high electropositivity accounts for a reducing agents predilection to donate electrons.

The browning of an apple occurs when the skin is broken and cell walls of the apple are compromised (Nicolas et al.). Ruptured cell walls allow the cellular contents to be exposed to the oxygen present within the air. In apples, an enzyme known as polyphenol oxidase facilitates the oxidation process (Nicolas et al.). Polyphenol oxidase, also known as tyrosinase, is an enzymatic protein found within the chloroplast of the apple cell (Nicolas et al.). Polyphenol oxidases function to drive o-hydroxylation of monophenolic compounds to produce o-diphenols and further catalyze the oxidative conversion of o-diphenols to o-quinones (Nicolas et al.). When…… [read more]


Laidler, Keith James. The World of Physical View Paper

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Laidler, Keith James. The World of Physical Chemistry. New York: Oxford University Press,

For many of us, chemistry is a subject in school that 'feels' as if it has always existed because of its apparent certainty regarding the natural world. The World of Physical Chemistry by Keith James Laidler illustrates that this is not the case by highlighting development of chemistry as a discipline. The creation of chemistry as a subject involved a process of discovery that existed in dialogue with history, personalities, and politics.

Chemistry is distinct as a scientific study because it is more concerned with the properties of individual substances, in contrast to physics' concern with general properties of matter (Laidler 5). It is a vast field, spanning the breadth of simple and quantum mechanics, spectroscopy, electrochemistry, colloid and surface chemistry. Laidler begins with how the ancient Greeks like Aristotle understood the atomic nature of matter, Newton and Galileo, as well as the First and Second Laws of Thermodynamics and ends with discussing Brownian motion and the achievements of Niels Bohr.

His book takes us on a tour of the biographies as well as the theories of major…… [read more]


Temperature and Heat View Paper

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Temperature and Heat

Heat affects the temperature of the human body, water, land, atmosphere, and other structures of the earth. This is because the universe is made up of matter and energy. Matter is made up of atoms and group of atoms or molecules. It is energy that causes the atoms and molecules to move. This movement of atoms and… [read more]


History of Atomic Theory View Paper

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History Of Atomic Theory

Atomic theory is one of the most important theories developed in time in the field of physics and chemistry. The theory analyzes the nature of matter, stating that matter is composed of small units called atoms. Atomic theory formed since antiquity and was constantly improved since by the works of scientists.

Initially the theory of matter formed of atoms was approached in a more philosophical way, the scientific part of the theory being developed later in the 19th century. Greek antiques were the first to claim that matter was composed of indivisible units, but their approach was not based on experiment as it was rather a philosophical attempt to explain the universe. The Greek word atomos means indivisible and the theory of atoms was clearly defining that matter was composed of units obtained once you divide matter until no further division is possible, as presented by the Greek philosophers Leucippus and Democritus (History of atomic theory). Some understandings of Aristotle claim that the great philosopher himself allowed the idea that there is a minima in natural things. (Ancient Atomism)

Atomic theory was further analyzed and developed beginning with the 19th century, when John Dalton analyzed more closely the theory of atoms and presented the first results about the nature of atoms. He made a great contribution to the theory as he argued that atoms of one element are identical among each other, but that they are not identical with atoms of a different element. He also argued that combined atoms of different elements can create more complex substances, called chemical compounds (History of atomic theory). Comparing to the Greek theory, Dalton's was focused on the properties of substance and not its form. Dalton's conclusions proved to be correct and although his theory was further developed, he set the basis…… [read more]


Heat Capacity Is Defined by View Paper

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Heat capacity, C of any given system is also noted to be the ratio of the heat that can either be added or effectively withdrawn from the given system in order to give rise to the resultant temperature.

C = ?Q/?T = dQ/dT [J/deg]

This type of definition is however noted to be valid in the absence of any form of phase transitions.

Heat Capacity is noted as the measure of a material's ability to absorb a given amount of thermal energy.

Thermal energy = the kinetic energy of the atomic motions +The potential energy of distortion of the interatomic bonds.

The higher the value of T, the larger the mean atomic velocity and corresponding the amplitude of the atomic vibrations. The outcome is the general rise in the level of thermal energy.

The temperature dependence of the concept of heat capacity

Heat capacity is noted to have a very weak temperature dependence at very high temperatures. This is noted to be true at temperatures that lie above the Debye temperature ?D.It however decreases towards zero as the value of T. approaches zero Kelvin.

The constant value of this quantity ( heat capacity) of several solids is referred to as the Dulong-Petit law. Sometimes in 1819, an experiment performed by Dulong and petite found that for several solids at room temperature, cv ? 25 JK-1mol-1.

This is noted to be consistent with the outcome or theoretical standings of the equipartition theorem of the classical mechanics theories which states that the energy which is added to solids are presented in the form of atomic vibrations with the potential and kinetic energy being associated with each atom's three degrees of freedom.

How the phase of a substance (ie solid, liquid, or gas) changes its heat capacity

Whenever a given material undergoes a change in phase such as from solid to liquid to gas, the heat capacity of such a material is never well defined and the material's heat capacity is technically indicated to be indefinite due to the fact that the heat goes into the given material but the material's temperature remains constant. Due to this fact, the meaning of heat capacity is often restricted to a single phase.

The explanation is that as a solid approaches liquid phase, it begins to soften while the frequency of the modes experience a drop. The heat capacity is therefore noted to increase.The hat capacity of a liquid is however noted to be a bit complex. This is due to the fact that there exists several local clusters of low energy vibration modes which can be excited thermally. The conversion of the substance's frequency modes to the rotational and translational modes is never straightforward.

How temperature is a measure of the kinetic energy of the molecules in a substance

Temperature is noted as a measure of the average kinetic energy of the atoms or molecules of a given substance expressed in terms of degrees that are designated on a standard scale (Mifflin,2000).

References

Cengel, Y.A… [read more]


MRI's Magnetic Resonance Imaging, or View Paper

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However, some people must take some kind of sedation in order to cope with the MRI environment, which in addition to being a very confining space, is quite noisy. The noise is also unsettling to some patients.

A more serious risk is that the patient's body may contain some undisclosed metal object that responds to magnetism (Gould, DATE). The magnetic field of an operating MRI machine is quite intense and can force heavy metal objects out of a person's hands if standing near the machine. For instance, a metal fragment in the eye from an old injury can be moved by the magnetic field and cause serious damage to the person's eye. People with pacemakers must stay far away from MRI equipment, because the equipment can completely disrupt the pacemaker or even cause the person to die (Gould, DATE). Because of this risk, patients must be screened very carefully regarding metal that might be present in their bodies for some reason.

However, there are no known hazards to people from the process of having an MRI performed. In spite of that, erring on the side of caution, MRI's are rarely performed on pregnant women (Gould, DATE) although some recent developments in the use of MRI's may provide important new ways to image high-risk fetuses (Wikipedia, 2005).

Specialized MRI's

Several variants of the MRI have been developed since the invention of the first machine. One is called a Diffusion MRI. The diffusion MRI relies on the fact that water within cells tends to be anisotropic and unlikely to move out of the cell. The diffusion MRI allows the machine to image such things as neurons, because the water in the neuron tends to not cross the myelin membrane covering the neuron. Capitalizing on the predicted action of water molecules within tissue has allowed the development of MRI for use in diagnosis of strokes, Alzheimer's and multiple sclerosis (Wikipedia, 2005).

Other MRI's have been developed that can accurately image arteries, helping with the diagnosis of stenosis, or narrowing of arteries, as well as aneurisms, or balloon-like stretches in artery walls (Wikipedia, 2005).

Another dramatic development has been the ƒMRI, or functional MRI. The functional MRI can make images of the brain as it works by measuring neuron activity (Wikipedia, 2005). It can do this because the parts of the brain that are more active demand more oxygen. The ƒMRI uses magnetic fields to measure increases and decreases of oxygen levels in the hemoglobin of the patient's blood, thus mapping brain activity through time (Wikipedia, 2005).

One of the most recent developments in MRI technology has been that of weight-bearing images. Until this approach was developed, all MRI's were done with the patient lying flat on a table. Now, MRI's can be performed with the patient in a variety of other positions, including standing or bent in various ways (Wendling, 2005). The new positions can reveal problems that were hidden when doing a prone MRI.

MRI's have particular value in helping manage some… [read more]


Surface Plasmon Resonance-Based Biosensors View Paper

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¶ … Plasmon Resonance-Based Sensors

Surface Plasmon Resonance-Based Biosensors

Surface plasmon resonance (SPR) was first observed in 1902 by Wood and this physical phenomenon has since begun to be used in multiple applications. Modern detectors now use the phenomenon to detect sub-monomolecular coverage. Since Wood came across the phenomenon, it has been perfected by Lord Rayleigh, Fano, Krestchmann and Raether. Actual sensors first came into use in 1983 by Liedberg. A good conceptual example is a polarized light being shone through a prism onto a sensor chip assembly with a film of thin metal on top. The shining of the light incites surface plasmons into becoming active and this phenomenon can then be measured. A wave-like oscillation of free electrons is induced and the intensity of the light is reduced in the process. The angle at which the maximum amount of refraction loss occurs is called the resonance angle [1].

Applications

Surface plasmon resonance can be used to determine the concentration of an analyte in a sample during a quantitative analysis session. The analysis involves a calibration curve whereby a response over time to an SPR series is plotted on a graph in the form of a curve. The amount of data points (dilutions) can range from 10 times to 100 or even 1000 iterations. The results of this analysis will depend a lot on the sample size [1].

The most significant benefit of using SPR detection is being able to determine the kinetics of bio-molecular reactions. The interactions of an analyte and a ligand immobilized on the sensor surface can be ascertained using SPR techniques and technology. Assessing and analyzing the process and results of such experiments is not terribly complex or beyond most people's understanding. It is enough to know that an optical method is used to measure the refractive index within proximity of a sensor surface [1].

History

Biosensor as a term…… [read more]


NMR Spectra Nuclear Magnetic Resonance View Paper

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Carbon 13 (13C) is not naturally abundant but provides a spin state of 1/2 or -1/2 and gives a NMR signal. NMR spectroscopy of 13C observes the skeleton of an organic molecule and allows determination of the chemical shift for every carbon atom whether a proton is attached or not. One useful property of 13C NMR is the broad chemical… [read more]


Entropy Indeed, Entropy Governs Life. View Paper

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In understanding this one must recognize the concept of activation energy. (Clymer, 2002) This is a barrier to spontaneous conversion of reactants to products. Temperature, concentration and the use of catalysts often lower the activation energy. For example, a mixture of hydrogen and oxygen, even in 2:1 molar proportions will not form water spontaneously. The activation barrier has to be overcome by means of a spark, which causes an explosive reaction, thus forming water. A barrier to spontaneous energy dispersal does not mean that the law of entropy is defeated. Both laws of nature are sacrosanct.

To prove this, one might consider the phenomenon of photosynthesis. The leaf captures a very minute percentage of the sun's energy. This energy is dispersed throughout the leaf where food is prepared using carbon dioxide releasing water and oxygen. Some of the energy is also used to build food molecules (chloroplasts). This reconstituting of energy is against the law of spontaneous dispersal. This does not however, defeat the entropy laws. Photosynthesis is a naturally occurring process. Which means the overall entropy change should be positive. In photosynthesis, the overall energy dispersed is more than twice that which is used in recreating food molecules.

Another similar example can be seen in the workings of the mammalian body. The energy supplied from the outside in the form of food combined with the air we breathe is then converted into energy. This concentrated form of energy is dispersed throughout the body, the circulatory system and governed by the central nervous system. This energy dispersal and the processes of metabolism allow our bodies to remain at a constant temperature. Entropy is therefore governed by an energy gradient and dispersed from a high-energy point to a low energy point. This is necessary as is the spontaneity. Consider if the flow of energy was reversed and energy flowed from a lower to higher gradient with negative entropy changes. The move towards equilibrium would be defeated and life would cease to exist.

In identifying entropy changes along an energy gradient, one must identify a gap in the description of the Second Law. Namely, that this law does not indicate the path that energy dispersal takes, assuming that there are more than one available path. This gives rise to the notion of maximum entropy. (EntropyLaw, 2004) And it indicates that the path of maximum entropy is associated with the path of minimum gradient. To explain this, consider an airtight box at a higher temperature than the surroundings. Here the energy dispersal takes place through conduction across the walls of the box. If a door were cut into the box, maximal energy dispersal would take place along the path through the door or the path with the minimum energy gradient.

Entropy is very important. It governs every physical, chemical and biological aspect of life.

Bibliography

Atkins, P.W., and Julio De Paula. Physical Chemistry. 7th ed. New York: W.H. Freeman, 2002.

Clymer, Jeffrey. Arrhenius Calculation. 2002. Nuvox.net. Available:

http://members.nuvox.net/~on.jwclymer/arr.html. July 1, 2004.

EntropyLaw. The… [read more]


Chemistry Problems Acids and Bases View Paper

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Chemistry Problems

Copper (II) hydroxide (used as a pigment) is insoluble in water

BaBr2 (used to make photographic compounds) is soluble in water

Silver carbonate (used as a laboratory reagent) is soluble in water

Pb3(PO4)2 (used as a stabilizing agent in plastics) is insoluble in water

Upon colliding with a water molecule (H2O), the hydrofluoric acid molecule (HF), an H+ is available to transfer to the water molecule. This creates a hydronium ion (H3O+) along with a flouride ion (F-), which is often formed in reverse when it reacts with hydronium ions that attach and pull H+ ions as it tries to reform HF and H2O. Both sets of reactions, regular and reverse, occur simultaneously and continuously within the solution until they reach an equal rate, where there are no additional changes to the numbers of HF, H2O, F-, or H3O+.

a. Oxyacid

b. Polyatomic ionic compound

c. Polyatomic Ionic compound

d. Binary Ionic compound

e. Binary acid

f. binary Ionic compound

g. Binary Covalent compound

59. a. Strong Acid

b. Weak Base

c. Strong Base

d. Weak…… [read more]


Electrolytic and Voltaic Cells View Paper

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Electrolytic and Voltaic Cells

An electrolytic cell is a cell that is made up of two electrodes touching an electrolyte and that causes a chemical reaction when connected to an external source of electricity. The electric energy is used to decompose chemical compounds and the process is referred to as electrolysis, this leads to an increase in the chemical energy. This cell has three major components, the electrolyte, an anode, and a cathode. The anode and cathode are usually referred to as electrodes. The electrolyte is normally water solution or any other solvent that ions can dissolve in example being salts like sodium chloride. The application of external voltage to the electrodes makes the electrolyte to produce ions which flow to and from the electrodes where redox reaction takes place. The applied electrical energy reverses the effect of impulsive chemical reactions.

A voltaic cell is a device that converts chemical energy into electric energy this it does by deriving electrical energy from the chemical reactions that take place within, it is also referred to as an electrochemical cell. This device is made up of two distinct metals linked by a salt bridge or single half-cells separated using a porous film. Every half-cell consists of a metal and a salt solution corresponding to the metal. In the salt solution is contained the metal's cation and an anion to bring balance on the cation's charge. Basically the half-cell has the metal in two oxidation states and the type of reaction that takes place within it is redox reaction. In this cell, one metal is capable of reducing the cation of the other; on the other hand, the first metal can be oxidized by the cation. There is need to avoid the mixing of the two half-cells thus they must be physically separated. The quantity of electrons transferred in either direction must be equal thus combining the two half-cells gives the whole-cell electrochemical reaction. Therefore, to get the voltage of the cell, the voltages of the two half-cells are added.

Therefore, the contrast that…… [read more]


Heat and Temperature View Paper

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Heat and Temperature

The Kinetic Theory of Matters is mainly focused on the facts that everything is composed out of moving particles and this movement is accelerated if temperature is increased. Heat is transferred through atoms or molecules moving and thus transmitting energy. A body's temperature can be found by measuring the average kinetic energy of the particles that it contains.

Heat can be transferred through three processes: conduction, convection, and radiation. Conduction is the process during which heat is transferred through a solid body that is heated. During the process of convection, particles that are heated transmit heat to another body. Radiation is different from conduction and convection because it can transmit heat through open space, given that it does not require contact between two matters in order to do so.

The Universe is composed out of two elements: matter and energy. Considering that matter is composed out of atoms and molecules, these two are influenced in constantly moving because of energy. Energy causes atoms and molecules to collide with each-other or to simply move back and forth, vibrating. By moving, atoms and molecules generate a type of energy referred to as either heat or thermal energy. Heat is present in all matter, regardless of the temperature matter has. Energy can easily change form and it can be converted into a series of forms. Heat energy can result from a multitude of energy forms, ranging from mechanical energy until nuclear energy. Heat energy occurs when a body transfers its warmth to another body, when each of the bodies had a different temperature.

In order to determine temperature, one must examine the average heat of the molecules and atoms contained by a body. Atoms and molecules are not always travelling at the same speed, thus meaning that some can move slower and others can move faster. The number of atoms and molecules in a substance cannot influence the respective substance's temperature, since the measurement is average. Even when a particular object has a large number of particles in addition to another, the temperature of the two bodies can be the same.

Temperature is something people feel on a daily basis, considering that weather can largely influence the temperature in our bodies. Individuals most often relate to temperature when they consider the terms hot and cold. Temperature is determined by thermometers that can be graded in a variety of ways, with some of the most often scales used at determining temperature being Celsius (used by most of the world), Fahrenheit (used rarer, by…… [read more]


Genetics and Evolution View Paper

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Biology

Genetics and Evolution

UCLA chemists report having created a synthetic "gene" that could capture heat-trapping carbon dioxide emissions, which contribute to global warming, rising sea levels and the increased acidity of oceans. They have taken both organic and inorganic units and joined them into a synthetic crystal which codes information like DNA does. It is in no way as sophisticated as DNA, but it is new to the fields of chemistry and materials science (Chemists Create Synthetic 'Gene-Like' Crystals for Carbon Dioxide Capture, 2010).

In the early 1990s, classes of materials called metal-organic frameworks (MOF's) were invented. These are sometimes described as crystal sponges because the workings can nearly be changed at will. MOF's have pores or openings in which gases can be stored that are usually difficult to store and transport. Molecules can go in and out of the pores unhindered. UCLA chemists have created crystals of metal-organic frameworks in which the sequence of multiple functionalities of varying kinds and ratios act as a synthetic gene. With…… [read more]


Nitrogen Cycle View Paper

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¶ … Nitrogen Cycle

As an essential element in the formation of amino acids and thus proteins -- the basic constituents of all organic matter -- nitrogen is a necessary nutrient to absolutely all life forms on Earth (Killpack & Bulchholz 2010). This is no less true of human beings than it is of other organisms; almost every system in the human body has at least an indirect reliance on proper nitrogen levels being maintained. All life is built of proteins, but nitrogen is even more important in terms of metabolism, growth, and reproduction (Pidwirny 2006). In addition to being one of the basic elemental constituents of amino acids and proteins, nitrogen is also necessary in nucleic acids -- like DNA -- meaning that cellular reproduction and repair cannot occur without adequate nitrogen supplies. It is for this reason that every system in human beings -- and indeed in all animals -- is dependent on nitrogen.

It would seem, then, that nitrogen must be readily available to all of these organisms, but this is not actually the case. Though nitrogen is the most abundant element in the Earth's atmosphere, nitrogen gas -- N2 -- cannot be utilized by most life forms. This is where the nitrogen cycle comes into play. Through a complex series of chemical changes wrought by various organisms and certain other processes, the nitrogen gas in the atmosphere is converted into more usable forms and, after being used as a nutrient by organisms throughout the web of life is eventually returned to the environment and the atmosphere (Elmhurst 2009). There are many different chemical changes that occur at each step in the nitrogen cycle, each of which has major important effects on both the ability for organisms to utilize nitrogen and on the environment as a whole.

It is possible for nitrogen in the atmosphere to…… [read more]


Nitrogen Cycle View Paper

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¶ … Nitrogen Cycle

As the most abundant element in the Earth's atmosphere, nitrogen might be thought to be an easily accessible nutrient for the planet's many life forms. In fact, however, nitrogen's abundance has very little to do with its availability as a nutrient in any sort of direct way. Before the nitrogen gas -- N2 -- in the atmosphere can be utilized by plants -- and before those plants can be eaten by organisms higher on the food chain like human beings -- it has to be converted into different forms (Kimball 2008). Namely, it has to be taken out of its gaseous state and converted to other forms in other molecules in order to be absorbed and used by plants (Harrison 2003). The process by which this occurs is one of the most remarkable and one of the most necessary cycles to have come into existence, and is both fairly simple and, on a deeper and more practical level, stil not fully understood.

The first step in the nitrogen cycle is nitrogen fixation. In this process, bacteria and some other microorganisms in the Earth's soil convert atmospheric nitrogen gas into ammonia, managing to split each double-atom molecule of nitrogen gas and pairing each individual atom with three hydrogen atoms (Harrison 2003). The manner in which bacteria manage this feat -- both the splitting of the nitrogen gas molecule and the fusion of the ammonia molecule -- is not fully understood by science; industrialization has allowed for the human creation of ammonia from the raw elements, but it requires great heat and pressure -- far more energy than the bacteria and microorganisms exert doing the same job (Kimball 2008). Regardless, this process does take place, and the ammonia is either used directly by plants or is further converted by bacteria before being taken up by other organisms.

At this point, the nitrogen has become fixed and is now…… [read more]


Teaching a Textbook Passage Most of the View Paper

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Teaching a Textbook Passage

Most of the Universe consists of matter and energy. Energy is the capacity to do work. Matter has mass and occupies space. All matter is composed of basic elements that cannot be broken down to substances with different chemical or physical properties. Elements are substances consisting of one type of atom, for example Carbon atoms make up diamond, and also graphite. Pure (24K) gold is composed of only one type of atom, gold atoms. Atoms are the smallest particle into which an element can be divided. The ancient Greek philosophers developed the concept of the atom, although they considered it the fundamental particle that could not be broken down. Since the work of Enrico Fermi and his colleagues, we now know that the atom is divisible, often releasing tremendous energies as in nuclear explosions or (in a controlled fashion in) thermonuclear power plants."

On-Line Biology Book

http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookTOC.html

Before opening the textbook to this rather dense passage, I would begin a discussion to ascertain what the students knew and understood of their world, and specifically the topics discussed here. I expect many students would have heard of atoms, and might have a basic understanding of what atoms are. Tapping into their ideas will allow this passage to be tied into what they already know, aiding their understanding of these complex though relatively basic…… [read more]


Origin of Life View Paper

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¶ … Origin of Life

There are currently many different competing theories on how life originated on this planet. One of these theories involves the early state of the atmosphere. According to this theory, the first step in the origins of life was the spontaneous formation of carbon compounds in Earth's then carbon-rich atmosphere. There is substantial evidence that these compounds could have formed -- they are a common occurrence throughout space, and experiments have shown that even amino acids, the building blocks of proteins, can be formed under conditions similar to those that existed at a certain point in the Earth's past. The theory goes that after these amino acids and other organic compounds formed, they eventually came together to form more complex systems, at some point coalescing into unicellular organisms. There is no way to prove, however, that this is actually what happened, and as yet no mechanism described for how the various simple organic compounds could have organized themselves into more complex cells that exhibited signs of life. The process would have taken millennia at the least, and time is one of the few things that cannot be…… [read more]


Silica Use View Paper

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Silica Use

Silica usage and safety

Silica is the second most commonly found mineral on earth and comprises almost thirty percent of the Earth's crust by weight. (Silica Dust Exposure) Silcia, or silicon dioxide (SiO2) also known as alpha silica or free silica, is described as a crystal which is "... tiny, very hard, translucent, and colorless" (Silica Dust Exposure).… [read more]


Beginnings of Life on Early Earth View Paper

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¶ … Life on Early Earth

Questions related to the origins of life on Earth have always been a cause for scientific investigation and suppositions. If we refer to the naturalistic approach, than the evolutionary process is a justified explanation of changes and transformations that have occurred. This is a theory that we can successfully apply to the appearance of… [read more]


Radioactivity the Transformation of Atoms View Paper

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Contrary to this the gamma radioactivity is associated with transmutation of the nucleus. It is the consequence of emission by the nucleus, of an electromagnetic radiation such as visible light or X-rays, however, are considered more energetic. (What is radioactivity?)

The energy generated by the process of radioactivity has significant military and industrial utilities. But the rays emitted out of radioactive substances results in radiations sickness and such substances are required to be dealt with much care. The nuclei of elements in the process of radioactivity tend to be highly unstable and are taken to be undergoing persistent disintegration known to be radioactive decay. (Radioactivity: The Columbia Encyclopedia) Radioactive decay is considered to be a group of various processes by which emission of subatomic particles is evident by the unstable atomic nuclei. Radioactive decay is applied in the tools of radio isotopic labeling which is considered useful in tracking the path of a chemical substance through a complex system like inside the living organism. (Radioactive decay: Wikipedia, the free encyclopedia)

References

Radioactive decay. Wikipedia, the free encyclopedia. Retrieved from http://en.wikipedia.org/wiki/Radioactivity Accessed on 17 February, 2005

Radioactivity in nature. Idaho State University. Retrieved from http://www.physics.isu.edu/radinf/natural.htm

Accessed on 17 February, 2005

Radioactivity. The Columbia Encyclopedia. 2001. Retrieved from http://www.bartleby.com/65/ra/radioact.html Accessed on 17 February, 2005

What is radioactivity? Retrieved from http://www.ccr.jussieu.fr/radioactivite/english/what_is_radioactivity.htm Accessed on 17 February, 2005… [read more]


Radiometric Dating in 1896, French View Paper

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The rate of decay is expressed in terms of an isotope's half-life, or rather the time for one-half of a particular radioactive isotope in a sample to decay (Time pp). Although most radioactive isotopes lose their radioactivity within a few days or years, some, however, are slow to age, and several of these are used as geologic clocks (Time pp). Dating rocks by these radioactive clocks is rather simple in theory, however, the laboratory procedures are complex (Time pp). The numbers of parent and daughter isotopes within each specimen are determined by a variety of analytical methods, and the difficulty lies in the precision of measuring very small amounts of isotopes (Time pp).

All carbon in living organisms has a constant proportion of radiocarbon to non-radioactive carbon, and after the organism's death, the amount of radiocarbon gradually decreases as it reverts to nitrogen-14 by radioactive decay, and by measuring the amount remaining, the amount of carbon-14 in the materials can be calculated and the time of death can be determined (Time pp).

This radiocarbon timepiece has become a very useful and efficient tool in dating important episodes in the recent prehistory and history of man, however, due to the relatively short half-life of carbon-14, this method of calculation is limited to dating events that have taken place only within the past 50,000 years (Time pp).

Works Cited

Radiometric Dating

http://www.gpc.edu/~pgore/geology/geo102/radio.htm

Radiometric Time Scale

http://pubs.usgs.gov/gip/geotime/radiometric.html… [read more]


Due to His Work on View Paper

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For example:

If there was a gas that exerted 10 atm of pressure and took up a space of 3 liters, and it was decided to expand the space to 7 liters, what would be the new pressure, assuming that temperature remains constant?

The equation PV = k will tell what the constant for this gas is. However, since the… [read more]


Collision Model: Explanation and Application View Paper

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At the time of collision, bonds are stretched and broken as new bonds are made. Breaking these bonds and rearranging the atoms during the collision requires the input of energy" (Hutchinson 2006).

Different experimental parameters will thus impact the product of the Arrhenius Equation. For example, the Arrhenius Equation can show the effect of a change of temperature on the "rate constant" and therefore the change in the rate of the reaction (Clark 2002). If the rate constant doubles, the rate of the reaction will likewise double. Also, the equation shows how "a catalyst will provide a route for the reaction with lower activation energy" (Clark 2002). A catalyst is a substance that speeds up a reaction without changing its own substance, lowering the activation energy required for reactions and allowing collisions to be more effective, and more collisions and more reactions. A homogeneous catalyst is present in the same phase as the reacting molecules while a heterogeneous catalyst exists in a different phase then the reacting molecules, such as a solid ("Chemical Kinetics: Chapter 12," AP Chemistry Notes, 2008).

Despite its original design to be applied to gaseous substances alone, the Arrhenius Equation's explanation of collision models have been used in a variety of disciplines. For example, in a biology experiment involving collagen shrinkage in which rat tails were used as the test medium, given a "widely investigated property of collagen is its hydrothermal shrinkage," the Arrhenius Equation was used to examine if collagen shrank under different temperatures in a way that substantiated the theory of the "hydrothermal stability of collagen" (Akeson 1963). "Shrinkage curves constructed from data on length of fibers plotted against time at various temperatures clearly establish[ed] that the process of shrinkage of collagen" was "a rate phenomenon and that a true shrinkage temperature does not exist from a thermodynamic point-of-view" (Akeson 1963).

This shows that although originally developed to study gasses, the Arrhenius Equation has a variety of applications in experiments involving rates of reaction and molecular collision. It quantifies what many people have observed anecdotally, namely that the hotter the flame, the more quickly water converts to gas, and salted water comes to a boil more quickly than unsalted water. It also allows for how the presence of catalysts can affect reaction rates. The collision of molecules, and the degree to which molecules will collide all affect reaction rate, and the Arrhenius Equation makes these observations useful to scientists in a predictable way.

Works Cited

Akeson, Wayne H. "Application of the Arrhenius Equation to rat tail tendon collagen."

Nature. 199, 185-186. 13 July 1963. 1 Oct 2008. http://www.nature.com/nature/journal/v199/n4889/abs/199185a0.html

The Arrhenius Equation." IUPAC Compendium of Chemical Terminology. 2nd Edition. 1997.

Oct 2008. http://www.iupac.org/goldbook/A00446.pdf

The Arrhenius Equation." Shordor Education Foundation. Department of Chemistry.

University of North Carolina, Chapel Hill. Sept. 30, 2008. 1 Oct 2008. http://www.shodor.net/unchem/advanced/kin/arrhenius.htm

Clark, Jim. "Rate constants." 2008. 1 Oct 2008. http://www.chemguide.co.uk/physical/basicrates/arrhenius.html

Chemical Kinetics: Chapter 12." AP Chemistry Notes. 1 Oct 2008. www.mpsomaha.org/mnhs/apchem/assignments/Notes/Html%20Notes/notes12.htm

Collision Model." Science Glossary. Answers Corporation, 2006. Answers.com 30 Sep.… [read more]


Corrosion in Reinforced Concrete Structures View Paper

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Corrosion in Reinforced Concrete Structures

The report demonstrates the corrosion process in reinforced concrete structures. Corrosion is a gradual destruction of concrete, metal and steel structure generally caused by the chemical reactions. The chemical process of corrosion involves the combination of anode, cathode and electrolyte, and the presence of water and oxygen are the major agents of corrosion. Typically, rusting… [read more]


Properties of a Carbon Atom View Paper

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-Describe the basic characteristics of cancer cells?

Cancer cells can be deadly and harmful to all the living things they come into contact with. Cancer cells lose the ability to communicate with other cells through chemical signals. They also lose sensitivity to anti-growth signals from surrounding cells. These signals normally restrict cellular growth. Cancer cells do not have a fixed lifespan. As long as they are able get the nutrients needed to survive, cancer cells are essentially immortal. They will continue to live and divide at an uncontrolled pace unless something happens to stop them. Malignant cells that cause cancer all have the ability to evade the body's cancer surveillance system as well.

-Evaluate why meiosis and sexual reproduction are important in responding to the changing environment?

In meiosis, variation occurs, because each gamete (either sperm or egg) contains a mixture of genes from two different parent chromosomes in sexual reproduction. In other words, the genetic coupling of non-identical DNA takes place in meiosis. It results in an offspring, which has the genetic material of two different individuals. A new combination of genetic information is produced in the gametes. Therefore, in meiosis, the characteristics of parent chromosomes are combined with the characteristics of offspring chromosomes, which ultimately results in a new and unique set of chromosomes. These chromosomes contain the basic DNA chain, which determines the physical and genetic characteristics of the child.

-List the three domains of life and summarize two characteristics that define each of the three domains.

The three domains of life are the Archaea Domain, the Bacteria Domain and the Eukarya Domain. The Archae Domain consist of prokaryotic cells which are membranes. They can withstand high temperatures. Bacteria are prokaryotic cells too but they are made of fatty acid chains. This domain is very diverse and their trillions of species. The Eukarya Domain are eukaryotic cells. Animals, plants and fungi are all part of this domain.

-Discriminate between ancestral and derived traits?

A derived trait is a trait that the current organism has, but the previous one did not have.

An ancestral trait is a trait that you, and…… [read more]


Chadwick Learned to Love the View Paper

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It only took Chadwick one month to discover the conclusive evidence that the neutron did indeed exist; the journal Nature published the report in 1932.

B. Chadwick described a neutron as " a highly penetrating neutral particle with a mass similar to the proton," ("The Neutron: Chadwick 1932," n.d.)

C. Chadwick explained the phenomenon in terms of snooker balls, noting that when the alpha particles from a radioactive source hit a nuclei, a proton is knocked free leaving behind a particle -- suggesting that the neutron is the same mass -- just as when a snooker ball is hit by a ball of the same mass it remains stationary.

IV. The Aftermath

A. Chadwick earned the Nobel Prize for his work.

B. Unfortunately, the work from Chadwick's discovery would be harnessed for great evil, causing Chadwick considerable consternation

1. He disparaged the way science was headed toward harnessing discoveries like his for military purposes.

2. He especially feared the American control of science (Oliphant, 1982).

C. Chadwick's discovery led to a "revolution in warfare," a "new source of energy," and "fundamental changes" to the study of science (Oliphant, 1982).

Reference

"1932 Discovery of Neutrons by James Chadwick." Retrieved online: http://library.thinkquest.org/27954/neutron.html

Breithaupt, J. (2000). New Understanding Physics for Advanced Level Fourth Edition. Nelson Thornes.

Colwell, C.H. (2012). Famous experiments: the discovery of the neutron. Retrieved online: http://dev.physicslab.org/Document.aspx?doctype=3&filename=AtomicNuclear_ChadwickNeutron.xml

Nave, R. (n.d.). Discovery of the neutron. Retrieved online: http://hyperphysics.phy-astr.gsu.edu/hbase/particles/neutrondis.html

Oliphant, M. (1982). The beginning: Chadwick and the neutron. In Bulletin of the Atomic Scientists.

"The Neutron: Chadwick, 1932," (n.d.). Retrieved online: http://www-outreach.phy.cam.ac.uk/camphy/neutron/neutron5_1.htm… [read more]


Stars Are One of the View Paper

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[MARK S. GORDON]

Conclusion

Hydrogen and helium constitute the Major share of the elements in the stars. (and the universe). There is a continuous fusion reaction in the stars and their life depends on the amount of fuel left. The presence of higher elements and metals are a direct result of fusion of these basic elements. Spectroscopy has been one of the oldest and trusted methods of studying the elemental analysis of stars and other luminous heavenly objects. The results that we have achieved with spectroscopy have been amazing and we have successfully identified the core elemental composition of different stellar classes. Using spectroscopic observations we have successfully established the radial velocities and the elemental abundances of even the extra galactic objects. For example we have found that many of the extra galactic objects are moving away from us by their red shifts. The availability of specific spectroscopy software has further fastened our study of the molecular mechanics and quantum mechanics. Despite the new advancements in gamma ray and x-ray astronomy optical spectroscopy still continues to be an important tool in our study of vital information pertaining to the nature and the composition of our universe.

Bibliography

MARK S. GORDON, MICHAEL W. SCHMIDT, "RECENT ADVANCES IN QM AND QM/MM METHODS," Accessed on December 19th, 2003, http://www.msg.ameslab.gov/Advances/gamess_paper.march16.html

C.R Kitchin, "Optical Astronomical Spectroscopy," IOP publishing Ltd., 1995

I.S Glass, "Handbook of Infrared Astronomy," Cambridge University Press, 1999… [read more]


Polymer Analysis (Kevlar) Brief History View Paper

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6). The two compounds, Kevlar and Nomex, are distinguished by the structure of their polymer chains, with Kevlar containing para-oriented phenyl rings and Nomex containing meta-oriented rings as shown in Figure 1 below:

Figure 1. Nomex and Kevlar Polymer Chains [Source: Stevens & Kauffman, 2004].

Nomex and the comparable aramids being marketed by other companies today are generally dry-spun from… [read more]


Of Nebulas, Massive Clouds Comprised View Paper

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Large stars can burn out faster than small stars because they burn energy at a higher rate. This is why many small stars will have a longer life span than a larger star: they do not consume their fuel as fast and thus remain alive longer. When the star stars to burn up its helium reserves, the star is on its last years of its life. This is because it requires more energy to fuse helium than it does hydrogen, thus expending the star's energy rapidly. When the star starts burning helium, its temperature and intensity can be stronger than ever before during its life cycle. This stage of the star's life is referred to as the red giant stage. Red giants are bright but are becoming less stable than they were before. Their volatility is due to their burning of carbon. The death of stars is difficult to document and measure.

A Hertzsprung-Russel (HR) Diagram represents stars visually as dots, plotted on a graph using two axes: absolute magnitude (which is basically luminosity, measured in energy emissions per second), and surface temperature measured in Kelvin. What the HR Diagram is especially good for is showing the relational values of the stars' luminosity and temperature. The reference point for the HR diagram is the sun, which provides a means by which to visualize the magnitude or temperature of other stars in relation to it. Basically, stars are ranked according to relative hotness and brightness. Most stars fall within a median range called main sequence, which is akin to the average of stars. Tjhis is because most stars follow a predictable pattern in that large stars can burn bright and hot. Some, but not all, HR Diagrams, also include factors like the color of a star, measured with spectrophotometers.

Reference

"Star Life Cycle." Retrieved online: http://sunshine.chpc.utah.edu/Labs/StarLife/starlife_main.html… [read more]


How Aspirin Is Prepared in the Lab View Paper

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2 grams of the salicylic acid is scooped into the tray and the mass of salicylic acid is recorded. The salicylic acid is then transferred to a 125-ml Erlenmeyer flask. Place 4 ml of acetic anhydride into the Erlenmeyer flask, mix and record the volume of acetic anhydride added. Add 5 drops of concentrated sulfuric acid / The salicylic acid should completely dissolve and result in a clear mixture. Go on swirling it. Place 1-2 ml chilled RO/DI water to the flask from a 10-ml graduated cylinder to decompose unreacted acetic anhydride. Mix and swirl with every addition of water. Set up you're your vacuum filtration apparatus. Add now 25 ml chilled RO/DI water to the reaction mix in the flask. Break lumps with a glass stirring rod. Weigh and record the mass of the filter paper. On the Buchner funner, moisten it with 1-2 ml of the RO/DI water. Turn on the aspirator so the moisture in the tunnel would go into the filter paper and seal it to the funnel. Swirling the mixture, pour it into the funnel at the center of the filter paper. With the aspirator on, rinse the aspirin with 15 ml of the chilled RO/DI water and keep it on for 10 minutes to drain the aspirin as much as possible. Then remove the clamp from the tubing to release. Transfer the filter paper and crystals into a weighed watch glass and store until completely dry.

4. Conclusion

This experiment shows that aspirin can be prepared from a mix of salicylic acid and acetic anhydride with salicylic acid as the limiting reactant. As plain salicylic acid, it irritates the stomach. But when hydrolyzed, it is less irritating and beneficial.

BIBLIOGRAPHY

CSUS. Synthesis of aspirin. Department of Chemistry: California State University, 2014.

Retrieved on October 28, 2014 from http://www.chem.csustan.edu/consumer/aspirincons/aspirincons.htm

Smith, K. .S. Preparation of Acetylsalicylic acid. Department of Chemistry: Michigan

Technological University, n.d. Retrieved on October 28, 2014 from http://www.chemistry.mtu.edu/kmsmith/syp/Student/Tuesday/Aspirin.pdf… [read more]


Admissions Essay Plus a Letter of Recommendation View Paper

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¶ … mom and I huddled in the corner when the police came. They banged on the door, shouting for my father. How did I get here? Why was my family running from the law? My dad had simply joined the Chinese Democratic Party in the United States, but this was a forbidden membership in China. The Chinese Democratic Party… [read more]


How the Process of a Battery Works View Paper

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¶ … Battery Works battery (also called electric cell) is a device that converts chemical energy into electricity. It consists of a container full of chemicals that produce electrons as a result of chemical reaction. It also has two terminals, one positive (+) and the other negative (-).When the two terminals of a battery are connected through a wire or a device such as a light bulb or a motor is connected across the terminals, the chemical reaction inside the battery starts and electrons flow from the negative terminal to the positive terminal, providing the required electric current to run the device. (Brain, 2007)

We can visualize the process taking place inside a battery by examining what an electric current is. Each atom consists of a tiny, positively charged nucleus surrounded by a number of even smaller, negatively charged particles called electrons. The charge on the nucleus is equal in size to the total charge of all the electrons in an atom, which makes atoms electrically neutral. However, atoms can lose or gain electrons to become positively or negatively charged; in such a state they are called ions ("How do..." n.d.) the top wire in the figure below shows an electrically neutral wire in which the positively charged ions (red) and the negative charges (blue) are balanced. However, if the negatively charged electrons get concentrated at one end of the wire, they would rush towards the positively charged ions at the other end of the wire to balance out the positive charges. Such a flow of negatively charged electrons appears as an electric current in the wire as shown in the wire at bottom below:

Such an imbalance of the negatively and positively charged ions make electric current flow between the negative and positive terminals of the battery.

Chemical Reaction Inside a Battery: Although there are different types of batteries such as zinc-carbon battery (the commonly used, inexpensive dry battery cells), lead acid battery (used in automobiles) or the Nickel-metal hydride battery (rechargeable, dry batteries),…… [read more]


Biochemistry the Polypeptide Chain Configuration View Paper

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"

The authors also quote heavily from previous studies both in order to bolster their own as well as to indicate the variances in the molecules studied. For instance, they point to Perutz to indicate the dimensions of a hemoglobin molecule and how these an relate to helical configurations in a keratin molecule. This is important, because hemoglobin could thus predict that molecules with such a specific helical configuration, according to the authors, "would be spaced about 11 A apart (from center to center), in agreement with Perutz's conclusion that the rods in hemoglobin are about 10.5 A apart. (A calculation of this sort at once eliminates the 5.1-residue helix, for which the predicted average spacing of the rods is 14 A.)" The authors thus find, after further evaluation, that because of such structures, such things as side-chain atoms are as a result of the findings, more randomly arranged than previously believed.

For this reason, the authors also conclude that by comparing radial distribution functions they have given additional evidence in favor of the suggestion by Perutz that rods in hemoglobin molecules have 3.7 residue helical configurations. The author also discuss that it is quite likely that such a configuration is present in…… [read more]


Chemical Reactions Occur When Atoms, View Paper

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This reaction pair is important because the phosphate group is strongly electronegative and bonds formed with the phosphate group have the potential to be high energy bonds. Dephosphorylation is the reverse of phosphorylation, removing one of the phosphate groups.

An isomerization reaction occurs when the atoms of a molecule are rearranged, but there is no addition or removal of atoms. For example, glucose and fructose are isomers of each other; both molecules have the same molecular formula, but differ in the arrangement of the atoms.

Oxidation and reduction reactions involve the addition or removal of oxygen or hydrogens. These are among the more complex, but also most important reactions in living systems. Oxidation reactions involve either the addition of oxygen or the removal of hydrogen, hydrogen ions, or electrons. Reduction reactions involve the removal of oxygen or the addition of hydrogens, hydrogen ions, or electrons. Often oxidation and reduction go hand in hand, as hydrogen is removed from one molecule and added to another. When both halves of the reaction are considered together, they may be referred to as redox reactions. Oxidation reactions are exergonic and reduction reactions are endergonic. These reactions are particularly important during the metabolic pathways of cellular respiration, where chains of oxidation-reduction reactions cause electrons to be passed from one carrier molecule to another along the electron transport system.

Overall, chemical reactions are caused by the destruction of existing chemical bonds and formation of new bonds. These reactions are necessary for many physiological functions and thus, have great practical significance in humans.… [read more]


Physical Phenomenon View Paper

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Lightning - Dramatic Electrostatics

When people are asked to name a force of nature, far more will refer to the force of gravity than to the electrostatic force. True, the force of gravity works over much larger distances than does the electrostatic force, but the fact that matter exists at all is directly due to the electrostatic force itself. Without it, electrons would not orbit the nucleus of an atom and chemical compounds would be impossible. Water exists solely due to the electrostatic attraction between hydrogen and oxygen atoms, similarly for every other chemical compound in the universe. Without the electrostatic force, the universe would exist (if at all) as only an undifferentiated swarm of subatomic particles whose interactions would be entirely random.

Nevertheless, all it takes is a stumble on rocky ground to convince one of the power of gravity, whereas electrostatic phenomena are usually far less dramatic - a shock gotten from touching a doorknob in winter, for instance.

Electrostatic phenomena have been the subject of human curiosity and comment for ages. The ever-observant ancient Greeks knew that under certain circumstances, pieces of amber could influence small pieces of fabric or dust. But it was Franklin's 18th century efforts to understand electricity that should be considered the birth of real scientific inquiry into the field of electrostatics, because it was Franklin who first seems to have identified the positive/negative nature of electricity and who invented the lightning rod, after rightly understanding what it was about rooftops and church steeples that lightning seemed to favor (Jefimenko, 1973).

Although lightning can even strike on a sunny day (Wikipedia, 2005), most terrestrial lightning is generated through two interactive processes: triboelectricity and electrostatic induction.

The triboelectric effect is the tendency of objects of dissimilar materials to accumulate electric charges when put in contact with each other and depends on the relative tendency of these materials to either accumulate or give up electrons (though even identical materials will tend to develop small differences in charge if rubbed together). Materials' relative tendency to do this has been plotted on what is called the Triboelectric Series (Noon, 1992). Polyvinyl chloride (PVC) tends to accumulate electrons and so is toward one end of the series, while glass tends to give up electrons and is positioned toward the other end. If glass and PVC are brought into contact with each other, the PVC will become negatively charged and the glass positively charged. This is the basis of many electrostatic generators, such as the Van de Graaff generator.

In a thunder cloud, the two dissimilar materials are ice and liquid water. Most thunderclouds' bottoms are at about 5km above Earth's surface, where it is usually sufficiently cold to freeze any liquid water. Powerful winds circulate up and down the interior of a thunderstorm, bearing up small drops of freezing water which collide with descending hail stones. Even though these two objects are made from water, the fact that one is large and solidly frozen while one is small… [read more]


Heat Loss View Paper

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Mechanisms of Heat Loss

Heat Loss

How the Rate of Heat Loss is affected by Surrounding Temperatures

Heat transfer occurs whenever there is a temperature differential between a substance and its environment. This differential can be highly significant, or it can be mild and nearly undetectable. The issue is not the strength of the differential, but whether it exists at all. If the substance is at a higher temperature than its surroundings it will lose heat, and if at a lower temperature, it will gain heat. The significance of the differential will affect how quickly the substance gains or loses heat, and can also affect how much heat is lost overall - whether that heat is lost rapidly or whether it dissipates more slowly over time. When heat transfer does occur, it is through one of three separate mechanisms: conduction, convection, and radiation. In order to have a clear understanding of these mechanisms and their relationship to heat transfer, it is necessary to address each one individually. That will allow for a better understanding of how each mechanism works, how they differ from one another, and the ways in which they are similar.

Conduction is a process of diffusion, with the transfer of kinetic energy, in the form of heat, through atomic or molecular interactions between a substance and its environment (Kreith, Manglik and Bohn, 2010). Any solid is characterized by its thermal conductivity (k), which is a function of temperature, and reflects its ability to transfer heat through conduction. Combining Fourier's law for heat transfer and the 1st Law of Thermodynamics (heat transfer across a boundary surface + energy generated within the bound volume = change in storage energy of the bound volume), the general equation for conductive heat loss in Cartesian co-ordinates can be derived as:, where is the rate of energy addition across the volume, ? is the material density and c is the material specific heat. For the more restricted case of steady-state one-dimensional conduction across a homogenous wall, the equation can be reduced to, where T1 and T2 are the wall face temperatures, a is the heat transfer area (assumed to be normal to direction of transfer), L is the wall thickness and k is the wall thermal conductivity (Bejan and Kraus, 2003). Good conductors of heat, such as metals, have high thermal conductivity values, whereas heat insulators, such as non-metals, have low values. In petrochemical or other process industries, conductive heat loss to the surroundings from process piping is a major design issue. The rate of conductive heat transfer through a cylindrical pipe, per unit area, is given by,…… [read more]


Oxygen and Carbon Dioxide Carriage by Normal Blood View Paper

Essay  |  3 pages (839 words)
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Oxygen and Carbon Dioxide Respiration

Oxygen and Carbon Dioxide Blood Transport

Compare and Contrast Oxygen and Carbon Dioxide Respiration

Human aerobic respiration involves the oxidation of glucose to form carbon dioxide (CO2), or glycolysis, and the reduction of oxygen (O2) to water. This process produces the primary carrier of cellular energy, ATP (adenosine triphospate). Oxygen is therefore required to sustain life and carbon dioxide is a waste product that must be eliminated from the body to maintain the correct pH. This essay will review the physiology of gas exchange across the most important membranes during respiration in a normal healthy adult at sea level.

Alveolar Membrane

The partial pressures of O2 and CO2 in bronchial alveoli are 13.5 and 5.3 kPa, respectively (Table 1). Although the partial pressure of O2 in air is much higher at 21 kPa, the increased temperature inside the lungs, increased partial pressure of water vapor, and the mixing between the different gases during inhalation and exhalation reduce its effective pressure. By contrast, humans are essentially CO2 factories when we exhale a partial pressure of about 3.5 kPa into atmospheric air with a CO2 partial pressure near zero.

Table 1: Partial Pressures (kPa) by Anatomic Location

Membrane Boundary

PO2

PCO2

Alveolar Space

13.5

5.3

Alveolar Capillaries

13.3

5.3

Arterial Blood

12.5

5.3

Venous Blood

5.3

6.1

Tissue

< 5.3

> 6.1

Oxygen-depleted venous blood has a PO2 of about 5.3 kPa. At the interface between the thin alveolar bronchial and capillary membranes, the higher partial pressure of O2 inside the alveolar space leads to a rapid transfer of the gas across these membranes down a steep concentration gradient. Based on Henry's Law, the PO2 of the alveolar capillary blood as it exits the alveoli should be 13.5 kPa, but due to mixing with venous blood, the actual PO2 of arterial blood is about 12.5 kPa.

At the same time that oxygen is being transferred into alveolar capillaries, the metabolic waste product CO2 is being transferred out. Although the partial pressure gradient is much lower for this gas compared to that of oxygen, the much higher water solubility of CO2 compensates for the smaller partial pressure gradient.

Arterial Blood

The PO2 of arterial blood is about 12.5 kPa, which represents only about 3 ml/L of dissolved gas. This amount is insufficient to sustain human life. The vast majority of oxygen is transported inside erythrocytes by the hemoglobin protein, which consists of four subunits. Each subunit contains a heme or iron-porphyrin complex, which binds the oxygen molecule…… [read more]


Diffusion and Osmosis Experiment Lab View Paper

Term Paper  |  5 pages (1,863 words)
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This is due to the fact that the concentration of water inside the egg was less, and water flowed inside the egg from a region of higher concentration towards lower concentration. The egg present in O.5M glucose solution also gained mass as water flowed in the egg through the cell-membrane. This is due to the fact that the solution was hypotonic, and the concentration of water was higher outside the egg in comparison with its inside (Jeff, 2005). The egg in 1.5M glucose solution did not undergo any change in its size. This happened due to the fact that the concentration of water inside the egg and in the solution was the same. The egg present in 2M glucose reduced its size due to the fact that the concentration water inside the egg was higher than the solution, and thus the flow of water took place from the egg in to the 2M glucose solution.

Conclusion

The experiment conducted demonstrated the principle of osmosis and the effect of varying solution concentration on the process of osmosis and the size of eggs placed in the solutions. The experiment proved our first hypothesis wrong, as the size of the egg increased when placed in water. The size of the eggs increased due to the absorption of water by them. Our second hypothesis was correctly verified in the experiment as the size of egg also increased in this case due to water absorption as 0.5M solution was hypotonic. Our third hypothesis that size of egg will decrease in 1.5M solution proved wrong, as the mass of the egg remained the same during the observations taken at each interval, indicating that 1.5M solution was an isotonic one. Our fourth hypothesis was proved correct as the size of the egg decreased in 2M glucose solution as the solution was hypertonic. The experiment was thus successful in presenting the effect of varying concentration solution on osmosis.

References

Jeff, Sack. Osmosis and Diffusion, American Biology Teacher, 67.5 (2005), pp. 3-11, Retrieved

October 19, 2012, from http://www.eric.ed.gov/ERICWebPortal/search/detailmini.jsp?_nfpb=true&_&ERICExtSearch_SearchValue_0=EJ725843&ERICExtSearch_SearchType_0=no&accno=EJ725843

Lauren, M., Victor, S. & Lindsay, M. Exploring Osmosis and Diffusion in Cells: A

Guided-Inquiry…… [read more]


Science What Are the Steps View Paper

Book Review  |  2 pages (580 words)
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What is the structure of an atom? What particles are in the nucleus? What is their charge and mass? What particles are outside the nucleus? What's their charge and mass?

An atom is comprised of electrons, protons, and neutrons. Inside the nucleus are protons and neutrons. Protons have positive charges and neutrons are neutral. The atomic mass will equal the number of protons plus the number of neutrons in an atom. Outside the nucleus are the electrons, which have negative charges.

5. What is gained, lost or shared when a bond forms? How do you figure out the charge on an ion? How are ionic bonds different from covalent bonds? A covalent bond is really a shared pair of what? What about a double or triple bond? What is a polar bond?

Electrons are gained, lost or shared when a bond forms. The charge of an ion will be determined by the electron formation of the atoms being combined. In an ionic bond, the atoms are joined together by an oppositely-charged ions. Covalent bonds combine by sharing electrons. A covalent bond is thus really a shared pair of electrons. A double bond is a compound of two atoms and a triple bond is a joining of three. A polar bond is a covalent bond between two or more atoms when electrons are shared unequally.

6. What makes water special? How does hydrogen bonding in water effect cohesion? Temperature moderation? Density liquid vs. solid? Properties as a solvent?

Water is special because it is comprised of two hydrogen atoms and one oxygen atom. It is a polar covalent molecule. The hydrogen bonds that happen win water allow living things to exist in the water. The loose bonds between hydrogen atoms… [read more]


ICE What if Ice Did View Paper

Essay  |  2 pages (571 words)
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When this occurs, a lattice is formed that keeps the Oxygen atoms apart, and thus prevents the breakdown of the water structure into individual molecular pieces (Muzaffar, 2009).

Thus, water does become denser as it cools, but at approximately four degrees centigrade the matrices begin to form (University of Ohio, 2008). Water then begins to freeze and expand. Contrary to the conventional knowledge that is acquired from observation of most fluids as they turn to solids, water expands and becomes less dense rather than more.

The question of why ice floats is answered by this phenomenon. Ice, due to the expansion caused by a molecular need to remain a unified structure, is 9% less dense than the fluid water (University of Ohio, 2008). Because of this decreased density, ice can float in the surface of water. Flotation is a factor of disparate densities. The ice does not displace enough of the water to sink because the water can compensate for the density of the ice with its own. Conversely, a piece of solid steel will sink in water because it has a greater density than the water. For these reasons, ice, which is water, becomes less dense than its fluid self, and floats, much to the consternation of ancient scientists and observers, but not to the present wisdom gathered through technological superiority.

References

Lansing State Journal. (1998). Why does ice float? Retrieved November 13, 2010 from http://www.pa.msu.edu/sciencet/ask_st/040898.html

Muzaffar, I. (2009). Why does ice float on the surface of water? Islam & Science, 19(1).

University of Ohio. (2008). Why does ice float? Retrieved November 13, 2010 from http://www.units.muohio.edu/dragonfly/snow/icefloat.shtml… [read more]


Acidic and Basic Solutions and View Paper

Essay  |  2 pages (655 words)
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By adjusting the speed and depth of breathing, the brain and lungs are able to regulate the blood pH minute by minute." (The Merck Manual, 2014, p. 1) The kidneys also play a great role in impacting the pH of the blood because of their excretion of "excess acids or bases." (The Merck Manual, 2014, p. 1) However, these adjustments are made by the kidneys much slower than those made by the lungs. The body also has what are known as 'buffer systems' which is another mechanism the body uses in controlling the pH of the blood and guarding against acidity and alkalinity when it makes quick shifts. The pH of these buffer systems work in a chemical process that minimizes shifts in the pH of a solution through making an adjustment in the amount or proportion of the base and acid. The Merck Manual reports that the "The most important pH buffer system in the blood involves carbonic acid (a weak acid formed from the carbon dioxide dissolved in blood) and bicarbonate ions (the corresponding weak base)." (2014, p.1) There are reported to be two acid-base balance abnormalities including the following:

(1) Acidosis: The blood has too much acid (or too little base), resulting in a decrease in blood pH; and Alkalosis: The blood has too much base (or too little acid), resulting in an increase in blood pH. (The Merck Manual, 2014, p.1)

While these two acid-base abnormalities are not considered to be a disease they are what results from a wide array of disorders and are the result of "an imbalance in the production of acids or bases and their excretion by the kidneys." (The Merck Manual, 2014, p. 1)

In conclusion, the body has various mechanisms for correcting pH imbalances including the use of the lung, kidneys and the pH buffer system.

References

Overview of Acid-Base Balance (2014) The…… [read more]


Talking to the Man Who Discovered the Neutron View Paper

Interview  |  2 pages (600 words)
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James Chadwick

Interview with James Chadwick

You were awarded the Nobel Prize in 1935 for your discovery of the neutron. How did you get started on this process of discovery?

Well, it was a long road, believe it or not. And it all started quite by accident. You see, at Victoria University of Manchester, I meant to study maths, but by mistake I enrolled in the physics course -- ha ha -- and, well, of course the rest is history.

It certainly is! So you weren't born with a predilection for physics -- you just sort of fell into it.

Exactly. But once I was in -- I was hooked. After one year at university, I received a Heginbottom Scholarship to continue in physics. At that time, the department was under Ernest Rutherford. And, really, if one is going to be gracious, all of the honors and awards I received should also go to him, as it was he who set us all on the course of discovery.

Q: How so?

A: Well, Ernest gave us all research projects to do: mine was to find a way to compare radioactive energy measurements from two separate sources. Ernest had his own way in mind, but it didn't work. I knew it -- but I didn't want to say anything. We kept at it, however; and ultimately we came up with a way to measure gamma radiation. We published a paper on it in 1912. The year before I took first class honors. It was quite a time to be alive, I assure you.

Q: I believe it! And so what happened next?

A: Well, I took a Master of Science degree that year and received another scholarship which allowed me to study on the continent. Hans Geiger was doing research in…… [read more]


Model Admissions Essay for a Scholarship View Paper

Essay  |  5 pages (1,711 words)
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¶ … performance proves my merit and eligibility for this esteemed scholarship fund. As a member of the Honor Society and Dean's List, I have joined the rank of other high achieving students committed to perfecting our skills and honing our vision. My high GPA has remained consistent until recent personal crises. I have started and led extracurricular organizations and… [read more]