Introduction: The main objective in this experiment is to determine if the claims made by the US government‚ regarding the spectrophotometric analysis of a copper penny hold true. Before 1982‚ the Lincoln cent contained 95% copper and 5% various mixtures of zinc and tin. As the cost of copper increased‚ the cost to produce the penny was more than the actual face value of the penny. This caused the US government to change the composition of the penny. The pennies we know today consist of a copper
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Title: Purification of Egg white protein Name: Michael Johnson Partner: David Logad & Nandita Date: 2nd 9th September 2004 Group: Thursday 11:30am - 3:30pm Introduction Salting Out In 1888 Hofmeister that it can be possible to dehydrate a protein by adding salt to the solution‚ salting out. When a protein in a aqueous solution it is surrounded by water‚ in fact there can be up to 0.35g of water tightly bound to 1g of protein (Simpson 2004). Also the effectiveness of the salting out
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sample 4 had the highest absorbance readings. There wasn’t any enzymes in the blank sample because there wasn’t any enzyme samples in that tube. Hence‚ the oxidation process did not occur and the products weren’t formed‚ not resulting in significant change of absorbance reading. On the other hand‚ all other sample showed enzyme activity through decreased in their absorbance. Samples 2 and 3 had the greatest activity compared to all samples. As we expected the absorbance level of the enzymes decreasing
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d. What is the effect of the product of 1st hydrolysis to the absorbance of the solution? Determination of Analytical Wavelength 2. Why should the solution with highest concentration be used to determine the analytical wavelength? 3. What was the analytical wavelength of FeSCN2+? 4. Relate the analytical wavelength to the color of the solution. Hint: Use a color wheel. 5. Why should we measure absorbance at the analytical wavelength? Calibration 6. What is the importance
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demonstrate the following proficiencies: 1. To determine the percentage of copper in brass by UV-visible spectroscopy. 2. Properly calibrate and use a spectrophotometer. 3. Convert percent transmittance to absorbance‚ and vice versa. 4. Construct a calibration curve relating absorbance and concentration for solutions of known concentrations. 5. Use a calibration curve to determine the concentration of an unknown solution. 6. Convert a molar concentration to a mass percent value. INTRODUCTION
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Determination of the activation energy of an enzyme catalysed reaction Introduction In this practical the aim for this experiment was to find out the catalytic power of alkaline phosphate‚ as well as the rate of reaction and the activation energy of p-nitrophenol phosphate. Enzymes are biological molecules that catalyse a chemical reaction. ‘Enzymes work by lowering the activation energy of a chemical reaction making it easier to proceed’ [1]. This allows molecules to have more energy therefore
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EXTRACTION AND CHARACTERIZATION OF PROTEINS Abstract Different techniques and principles for protein extraction and characterization were demonstrated in this experiment. Various proteins were extracted from different sources: 1.67 g yeast invertase‚ 1.03 g egg white albumin‚ and 5.15 g of milk casein. Activity assay for invertase was performed using Benedict’s test and the enzymes inverting action on sucrose was confirmed. Warburg-Christian Method and Bradford Assay were also employed to determine
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| | |Acid-Base Indicators: Spectroscopic Method of Determination of Ka | |Sahib Kaur | |
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crystal violet. Upon completion of the experiment it was seen that the rate of reaction of crystal violet turned out to be 1 which meant the reaction was first order with respect to crystal violet. This was deduced upon plotting the graph of ln Absorbance versus time of crystal violet and by drawing the line of best fit‚ which showed that the slope graph was 1 which is the rate of reaction. This whole experiment was based upon the equation: Rate= k [CV+] [OH-]‚ where k stands for the rate
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function like the body normally does and an experimental group that functions like the body would after consuming the Carb Cutter pill. Results were measured using levels of absorbance‚ the amount of light that shines through the solution‚ to determine how much starch is blocking the light shining through. The higher the absorbance levels‚ the higher the amount of starch in the solution. If there are still high amounts of starch in the solution‚ then this means that the
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