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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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 spectrophotometer and from the absorbance
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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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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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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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Melissa Carrithers AP Chemistry period 6 2-11-15 Determination of Ka of Weak Acids Purpose: The purpose of this lab is to find the strength of weak acids by determining the equilibrium constants for their ionization reactions in water. Is to use their measured pH values to calculate the pKa for the two unknown weak acids thus determining their identities. Hypothesis: If we neutralize a solution that contains a weak acid by adding a strong base to the solution‚ then the ions will be isolated and
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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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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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Determination of Equilibrium Constants Introduction Bromothymol blue is an indicator for many acid-base titrations. When adding different solutions within the indicator it is to react and change colors‚ in this experiment the different colors were blue‚ green‚ and yellow. In the following experiment‚ obtaining the absorbance levels for each one makes it possible to calculate the equilibrium constant. Materials and Methods For this specific experiment there are a few materials that are crucial
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Determination of an Equilibrium Constant Abstract: In this experiment‚ two reactions were run to determine the molar absorptivity and the equilibrium constant of FeSCN2+. The main principles used in this lab are equilibrium‚ LeChatlier’s Principle‚ Beer’s Law and Spectrocopy. The first reaction was run to completion using LeChatier’s Principle and the second reaction was run to equilibrium. A spectrophotometer was used to measure absorbances. Using a graph of absorbance versus concentration
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