| 1. | \(\Delta_{\mathrm{r}} \mathrm{H}>0\) and \(\Delta_{\mathrm{r}} \mathrm{S}<0 \) | 2. | \(\Delta_{\mathrm{r}} \mathrm{H}<0\) and \( \Delta_{\mathrm{r}} \mathrm{S}>0 \) |
| 3. | \(\Delta_{\mathrm{r}} \mathrm{H}<0 \) and \(\Delta_{\mathrm{r}} \mathrm{S}<0 \) | 4. | \(\Delta_{\mathrm{r}} \mathrm{H}>0\) and \( \Delta_{\mathrm{r}} \mathrm{S}>0\) |
What is the value of ∆H for the reaction 2Al + Cr₂O₃ → 2Cr + Al₂O₃, knowing that the enthalpies of
formation of Al₂O₃ and Cr₂O₃ are –1596 kJ and –1134 kJ, respectively?
| 1. | –1365 kJ | 2. | 2730 kJ |
| 3. | –2730 kJ | 4. | –462 kJ |
Plants and living beings are examples of:
1. Isolated system
2. Adiabatic system
3. Open system
4. Closed system
Identify the false statement among the following.
| 1. | Temperature is a state function. |
| 2. | Work is a state function. |
| 3. | Change in the state is completely defined when the initial and final states are specified. |
| 4. | Work appears at the boundary of the system. |
Assume each reaction is carried out in an open container. For which of the following reactions will
∆ H be equal to ∆ U ?
1.
2.
3.
4.
Which of the following is not an endothermic reaction?
1. Combustion of methane
2. Decomposition of water
3. Dehydrogenation of ethane or ethylene
4. Conversion of graphite to diamond
Find the condition under which the standard Gibbs free energy change, ΔG°, is negative.
1. The surroundings perform no electrical work on the system.Hydrolysis of sucrose is given by the following reaction
Sucrose + H2O Glucose + Fructose
If the equilibrium constant (Kc) is 21013 at 300 K, the value of at the same temperature will be:
1. 8.314 J mol–1 K–1300 Kln (21013)
2. 8.314 J mol–1 K–1300 Kln (31013)
3. –8.314 J mol–1 K–1300 Kln (41013)
4. –8.314 J mol–1 K–1300 Kln (21013)
\(\underset {-10.7 \mathrm{JK}^{-1}{mol}^{-1}} {\mathrm{H}_{(a q)}^{+}+\mathrm{OH^{-}}_{(a q)}} \rightarrow \underset {+70 \mathrm{JK}^{-1} \mathrm{~mol}^{-1} } {\mathrm{H}_{2} \mathrm{O}_{(l)}} ~~ \mathrm{S}^{\circ}(298 \mathrm{~K})\)
Standard entropy change for the above reaction is:
1. 60.3 JK-1 mol-1
2. 80.7 JK-1 mol-1
3. -70 JK-1 mol-1
4. +10.7 JK-1 mol-1
Calculate the entropy change when one mole of liquid water at 373 K is converted into water vapour at the same temperature.
Given: Latent heat of vaporisation of water, ΔHᵥₐₚ = 2.257 kJ g⁻¹.
1. 105.9 JK-1mol-1
2. 107.9 JK-1mol-1
3. 108.9 JK-1mol-1
4. 109.9 JK-1mol-1