find out the Entropy change.
1. From the following Ho and So values predict which of reactions I, II, and III will be spontaneous at 300ºC.

H (kJ)

S(J/K)

I

5.0

15

II

10.0

+20

III

5.0

30

A.I
B.II
C.III
D.I and II
E.II and III
2. From the following Ho and So values predict which of reactions I, II, and III would be spontaneous at 25ºC.

H (kJ)

S(J/K)

I

+10.5

+30

II

+1.8

113

III

126

+84

A.I
B.II
C.III
D.I and II
E.II and III
3. Work out the entropy change (J/mole.K) of the reaction. The molar entropies [S] are given in brackets
after each substance.
2 CuS(s) [66.5] + 3 O2(g) [205.1]" 2 CuO(s) [42.6] + 2 SO2(g) [248.2]
A.114.2
B.139.1
C.+33.0
D.+68.2
E.+166.7
4.. find out the entropy change (J/mole.K) of the reaction. The molar entropies [S] are given in
brackets after each substance.
3 NO2(g) [240.1] + H2O(l) [69.9] " 2 HNO3(aq) [146.4] + NO(g) [210.8]
A.286.6
B.212.4
C.156.3
D.+47.2
E. +156.3
5.Given Sº = 266.3 and the listed [Sº values] find out Sº for Fe3O4(s).
4 Fe3O4(s) [____] + O2(g) [205.1] " 6 Fe2O3(s) [87.4]
A.+111.1
B.+122.4
C.+134.1
D.+146.4
E.+159.6