SOLVED

31) The maximum quantity of energy available for useful work is: A) constant B) Gibbs energy C) the entropy D) the internal energy E) the enthalpy 32) The change in Gibbs energy for a reaction: A) = ΔH – TΔS B) = Q (heat) C) = ΔS + TΔH  D) = ΔS – TΔH E) = ΔH + TΔS 33) The Gibbs energy change for a reaction is -298 kJ. The reaction is therefore: A) exothermic B) irreversible C) spontaneous D) endothermic E) nonspontaneous 34) In a sealed container, the rate of dissolving is equal to the rate of crystallization. Therefore we would expect: A) ΔG < 0 B) ΔG > 0 C) ΔG = 0 D) ΔS = 0 E) must know ΔH to determine 35) If ΔG is positive for a certain reaction, then: A) the reaction is spontaneous. B) the reverse of the reaction is spontaneous. C) the system is in equilibrium. D) one would need to know the Kelvin temperature to determine spontaneity. E) there would be no reaction possible for a negative value. 36) A reaction is spontaneous if: I) ΔG is a negative value II) both enthalpy and entropy increase III) ΔH is negative and ΔS is positive IV) both enthalpy and entropy decrease V) ΔH is positive and ΔS is negative A) I and III B) I and II C) II and V D) III and IV E) II and IV 37) Which of the following combinations of signs for ΔH and ΔS will always result in a reaction being nonspontaneous? A) ΔH+, ΔS- B) ΔH-, ΔS+ C) ΔH-, ΔS- D) ΔH+, ΔS+ E) cannot determine without temperature 38) The following reaction is exothermic. 2N2O(g) → 2N2(g) + O2(g) This means the reaction: A) will be spontaneous at all temperatures B) will be spontaneous only at high temperature C) will be spontaneous only at low temperatures D) is not spontaneous at any temperature 39) The following reaction is endothermic. 2NH3(g) → N2(g) + 3H2(g) This means the reaction: A) will be spontaneous at high temperature B) will be spontaneous at low temperature C) is not spontaneous at any temperature D) is spontaneous at all temperatures 40) For an exothermic reaction to be nonspontaneous at high temperatures, the enthalpy must be ________ while the entropy is ________. A) positive, also positive B) positive, negative C) a relatively small negative value, also negative D) a relatively large negative value, positive E) a very large negative value, also negative