71) What is Keq at 25°C of the spontaneous cell made from Ag+/Ag (0.80 V) and Cl2/Cl- (1.36 V) half cells? A) 1073 B) 10-10 C) 109 D) 1019 E) 10-19 72) What is Keq at 25°C of the spontaneous cell made from the Zn2+/Zn (-0.76 V) and Br2/2Br- (1.07 V) half cells? A) 10-6 B) 105 C) 1010 D) 10-11 E) 1061 73) Determine Keq at 25°C for the following reaction: Pb2+(aq) + Cu(s) ⇔ Cu2+(aq) + Pb(s) The half-reactions are: Pb2+(aq) + 2 e- ⇔ Pb(s)E° = -0.125 V Cu2+(aq) + 2 e- ⇔ Cu(s)E° = +0.337 V A) 2 × 1069 B) 2 × 10-16 C) 2 × 1016 D) 2 × 10-8 E) 6 × 107 74) For the reaction: Mg(s) + AgNO3(aq) → Ag(s) + Mg(NO3)2(aq) Ag+(aq) + e- → Ag(s)E° = 0.800 V Mg2+(aq) + 2 e- → Mg(s)E° = -2.356 V Determine ΔG°. A) -300.3 kJ/mol B) 304.5 kJ/mol C) 609.0 kJ/mol D) -304.5 kJ/mol E) -609.0 kJ/mol 75) What is ΔG° at 25°C for the reaction (not balanced): C3H8 + O2(g) → CO2(g) + H2O(l) if the standard cell potential is 1.092 V? A) -105 kJ B) -211 kJ C) 105 kJ D) -2107 kJ E) 211 kJ 76) What is the standard cell potential if the Gibbs energy is -2108 kJ in the reaction: C3H8 + O2(g) → CO2(g) + H2O(l) (not balanced)? A) -10.92 V B) 10.92 V C) 21.85 V D) -1.092 V E) 1.092 V 77) Calculate Ecell at 25°C for the following voltaic cell. Ksp for NiCO3 is 1.42 × 10-7. Ni(s) ? Ni2+(aq) [sat’d NiCO3(s)] ? Ni2+(aq) (0.010M) ? Ni(s) The half-reaction is: Ni2+(aq) + 2 e- → Ni(s) E° = -0.257 V A) +0.257 V B) -0.257 V C) 0.000 V D) +0.0844 V E) +0.0422 V 78) Find Ecell for the following voltaic cell at 25°C: Ti(s) ? Ti2+(aq) (0.550M) ? Sn2+(aq) (0.005 M) ? Sn(s) The half-reactions are: Ti2+(aq) + 2 e- ⇔ Ti(s)E° = -1.630 V Sn2+(aq) + 2 e- ⇔ Sn(s)E° = -0.137 V A) 1.372 V B) 1.707 V C) 1.646 V D) 1.433 V E) -1.646 V 79) Determine Ecell at 25°C for the following reaction at 25°C: Al ? Al3+(0.435 M) ? Sn2+(2.12 × 10-3 M) ? Sn 3 Sn2+ + 2 Al(s) → 2 Al3+ + 3 Sn(s) Al3+ + 3 e- → Al(s)E° = -1.676 V Sn2+ + 2 e- → Sn(s)E° = -0.137 V A) 1.227 V B) 1.611 V C) 1.562 V D) 1.487 V E) 1.467 V 80) What is Ecell at 25°C of the spontaneous cell made from Ag+/Ag (0.80 V) and Cl2/Cl- (1.36 V) half cells if [Ag+] = 10-2 and [Cl-] = 10-4 with P(Cl2) = 1.1 atm? A) 0.65 V B) 0.38 V C) 0.74 V D) 0.92 V E) 0.20 V