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Page 1 of 10HOUR 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–1K–1 T(K) = T(C) + 273Units: 1 J = 1 V-C 1 A = 1 C/secFaraday's constant F= 96485 C mol–1welec= –QΔEwelec,max= ΔG ΔG°= –nFΔE°ΔE°= E°(cathode) – E°(anode) Nernst equation: ΔE= ΔE°– (RT/nF) lnQ= ΔE°– (0.0592 V/n) logQat 25 °C Equilibirum constant: ΔE°= (RT/nF) lnK= (0.0592 V/n) logKFirst-order kinetics: c= c0e–ktSecond-order kinetics: 1/c= 1/c0+ 2kt Activation energy:k= Ae–Ea/RTpH = –log[H3O+] Equilibrium constant of water at 25 °C: K= [H3O+][OH–] = 10–14mol2L–2You 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 e–→Au(s) E°= +1.498 V Zn2+(aq) + 2 e–→Zn(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 .
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