7) According to the third law of thermodynamics,
A) the entropy increases for any spontaneous process.
B) the entropy of a perfectly ordered, crystalline substance is zero at 0 Kelvin.
C) energy is conserved in any transformation of matter.
D) the entropy of the universe increases for any spontaneous process.
8) Which of the three laws of thermodynamics states the criterion for spontaneity?
A) both the second and third laws of thermodynamics
B) the first law of thermodynamics
C) the third law of thermodynamics
D) the second law of thermodynamics
9) Calculate ΔS° for the following reaction.
N2(g) + 2 O2(g) → 2 NO2(g)
Species | S°, J/(K • mol)
N2 (g) | 191.5
O2 (g) | 205.0
NO2 (g) | 240.0
A) 15.5 J/K B) 636.5 J/K C) -156.5 J/K D) -121.5 J/K
10) For a spontaneous process
A) energy is conserved and the entropy of the system and surroundings increases.
B) both the energy and the entropy of the system and surroundings decrease.
C) the energy of the system and the surroundings decreases and the entropy of the system and surroundings increases.
D) energy and entropy are conserved.
11) At constant pressure and temperature, which statement is true?
A) All reactions for which K < 1 are spontaneous.
B) All reactions for which ΔH < 0 are spontaneous.
C) All reactions for which ΔS < 0 are spontaneous.
D) All reactions for which ΔG < 0 are spontaneous.
12) For the reaction 3 C2H2(g) → C6H6(l) at 25°C, the standard enthalpy change is -631 kJ and the standard entropy change is -430 J/K. Calculate the standard free energy change at 25°C.
A) -618 kJ B) -503 kJ C) -1061 kJ D) 948 kJ