Study "Chemistry / Elements" Essays 56-68

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Stars Term Paper

… [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]


Model Admissions Essay for a Scholarship Essay

… ¶ … 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… [read more]


Talking to the Man Who Discovered the Neutron Interview

… 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]


Acidic and Basic Solutions Essay

… 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]


Oxygen and Carbon Dioxide Carriage by Normal Blood Essay

… 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 Term Paper

… 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]


Heat Loss Research Paper

… 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]


Biochemistry the Polypeptide Chain Configuration Article Review

… "

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]


Science What Are the Steps Book Review

… 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 Essay

… 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]


How the Process of a Battery Works Term Paper

… ¶ … 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]


Physical Phenomenon Term Paper

… 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… [read more]


Chemical Reactions Occur When Atoms Term Paper

… 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]

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