Abstract This paper examines an experiment in which the kinetics of a nucleophilic substitution were observed, more specifically, the hydrolysis of t-butyl chloride. Furthermore, the paper discusses how the experiment confirms the kinetic order of the reaction. The materials and methods that were used are also discussed, as well as results of the experiment, which are shown in a table.
Table of Contents:
Introduction
Materials and Methods
Results
Discussion
Appendix
From the Paper "Sources of errors in this experiment are mainly normal human error, such as slight inaccuracies when using the pipettes (either when taking up or emptying the liquids). If there was also inconsistency (i.e. it was inaccurate for a different reason each time), then this could have a significant impact on the results. Also, deciding when the colour had completely changed (and thus, the reaction had gone to completion) depended on the lighting and the angle at which each experimenter stood from each flask. In terms of modifying the temperature, there was always a delay between attaining the target temperature and the thermometer reading, since the heat could not be perfectly spread out in the flask and it took time for the temperature to stabilize."
Abstract This paper presents an experiment in which two types of chromatography were used to separate a mixture of two dyes, methylene blue and fluorescein. The materials and methods that were used for the experiment are discusses as well as the results that were obtained. The results are presented in a table form.
Table of Contents:
Introduction
Materials and Methods
Results
Discussion
Additional Experiments
Appendix
From the Paper "Gel permeation chromatography is a type of size exclusion chromatography (SEC), where the mobile phase is an organic solvent and separation occurs based on size. (Davies, Johnson, 2007). It is used to determine the molecular weights of organic and biological molecules, such as nucleic acids and proteins. The stationary phase is a gel medium, (e.g. agarose, polyacrylamide, or dextran) and elution occurs under low pressure. The molecules of interest are often further separated based on charge, acidity/bascitiy and affinity to particular molecules. This technique is efficient because all the samples can be simultaneously loaded without deterring the elution process, or disrupting the biologically-active state of the different samples. (Davies, Johnson, 2007)."
Abstract This paper discusses an experiment that introduced several methods of differentiating between several types of organic compounds containing oxygen in their functional groups. Specifically, the experiment compares alcohols, ethers, aldehydes and ketones. The paper presents the results in a table and discusses them. Several figures are also presented.
Table of Contents:
Introduction
Materials and Methods
Results
Discussion
From the Paper "In this test, the rate of reaction is dependant upon the degree of substitution. This is because the Lucas reagent creates conditions that favour the SN1 mechanism, and therefore, the most substituted carbocation intermediate will react the fastest. Therefore, when the alcohol group is on a tri-substituted carbon, like in 3-methyl-1-buten-3-ol and 2-methyl-2-butanol, the reaction will be the fastest. In addition, 3-methyl-1-buten-3-ol contains a double bond, which enables resonance stabilization of the carbocation intermediate. 2-methyl-2-butanol lacks this feature, and is therefore, slightly slower. Since the alcohol group is on a di-substituted carbon in 3-methyl-2-butanol, the reaction will be even slower. 3-methyl-1-butanol will not even react since its alcohol group is on a mono-substituted carbon."
Abstract This paper presents and examines an experiment that identifies two unknown compounds based on their solubility, reactions with various organic and inorganic molecules and the melting point of certain synthesized derivatives containing the unknown. It describes the methods of the experiment and then presents and discusses the results obtained.
Table of Contents:
Introduction
Materials and Methods
Results
Discussion
From the Paper "The final step in the identification process was to make an acetamide derivative and its melting point to discover the primary amine (Organic Chemistry Lab Manual, 48-65). However, the recrystallization process did not yield any crystals, so the melting point of the actual unknown was measured. At 108-110oC, it would indicate 3-nitroaniline, which has a melting point of 113oC in literature (ChemIDplus Advanced). In addition, it does have a high molecular weight, 138.14 g/mol (ChemIDplus Advanced), as the solubility of its sulfonamide salt indicated (Organic Chemistry Lab Manual, 48-65). Finally, it is the only primary amine that is a yellow crystalline solid at room temperature (International Programme on Chemical Safety)."
Tags: solubility reaction, melting point, derivative
Abstract This paper discusses an experiment in which a Grignard reagent was synthesized and used to perform its unique function - nucleophilic addition to create a carbon-carbon bond. The paper describes the materials and methods used in the experiment. It then presents the results in a table and discusses the findings of the experiment.
Table of Contents:
Introduction
Materials and Methods
Results
Discussion
Appendix
From the Paper "Bis(diphenylmethyl) ether was more likely to form than any other side product because it is a result of nucleophilic substitution, which was the most likely mechanism to occur under the experimental conditions (Mazid and Palmer, 1975). The formation of biphenyl (as a result of self-coupling) was not possible during the synthesis of the Grignard reagent because during the Grignard reaction, coupling is avoided and precautions are taking to insure it does not occur. In order for the two carbons to couple, like in the alkylation by an acetylide ion (Wade, 433-445), the halide has to leave. However, the halide is an important component of any Grignard reagent, and if displaced by self-coupling (via nucleophilic substitution), the intended reaction could not occur. In other words, after the joining of the two equivalent alkyl groups, no further alkylationis possible, since the Grignard reagent would be destroyed (Wade, 433-445)."
Applies research into understanding changes in the chemistry and neurological pathways of the brain during motor and cognitive processes to the field of education.
Abstract This paper reviews literature that indicates that, particularly during the past five years, scientists have gained new insights into how the human brain works and what specific changes take place in the brain because of various motor and cognitive processes. The paper reports that these discoveries hold enormous promise for helping educators formulate improved methods of delivering educational services. The paper clarifies, however, that much research is needed still because the human brain is so enormously complex and every individual is unique. Despite these constraints, the writer believes that a fundamental paradigm shift in education will take place because truly individual educational approaches will be based on how different people learn at the molecular level.
Table of Contents:
Review and Discussion
Conclusion
From the Paper "These cost-effective techniques in educational services delivery have assumed new importance and relevance in recent years as American schools continue to struggle to meet the needs of an increasingly diverse student population. Therefore, identifying how young people learn by mapping the corresponding regions of the brain may provide better ways of teaching the approximately 80 percent of students who are not linear learners."
Abstract This paper looks at some of the chemicals contained in cosmetics and the dangers they pose to our health. The author explains that the U.S. Food and Drug Administration is extremely lax in their requirements with respect to cosmetic products and does not even have the authority to take a harmful product off the market unless the manufacturer voluntarily recalls that product. The author describes the use and effects of some of the most harmful ingredients, such as phthalates, lead and 1,4-Dioxane. The paper concludes that until the FDA approaches the EU's elevated health standards, American consumers are better off doing their own research before buying such products, and making an extra effort to make their concerns known to the government and demand changes.
From the Paper "In comparison with the European Union's Cosmetic Directive, the FDA is failing miserably in keeping up with personal care safety standards. Currently, the FDA has only prohibited 9 toxic ingredients from being included in cosmetics, while the EU has banned over 1,000. To aggravate the issue, the Cosmetics Ingredients Review, an organization that works with the FDA, "reviewed just 11 percent of the 10,500 cosmetic ingredients cataloged by the FDA, [while the] 89 percent of ingredients that remain unassessed are used in more than 99 percent of all products on the market" (Inspired Living)."
Tags: kohl, The Body Shop, ethics L'Oreal artificial environmental superficial warning
Abstract This paper describes proteins which are enzymes, and an experiment carried out to measure the optimal pH and temperature of the reaction between the enzyme alpha-amylase and starch. The author explains that enzymes are natural biochemical catalysts that selectively speed up chemical reactions. These enzymes can be greatly affected by the pH and temperature of the environment they are in and have optimal conditions in which they work most efficiently. Using light spectrometry and a variety of pH levels and temperatures to find a maximum efficiency of this protein, the author recorded absorbance levels to show the optimal pH and temperature of this reaction.
Outline
Abstract
Materials and Methods
Discussion
From the Paper "The experiment was done with variations in two different environmental factors, pH and temperature, and separate data were taken for each. For both experiments, a blank was prepared using 5mL distilled water and 0.1mL of I2KI indicator placed in a cuvette. This cuvette was used to set the spectrophotometer to zero absorbance with the wavelength set at 560nm. 0.1 mL of I2KI indicator was placed in 11 cuvettes for each experiment. For the temperature variation, six different water baths were made at 15, 30, 45, 55, 60, and 70 C. In each water bath a solution of 35mL starch and 35mL distilled water was mixed in an Erlenmeyer flask and allowed sufficient time to reach the given temperature."
Abstract This paper studies the theory that chemical reactions are the result of the collision between molecules. Also known as the collision model, the author explains how these collisions, when strong enough and with ambient environments, can cause kinetic energy. The paper also introduces the Arrhenius equation and explains how this equation measures the activation energy of a particular reaction and quantifies the collision model in a way that can be useful for scientists conducting experiments. Like any other equation, the paper describes the different experimental parameters that will have an impact on the product of the Arrhenius equation. The paper also demonstrates how the Arrhenius equation can be applied to other disciplines.
From the Paper "Not every collision between molecules will create new products. In fact, the vast majority of collisions do not because they are not strong enough to break the existing bonds, which are often quite strong between molecules. For the collision to be successful, the molecules have to be oriented in such a way that the activation energy is sufficient to generate a reaction in the substance in question. Temperature, the presence of catalysts, the concentration of the substance, and other factors affect activation energy. Also, the molecules within molecular bonds are also held together with different degrees of strength which affect the potential and kinetic energy released from collisions."
Abstract This paper provides a chemical perspective on the utilization of sunlight by plants for the conversion of carbon dioxide into organic matter, or photosynthesis. The author provides and explains the chemical equation of this process and explains how energy is converted from sunlight into a chemical form for plants to use as food. The paper also discusses briefly the greenhouse effect and suggests that it is possible that the science of chemistry may eventually provide an answer by arriving at some type of system or process which could effectively eliminate a good amount of the built-up carbon dioxide.
From the Paper "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."
Tags: greenhouse effect, carbon dioxide, energy conversion
Abstract The paper explains what chromium is, where it can be found and what its basic uses are.The paper also explains its advantages and disadvantages. In addition, the paper gives a case study in order to illustrate environmental exposure to public residence.
Outline:
Chromium
Chromium health
Toxic effect
Protection and Sampling
Industrial use
Environmental Exposure
Case study
Diagnosis Tests
Distribution of Chromium
Treatment
From the Paper "'Environmental hazards are rare these days because environmental regulations but they do occur. To illustrate environmental chromium exposure to public residence I will review a case study of a chromate-processing facility. When the waste from chromate-processing facilities is not disposed of properly, leaching from the topsoil and rocks allows it to enter bodies of water. Those that live near a chromate production facility can be exposed by airborne particulate through inhalation and by solution through ingestion if it seeps into their drinking water."
Abstract The paper discusses how nanotechnology is rife with challenges and risks; it could be used for the good of humanity or the demise of humanity itself. The paper offers a definition of nanotechnology and then examines the various social and economic concerns of individuals and groups regarding the emerging nanotechnology industry. According to the paper, despite challenges and risks posed by nanotechnology, it will indeed benefit mankind especially in the realm of manufacturing, industry and medicine.
From the Paper "Imagine 20 or 30 years in the future, you are driving in the countryside in your solar-powered turbo charged car, you are in your middle age and getting into retirement and suddenly you feel a throbbing pain in your chest. You activate the voice-controlled emergency device in your car and in two minutes, a mobile turbocopter whisks you away at the nearest hospital. In the treatment room, the "doctor" (it's actually an android) inject you with a liquid and thirty minutes after, the doctor announced that your triple bypass operation was a success and you can go home in three hours. You thank nanotechnology for those nanobots that made it possible for you to have a non-invasive surgery and be on your way without any complications."
Abstract The paper relates the method, procedure and observations of an experiment that uses the titration method to obtain accurate measurements of reactants in a chemical reaction. The paper provides the calculations of the concentration of sodium hydroxide and notes the sources of error that could have been prevented.
Outline:
Introduction
Materials
Procedure
Observations
Calculations
Sources of Error
From the Paper "A titration is a method used by people all over the world to obtain accurate measurements of both reactants in a chemical reaction. Generally some sort of indicator or pH scale is used to determine when the exact moment is that the reaction is complete. In doing this, the measurement of the titrant becomes more precise, and later calculations can be made at a more exact value. Phenolphthalein is used as an acid and base indicator as it causes a solution to change colour, either pink or colourless, as a solution becomes a base or an acid, respectively. The alteration between the pink colour and colourless is at around a pH of 9. When the pH is above approximately 9 then the phenolphthalein will cause a solution to become pink and when the pH is below approximately 9 the phenolphthalein will cause the solution to become colourless. A titrant is a solution placed in the buret, which is attached to a retort stand with a clamp."
A review of an experiment to determine how an activity series can be developed based on potential single displacement reactions with given metals and solutions.
Abstract The paper first lists the materials and procedures that were used in an experiment designed to determine how an activity series can be developed based on potential single displacement reactions with given metals and solutions. It then provides a table of the qualitative observations of the metals and solutions before the reaction occurred. The paper also presents a table of what happened during and after to the metals in the top row and solutions in the left column of a potential single displacement reaction when mixed together. The paper explains and discusses the conclusions drawn from these observations.
From the Paper "Observing potential single displacement reactions and examining to see if a chemical reaction actually occurred can develop an activity series. Based on the observations it can create an activity series because it is possible to see which metals are the most reactive. For example, in the experimental design that was used magnesium reacted with almost everything so it was evident that it should be near the top of the list. The metal that did not react with anything would mean that is the least reactive and it should be near the bottom of the activity series. To determine which metals will be in between the most and least reactive metal the individual reactions need to be looked at closer. The potential single displacement reaction can either occur or not occur based on which metal is higher in the activity series. This allows an activity series to be developed. Therefore, from most reactive to least reactive, the final activity series developed would be: magnesium, zinc, aluminum, iron and copper."
A review of an experiment that determined the reagent that would be limiting and the mass of the precipitate that would be formed in a chemical reaction.
Abstract The paper predicts the mass of precipitate that would be produced by the reaction of 2.00 g of strontium chloride with 2.00 g of copper (II) sulfate pentahydrate in 75 mL of water. The paper lists the materials utilized in this experiment, the procedure and the data collected. The paper provides the calculations used and shows how the prediction that was made turned out to be accurate.
From the Paper "The actual mass of the precipitate is 0.29 g. However, this is not entirely accurate. When removing the filter paper from the funnel the paper ripped, causing some of the precipitate to fall off onto the paper towel below. As a result, the observations are not entirely accurate because the mass of the filter paper and the precipitate should be higher. This also caused the calculation of the actual mass of the precipitate to be slightly lower than it should be. This was a human source of error, as it cannot be fixed after the error was made."
Tags: strontium, chloride, copper, (II), sulfate, pentahydrate, filter, paper
