Question

30) At constant pressure and temperature, which statement is true? A) All reactions for which k < 1 are spontaneous B) All reactions for which AG are spontaneous C) All reactions for which AH<0 are spontaneous. D) All reactions for which AS <0 are spontaneous 11) 11) Consider the galvanic cell, Pb(s) IP20) Cu2+(a) Cu(s). Which one of the following changes to the cell would cause the cell potential to increase (ie, become more positive)? A) increase the mass of Pb(s) B) increase the [Pb2+ concentration decrease the mass of Pb(s) D) increase the Cu2+ concentration 12) 12) Predict the sign of AS of the system for both of the following 1 2 Cigraphite). O2(g) - 2018) II. C6H14() - CH1460 A) AS should be positive for I and positive for II. B) AS should be negative for I and positive for II. C) AS should be positive for I and negative for II. D) AS should be negative for I and negative for IL 13) If increases, A) AG increases and the reaction becomes less spontaneous. B) AG decreases and the reaction becomes less spontaneous. C) AG increases and the reaction becomes more spontaneous D) AG decreases and the reaction becomes more spontaneous 14) Which one of the following has the lowest standard molar entropy, S, at 25°C? A) C2H6(s) B) C14H30(s) C18H386) D) C7H16(1) 15) Based on the balanced chemical equation shown below, what volume of 0.250 MK2S2O3(aq), is needed to completely react with 24.88 mL of 0.125 M KI3(g)? 2S2O32- (aq) + 13- (aq) - S4062-(aq) +31-(aq) A) 12.4 mL B ) 6.22 mL C) 99.5 mL D) 24.9 mL

Answer 1

10)

K alone can’t decide whether the cell is spontaneous or not.

ΔG less than 0, implies the reaction is spontaneous.

ΔH and ΔS together can predict spontaneousity of the reaction.

Alone they cant.

Answer: C

11)

E = Eo - (0.0592/n) log {[Pb2+]/[Cu2+]}

To make E larger, we should decrease Pb2+ and increase Cu2+

Answer: D

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