Learning how to Prepare Buffers of Various pH levels and Preparation of Acetate Buffer. Introduction A buffer is a solution having the capacity to resist changes in pH levels. Mostly a buffer consists of a weak acid and a salt of strong base or a weak base and a conjugate salt of strong acid e.g. acetate buffer is the most common buffer in which equimolar mixture of acetic acid and sodium acetate solution is used. CH3COOH CH3 COO - + H+ CH3COONa CH3COO - + Na+ Buffers are divided into 2 parts
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substrate. Variables: Independent: pH‚ enzyme concentration‚ substrate concentration and enzymatic activity. Dependent: the reaction rate Control variable: temperature and amount of substrates and enzymes added. Materials: Phosphate Buffers Beaker Catechol Potato Juice Parafilm Test Tubes Procedure: To study the effect of temperature: 1. Three different test tubes where filled with 3mL of phosphate. 2. They were set in three different temperature settings. First tube was
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Research Question How will the addition of different pH buffers to amylase affect the rate of starch digestion measured using starch and iodine? Introduction Amylase is an enzyme found in human saliva and pancreas. It is the digestive enzyme that is needed to breakdown starch molecules. Amylase must be kept at certain conditions to function at its optimum level. This experiment will explore the effect of pH (1‚ 4‚ 7‚ 10‚ and 14) on the function of amylase by using starch and iodine. Usually
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During the preparation of the 0.100M Tris buffer‚ the calculated amount of ingredients brought the solution to a pH of 7.0‚ but the desired pH was 7.50. Discrepancies between the theoretically calculated amounts and the actual measured amounts of ingredients are likely to be the biggest source of error. Dilution affected our 0.0100M Tris buffer by decreasing its pH. The buffer was originally set to a pH of 7.48‚ but the pH gradually moved down by a pH unit of about 0.1 after each dilution. This is
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Chemistry102 5/7/2013 Lecture Presentation Chapter 17 Additional Aspects of Aqueous Equilibria John D. Bookstaver St. Charles Community College Cottleville‚ MO © 2012 Pearson Education‚ Inc. Common Ion Effect HA(aq) + H2O(l) ⇔ A−(aq) + H3O+(aq) • Adding a salt containing the anion NaA‚ which • is the conjugate base of the acid (the common ion)‚ shifts the position of equilibrium to the left This causes the pH to be higher than the pH of the acid solution 9lowering the H3O+ ion concentration
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single drops of iodine solution in rows on the tile. * Label a test tube with the pH to be tested. * Use the syringe to place 2 cm3 of amylase into the test tube. * Add 1 cm3 of buffer solution to the test tube using a syringe. * Use another syringe to add 2 cm3 of starch to the amylase/ buffer solution. Start the stop clock and leave it on throughout the test. Mix using a plastic pipette. * After 10 seconds‚ use the plastic pipette to place one drop of the mixture on the first
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was added to the solution. By performing this experiment‚ it was found that with increasing amounts of buffer in the prepared solutions there was better resistance against pH changes. This was because the strong acid or base was converted to it’s weak conjugate. The solution with little or no buffer had no resistance to pH changes. The Irresistible
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DeKroon et al. DIGE-based PTMs Analysis of protein post-translational modifications using DIGE-based proteomics Robert M. DeKroon‚ Jennifer B. Robinette‚ Cristina Osorio‚ Sun Yong Jeong‚ Eric Hamlett‚ Mihaela Mocanu and Oscar Alzate Summary Difference gel electrophoresis (DIGE) is most often used to assess relative changes in the expression levels of individual proteins in multiple complex samples‚ and this information is valuable in making inferences about relative protein activity. However
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3 Dropper 12 Timer 12 Labels 36 Thermometer 12 Water bath 3 Enzyme source eg. Radishes/celery Hydrogen peroxide Range of buffer solutions pH paper Washing up liquid Disposable gloves The apparatus for this experiment lends itself to being pre-prepared in a ‘box of equipment’ – see Section 1. Advance preparation Prepare buffer solutions. Obtain fresh celery. Advance chemical preparation (a) Hydrogen peroxide (Prepares 250 ml of 1M/’12 vol’ solution) Wearing
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| Buffer A | Buffer B | Mass of NaC2H3O2 used to prepare buffer (grams) | | | Volume of buffer prepared (mL) | 100.0 | 100.0 | Molar concentration of HC2H3O2 in buffer (M) | 0.1 | 1.0 | Initial pH of buffer | | | Volume of 0.5 M NaOH to raise pH by 2 units (mL) | | | Volume of 0.5 M HCl to lower pH by 2 units (mL) | | | Volume of 0.5 M NaOH at equivalence point (mL) | | | Data Analysis 1. Write reaction equations to explain how your acetic acid-acetate buffer reacts
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