The standard enthalpy of the formation of CH3OH(l) from the following data is:
\(\small{\mathrm{CH}_3 \mathrm{OH}_{(l)}+\frac{3}{2} \mathrm{O}_2(\mathrm{g}) \rightarrow \mathrm{CO}_2(\mathrm{g})+2 \mathrm{H}_2 \mathrm{O}_{(l)} \text {; }}\) \( \Delta_{\mathrm{r}} \mathrm{H}^{\circ}=-726 \mathrm{~kJ} \mathrm{~mol}{ }^{-1}\) |
\(\small{\mathrm{C}(\mathrm{s})+\mathrm{O}_2(\mathrm{g}) \rightarrow \mathrm{CO}_2(\mathrm{g}) \text {; } }\) \(\Delta_{\mathrm{c}} \mathrm{H}^{\circ}=-393 \mathrm{~kJ} \mathrm{~mol}{ }^{-1}\) |
\(\small{\mathrm{H}_{2(\mathrm{g})}+\frac{1}{2} \mathrm{O}_{2(\mathrm{g})} \rightarrow \mathrm{H}_2 \mathrm{O}_{(l)} \text {; } } \) \(\Delta_{\mathrm{f}} \mathrm{H}^{\circ}=-286 \mathrm{~kJ} \mathrm{~mol}^{-1}\) |
1. | −239 kJ mol−1 | 2. | +239 kJ mol−1 |
3. | −47 kJ mol−1 | 4. | +47 kJ mol−1 |
For an isolated system with ∆U = 0, the ∆S value will be-
1. | Positive | 2. | Negative |
3. | Zero | 4. | Not possible to define |
For the reaction at 298 K,
2A + B → C
ΔH = 400 kJ mol−1 and ΔS = 0.2 kJ K−1 mol−1. The reaction will become spontaneous at-
1. 1500 K
2. 2000 K
3. 100 K
4. 1900K
For the reaction 2A(g) + B(g) → 2D(g) ; ∆U° = - 10.5 kJ and ∆S° = - 44.1 J K-1, the value of ∆G° for the given reaction would be-
1. 1.6 J
2. -0.16 kJ
3. 0.16 kJ
4. 1.6 kJ
The equilibrium constant for a reaction is 10. The value of will be:
( )
. The standard enthalpy of formation of gas in the above reaction would be-
1. | -92.4 J (mol)-1 | 2. | -46.2 kJ (mol)-1 |
3. | +46.2 J (mol)-1 | 4. | +92.4 kJ (mol)-1 |
The enthalpy of formation of are
–110 kJ , – 393 kJ , 81 kJ and 9.7 kJ respectively.
The value of for the reaction would be-
The amount of heat needed to raise the temperature of 60.0 g of aluminium from 35°C to 55°C would be -
(Molar heat capacity of Al is )
The reaction of cyanamide, with dioxygen, was carried out in a bomb calorimeter, and ∆U was found to be at 298 K.
\(\small{\mathrm{NH}_2 \mathrm{CN}(\mathrm{s})+\frac{3}{2} \mathrm{O}_2(\mathrm{g}) \rightarrow \mathrm{N}_2(\mathrm{g})+\mathrm{CO}_2(\mathrm{g})+\mathrm{H}_2 \mathrm{O}(\mathrm{l})}\)
The enthalpy change for the reaction at 298 K would be -