Q. No.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 |
A gas is allowed to expand in a well insulated container against a constant external pressure of 2.5 atm from an initial volume of 2.50 L to a final volume of 4.50 L. Determine the change in internal energy U of the gas:
| 1. | +500 J | 2. | -500 J |
| 3. | -506 J | 4. | +515 J |
For the reaction, X2O4(l) 2XO2(g)
U = 2.1 kcal, S = 20 cal K-1 at 300 K. Hence, G is
1. 2.7 kcal
2. -2.7 kcal
3. 9.3 kcal
4. -9.3 kcal
If the enthalpy change for the transition of liquid water to steam is 30 kJ mol-1 at 27°C,
the entropy change for the process would be
1. 1.0 J mol-1 K-1
2. 0.1 J mol-1K-1
3. 100 J mol-1K-1
4. 10 J mol-1K-1
Which of the following options correctly describes the free expansion of an ideal gas under adiabatic conditions?
1. \(\mathrm{{q} \neq 0, ~~ \Delta {T}=0, ~~ {~W}=0} \)
2. \(\mathrm{{q}=0, ~~ \Delta {T}=0, ~~ {~W}=0} \)
3. \(\mathrm{{q}=0, ~~ \Delta {T}<0, ~~ {~W} \neq 0} \)
4. \(\mathrm{{q}=0, ~~ \Delta {T} \neq 0, ~~ {~W}=0} \)
Enthalpy change for the reaction,
4H(g) 2H2(g) is -869.6 kJ
The dissociation energy of H-H bond is
1. -869.6 kJ
2. + 434.8 kJ
3. +217.4 kJ
4. -434.8 kJ
Given the following bond energies:
| H-H bond energy | 431.37 kJ mol-1 |
| C=C bond energy | 606.10 kJ mol-1 |
| C-C bond energy | 336.49 kJ mol-1 |
| C-H bond energy | 410.50 kJ mol-1 |
Based on the data given above, enthalpy change for the following reaction will be:
1. 1523.6 kJ mol-1
2. -243.6 kJ mol-1
3. -120.0 kJ mol-1
4. 553.0 kJ mol-1
Which of the following are not state functions?
(I) q + W (II) q
(III) W (IV) H-TS
1. (I) and (IV)
2. (II), (III) and (IV)
3. (I) , (II) and (III)
4. (II) and (III)
| \(\small\text{(i)}~ \text{H}^+(aq) + \text{OH}^-(aq) \rightarrow \text{H}_2\text{O}(l); \quad \Delta H = -x_1 \text{ kJ mol}^{-1}\) |
| \(\small\text{(ii)}~ \text{H}_2(g) + \frac{1}{2}\text{O}_2(g) \rightarrow \text{H}_2\text{O}(l); \quad \Delta H = -x_2 \text{ kJ mol}^{-1}\) |
| \(\small\text{(iii)}~ \text{CO}_2(g) + \text{H}_2(g) \rightarrow \text{CO}(g) + \text{H}_2\text{O}(l); \quad \Delta H = -x_3 \text{ kJ mol}^{-1}\) |
| \(\small(iv)~ \text C_ 2\text H_ 5 ( g ) + \frac{5} {2} \text O_ 2 ( g ) = 2 \text C\text O_ 2 ( g ) + \text H_ 2 \text O ( l )~; ∆ H = - x_ 4~ kJ mol^ {- 1} \) |
Choose the correct option:
1. -x2 kJ mol-1
2. +x3 kJ mol-1
3. -x4 kJ mol-1
4. -x1 kJ mol-1
Identify the correct statement for the change of Gibbs free energy for a system (Gsystem) at constant temperature and pressure:
| 1. | If Gsystem > 0, the process is spontaneous |
| 2. | If Gsystem = 0, the system has attained equilibrium |
| 3. | If Gsystem = 0, the system is still moving in a particular direction |
| 4. | If Gsystem < 0, the process is not spontaneous |
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