exam2 - CHEM 209 Final Exam 2 2/21/05 NAME: 1. (20 POINTS)...

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Unformatted text preview: CHEM 209 Final Exam 2 2/21/05 NAME: 1. (20 POINTS) Suppose a student is determining the total base content of an antacid tablet by performing a back titration. He/she weighs out a 0.3022-gram portion of a tablet whose total weight is 1.6335 grams, dissolves this in exactly 30.00mL of deionized water, and then adds exactly 20.00 mL ofO. 1000M HCl in order to bring the pH down to 2.2. This solution is then carefully back-titrated with 0.1050M NaOH, with 3.77 mL required to reach the equivalence point. Calculate the total base content (i.e., the number of rnrnoles of base contained) of the antacid tablet. SHOW ALL WORK CLEARLY. (“Formula weight of HCl = 36.46 granilmole; formula weight of NaOH = 40.00 gram/mole). 2. (30 POINTS) (a) Write the equation for Beer’s Law and define all the terms (including the correct units for each term). (b) The absorbance of a 1.0 x 10‘5M Fe(1, lO-pher‘1)32+ solution is measured at a wavelength of 510 nm and found to be 0.400. ‘What is the transmittance of this solution? SHOW YOUR WORK. (0) Suppose the solution in part (b) is diluted with deionized water by a factor of 2. What are the absorbance and transmittance of the diluted solution? SHOW YOUR WORK. 3. (20 POINT S) Sketch the shape of the titration cuives expected for the following ‘ titrations: (a) HCl with NaOH pH mL NaOH (b) KHP with NaOH . -pH A y mi. NaQI-I 4. (10 POINTS) What quantities are plotted on the x— and y-axes of: (a) a chromatogram? (b) a calibration curve? 5. (10 POINTS) Define the term “retention time”. What is its pn'ncipal use in GO analysm? ' 6. (1Q POINTS) Write the equilibrium constant expression for the following balanced chemical reaction: " 2+ 2- - ‘ 6Fe + Orzo? + 141-? ——-> 209* + We“ + 7H20 ...
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This note was uploaded on 09/12/2008 for the course CHEM 209 taught by Professor Greg during the Spring '07 term at University of Louisville.

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exam2 - CHEM 209 Final Exam 2 2/21/05 NAME: 1. (20 POINTS)...

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