Question 1
Calculate Δ
rG° for the reaction Cu(s) + H
2O(g) → CuO(s) + H
2(g) at 500 K.
ΔfH° (kJ/ mol) S° (J/mol K) Cu(s) 0 33.3
H
2O(g) -241.8 188.7
CuO(s) -155.2 43.5
H
2(g) 0 130.6
◦ 231.8 kJ
◦ -135.4 kJ
◦ -58.6 kJ
◦ 110.6 kJ
◦ 86.74 kJ
Question 2
Choose the correct statements concerning entropy.
I) Following the mixing of two gases, Δ
S is positive.
II) Entropy is a thermodynamic property related to the degree of disorder.
III) If the temperature of a gas is decreased, Δ
S is positive.
IV) Molecules in the liquid state have higher entropy than the same molecules in the gaseous state.
◦ I and III
◦ I, II, III
◦ I and II
◦ I, II, IV
◦ II and III