In the reaction, both H and S are positive. The condition(s) under which the reaction would not be spontaneous are/is:
1. H>TS
2. S=H/T
3. H=TS
4. All of the above
The entropy change in the fusion of one mole of a solid melting at 27C is:
(the latent heat of fusion is 2930 J mol-1)
1. 9.77 JK-1mol-1
2. 19.73 JK-1mol-1
3. 2930 JK-1mol-1
4. 108.5 JK-1mol-1
1 mole of an ideal gas at 25 is subjected to expand reversibly ten times of its initial volume.
The change in entropy of expansion is:
1. 19.15 JK–1mol–1
2. 16.15 JK–1mol–1
3. 22.15 JK–1mol–1
4. None of the above
Determine the enthalpy change for the specified reaction:
2H2O2(l) 2H2O(l) + O2(g).
(Given the heat of formation of H2O2(l) and H2O(l) are –188 and –286 kJ/mol respectively)
1. | –196 kJ/mol | 2. | +196 kJ/mol |
3. | +948 kJ/mol | 4. | –948 kJ/mol |
Entropy decreases in which of the following reactions?
1. Boiling of egg
2. Combustion of benzene at 127C
3. Stretching of rubber band
4. Dissolution of sugar in water
Equilibrium is represented by:
1. H = 0
2. GTotal = 0
3. STotal = 0
4. E = 0
For exothermic reaction to be spontaneous (=negative) temperature must be -
1. | High | 2. | Zero |
3. | Constant | 4. | Low |
'The free energy change due to a reaction is zero when-
1. The reactants are initially mixed.
2. A catalyst is added
3. The system is at equilibrium
4. The reactants are completely consumed
For a given reaction, if ΔH = 35.5 kJ/mol and ΔS = 83.6 J/K·mol, at what temperature is the reaction spontaneous?
(Assume ΔH and ΔS remain constant with temperature.)
1. | T < 425 K | 2. | T > 425 K |
3. | All temperatures | 4. | T > 298 K |
The standard enthalpy of vaporisation vapH for water at 100C is 40.66 kJ mol-1. The
internal energy of vaporisation of water at 100C (in kJ mol-1) is-
(Assume water vapour to behave like an ideal gas)
1. +37.56
2. -43.76
3. +43.76
4. +40.66