The bond dissociation energies of and XY are in the ratio of 1 : 0.5 : 1. ∆H for the formation of XY is –200 kJ mol–1. The bond dissociation energy of X2 will be
1. 200 kJ mol–1
2. 100 kJ mol–1
3. 800 kJ mol–1
4. 400 kJ mol–1
The heat of combustion of carbon to CO2 is –393.5 KJ/mol. The heat changed 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. Go = – 2.30RT log K
4. Go = 2.30RT log K
Which of the following statements is correct for the spontaneous adsorption of a gas?
1. | ∆ S is negative and therefore, ∆ H should be highly positive |
2. | ∆ S is negative and therefore, ∆ H should be highly negative |
3. | ∆ S is positive and therefore, ∆ H should be negative |
4. | -∆ S is positive and therefore, ∆ H should also be highly positive |
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
is positive, and standard Gibb's energy change
decreases sharply with increasing temperature?
1. | C(graphite) + \(\frac{1}{2}\)O2(g) → CO(g) |
2. | CO(g) + \(\frac{1}{2}\)O2(g) → CO2(g) |
3. | Mg(s) + \(\frac{1}{2}\)O2(g) → MgO(s) |
4. | \(\frac{1}{2}\)C(graphite) + \(\frac{1}{2}\)O2(g) → \(\frac{1}{2}\)CO2(g) |
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)
Given the following reaction:
\(4H(g)\)→ \(2 H_{2}\)\((g)\)
The enthalpy change for the reaction is -869.6 kJ. The dissociation energy of the H-H bond is:
1. -869.6 kJ
2. +434.8kJ
3. +217.4kJ
4. -434.8 kJ
Standard entropies of X2, Y2 and XY3 are 60, 40 and 50JK-1mol-1 respectively. For the reaction
to be at equilibrium, the temperature should be:
1. 750 K
2. 1000 K
3. 1250 K
4. 500 K