Q. No.\(\mathrm{OF_{2(g)} + H_2O_{(g)}\rightarrow O_{2(g)} + 2HF_{(g)}; ~~~~\Delta H^o=-310kJ}~\)
1. –312.47 kJ
2. –125.03 kJ
3. –350 kJ
4. –156 kJ
Assuming the water vapour to be a perfect gas. When 1 mol of water at 100°C and 1 bar pressure is converted to ice at 0°C, the change in internal energy is-
(The enthalpy of fusion of ice = 6.00 kJ mol-1 , heat capacity of water = 4.2 J/g°C)
1. 13.56 kJ mol-1
2. -12.16 kJ mol-1
3. -13.56 kJ mol-1
4. 12.16 kJ mol-1
The enthalpy of sublimation of a substance is equal to:
1. Enthalpy of fusion + Enthalpy of vaporization
2. Enthalpy of fusion
3. Enthalpy of vaporization
4. Twice the enthalpy of vaporization
1. Ca(s) + \(\frac{1}{8}\) S8(s, rhombic) + \(\frac{3}{2}\) O2(g) → CaSO3(s)
2. 8Ca(s) + S8(s) + 12O2(g) → 8CaSO3(s)
3. 8Ca(s) + S8(g) + 12O2(g) → 8CaSO3(s)
4. CaO(s) + SO2(g) → CaSO3(s)
\(\mathrm{OF_2 + H_2O \rightarrow O_2+2HF?}\)
(Given the bond energies of \(\mathrm{O-F, O-H, H-F}\) and \(\mathrm {and~O=O}\) as 44, 111, 135, and 119 kcal mol–1, respectively)
| 1. | –222 kcal | 2. | –88 kcal |
| 3. | –111 kcal | 4. | –79 kcal |
The enthalpies of elements in their standard states are taken as zero. The enthalpy of formation of a compound is-
| 1. | Generally negative | 2. | Always positive |
| 3. | Zero | 4. | Never negative |
\(\mathrm{2H_2(g) + O_2(g) \rightarrow 2H_2O(g) \Delta_rH^\circ = -483.64 kJ. }\)
What is the enthalpy change for the decomposition of one mole of water?
| 1. | 120.9 kJ | 2. | 241.82 kJ |
| 3. | 18 kJ | 4. | 100 kJ |
\(CO_2(g) + H_2(g) \rightarrow CO(g) + H_2O (g)\)
(\(\Delta_f H^o\) for \(CO_2(g) , CO(g) , ~and ~H_2O (g) \) are –393.5, –110.5.0, and –241.8 kJ/mol respectively.)
1. –41.2
2. 41.2
3. 524.1
4. –262.2
1. 157 kJ mol-1
2. –1574 kJ mol-1
3. –394 kJ mol-1
4. 32.8 kJ mol-1
The standard enthalpies of the formation of NO2(g) and N2O4(g) are 8 kcal mol–1 and 2 kcal mol–1 respectively. The heat of dimerization of NO2 in the gaseous state is:
| 1. | 10 k cal mol–1 | 2. | 6.0 k cal mol–1 |
| 3. | –14 k cal mol–1 | 4. | –6.0 k cal mol–1 |
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