Date Performed: September 9 ‚2011 SPECTROPHOTOMETRIC DETERMINATION OF THE ACID DISSOCIATION CONSTANT OF METHYL RED M.C. Caligagan ‚M.N.Q. Tolentino and M.Q. Clores Institute of Chemistry‚ College of Science University of the Philippines‚ Diliman‚ Quezon City‚ Philippines Received :September 21‚2011 ABSTRACT This experiment aims to determine the acid dissociation constant value of Methyl Red by means of spectrophotometry. Ten samples were spectrophotometrically analyzed under a UV-Vis
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EXPERIMENT 2 ACID DISSOCIATION CONSTANT OF AN INDICATOR DYE OBJECTIVES Using spectrophotometric method: determine the wavelengths at which the acid and base forms of the dye in aqueous medium exhibit maximum absorption; determine the molar absorptivities of the acid and base forms of the dye and estimate an unknown concentration of the dye in solution using the Beer-Lambert’s Law; and determine the acid dissociation constant of the indicator dye. THEORY The absorption or reflection of
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mixtures and find the dissociation constant of acetic acid Chemistry (HL) Research Question: To determine the pH of various mixtures of sodium acetate and acetic acid in an aqueous solution and hence to find the dissociation constant of the acetic acid. Background: The mixture of sodium acetate and acetic acid in aqueous solution is a buffer solution. Buffer solutions are the solutions which resist a sudden change in the pH due to addition of small amounts of strong acid or base. An acidic buffer
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Synthesis of Salicylic Acid and Potentiometric Determination of its Purity and Dissociation Constant ------------------------------------------------- Abstract The purpose of the study is to synthesize salicylic acid from the ester‚ methyl salicylate‚ and determine the acid’s dissociation constant and purity. The ester was converted to salicylic acid by base hydrolysis. The products were refluxed and recrystallized‚ to ensure maximum purity‚ and filtered‚ dried‚ and weighed. The melting point
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DETERMINING THE EQUIVALENT MASS AND DISSOCIATION CONSTANT OF AN UNKNOWN WEAK ACID BY TITRIMETRY INTRODUCTION Acids are substances that donate hydrogen ions and bases are substances that accept hydrogen ions. Acids and bases react with each other by transferring hydrogen ions. One way to distinguish an acid is by its equivalent mass‚ which is the number of grams of the acid needed to transfer one mole of hydrogen ion to a base. For a monoprotic acid‚ which only transfers one hydrogen ion‚ its
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Methyl Red Voges-Proskauer Test Questions A.What is meant by the term biochemical profile? Biochemical profile is a variety of biochemical tests. These various tests are used to measure the constituents of plasma and serum in blood. B.What metabolic end product does the MR test for? The metabolic end product MR tests for are the different bacteria’s related to their individual patterns of glucose metabolism. C.What does an orange color indicate as a result for an MR test? An orange color as a result
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The purpose of the Weak Acid Dissociation experiment is to determine the dissociation constant of a weak acid experimentally by using acid-base titration with a strong base and stoichiometry. An acid-base titration is a method by which a basic (or acidic) solution of unknown concentration is reacted with an acidic (or basic) solution of known concentration. (1) The pH in acid-base titration is measured using a pH meter or color changing indicator‚ such as phenolphthalein‚ as the known solution is
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Experiment # 4: Dissociation Constant Weak Acids Introduction: The dissociation constants of weak monoprotic acids were determined with the aid of a buffer and pH meter. Experiment: This experiment was performed according to the procedures as provided in the Chemistry 111B laboratory manual: Po‚ Henry and Senozan‚ N. "General Chemistry Experiments Chemistry 111B"‚ 8th Ed.‚ 2004 Hayden-McNeil Publishing‚ pp 80-88. To determine the dissociation constants of weak monoprotic acids (HX and HY)‚ a buffer
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Experiment #5: Esterification of Methyl Benzoate from Benzoic Acid October 28‚ 2010 Abstract: This experiment was conducted to synthesize methyl benzoate from benzoic acid and methanol by using the Fischer esterification method. Methanol (12.5ml) and Benzoic acid (4.9 grams) are heated together in the presence of concentrated sulfuric acid (1.5ml) until equilibrium is achieved. A reflux apparatus is set up for 1 hour to carry out the reaction at the boiling point of the solvent (Methanol
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Methyl Red and Voges-Proskauer Test The Methyl Red test shows which bacteria are creating stable acids through mixed acid fermentation of glucose. This helps to identify enteric bacteria by examining how they metabolise glucose. Every enteric bacteria first produces pyruvic acid from metabolism of glucose. A methyl red positive enteric bacteria‚ uses the mixed acid pathway when breaking down pyruvic acid to different acids‚ like lactic‚ acetic‚ and formic acids. The Voges-Proskauer test determines
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