For a given reaction, ∆H = 35.5 kJ mol^–1 and ∆S = 83.6 J K^–1 mol^–1. The reaction is spontaneous at:
(Assume that ∆H and ∆S  do not vary with temperature)
1. T > 425K
2. All temperatures
3. T > 298K
4. T < 425K

A gas is allowed to expand in a well-insulated container against a constant external pressure of 2.5atm from an initial volume of 2.50 L to a final volume of 4.50L. The change in internal energy U of the gas in joules will be:
1. –500J
2. –505J
3. –506J
4. –508J

The heat of combustion of carbon to CO₂ is –393.5 KJ/mol. The heat released upon the formation of 35.2 g of CO₂ from carbon and oxygen gas is:
1. –315 KJ
2. +315 KJ
3. –630 KJ
4. +630 KJ

The correct statement for a reversible process in a state of equilibrium is:
1. $∆$G = – 2.30RT log K
2. $∆$G = 2.30RT log K
3. $∆$G^o = – 2.30RT log K
4. $∆$G^o = 2.30RT log K

Given the reaction: 
X₂O₄(l) → 2XO₂(g) 
ΔU = 2.1 kcal, ΔS = 20 cal K^–1 at 300 K 
The value of ΔG is:
1. 2.7 kcal
2. –2.7 kcal
3. 9.3 kcal
4. –9.3 kcal

In which of the following reactions, the standard reaction entropy change
$(∆S^0)$ is positive, and standard Gibb's energy change
$(∆G^0)$ decreases sharply with increasing temperature?

The enthalpy of fusion of water is 1.435 kcal/mol. The molar entropy change for the melting of ice at 0 ^oC is:

1. 10.52 cal/(mol K)

2. 21.04 cal/(mol K)

3. 5.260 cal/(mol K)

4. 0.526 cal/(mol K)

The standard enthalpy of vaporization ${∆}_{\mathrm{vap}}{\mathrm{H}}^{\mathrm{o}}$ for water at 100 ^oC is 40.66 kJ mol^-1.
The internal energy of vaporization of water at 100 ^oC (in kJ mol^-1) is: 
(Assume water vapour behaves like an ideal gas.)

1. +37.56

2. -43.76

3. +43.76

4. +40.66