Practice Exam 1 - HOUR EXAM 1 Chemistry 030.102 Section 1 Prof Dagdigian NAME(Print clearly Last name first name middle initial jhed ID Calculators

Practice Exam 1 - HOUR EXAM 1 Chemistry 030.102 Section 1...

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Page 1 of 10 HOUR EXAM 1 NAME (Print clearly)______________________________ Chemistry 030.102 Last name, first name middle initial Section 1 – Prof. Dagdigian February 22, 2013 jhed ID__________________ Calculators allowed, but do not use programmable features. One sheet of 8 ½ × 11 in. paper with notes may be brought into the exam. Miscellaneous information: R = 8.31 J mol –1 K –1 T (K) = T (C) + 273 Units: 1 J = 1 V-C 1 A = 1 C/sec Faraday's constant F = 96485 C mol –1 w elec = – Q Δ E w elec,max = Δ G Δ G ° = – nF Δ E ° Δ E ° = E ° (cathode) – E ° (anode) Nernst equation: Δ E = Δ E ° – ( RT / nF ) ln Q = Δ E ° – (0.0592 V/ n ) log Q at 25 ° C Equilibirum constant: Δ E ° = ( RT / nF ) ln K = (0.0592 V/ n ) log K First-order kinetics: c = c 0 e kt Second-order kinetics: 1/ c = 1/ c 0 + 2 kt Activation energy: k = A e Ea / RT pH = –log[H 3 O + ] Equilibrium constant of water at 25 ° C: K = [H 3 O + ][OH ] = 10 –14 mol 2 L –2 You may use the space below or on page 9 for calculations, etc .
Name_________________________________ Page 2 of 10 1. Galvanic cells The following standard reduction potentials are available: Au3+(aq) + 3 eAu(s) E°= +1.498 V Zn2+(aq) + 2 eZn(s) E°= –0.762 V Consider an galvanic cell consisting of a zinc (Zn) electrode immersed a solution Zn(NO3)2and a gold (Au) electrode immersed in a solution containing Au(NO3)3, connected with a salt bridge Compute the standard potential difference for this cell. (a) Compute the standard potential difference for this galvanic cell. ΔE°= ______________________ V (b) Write a balanced equation describing the reaction occurring in this cell. (c) Compute the change in mass of the gold electrode after a current of 1.90 A flows through the cell for 30.0 minutes. The atomic weight of gold is 197.0 g mol–1Change in Au mass = ______________________ g Part and max points .
Name_________________________________ Page 3 of 10

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