Q. No.The standard enthalpy of combustion at of hydrogen, cyclohexene (C6H10), and cyclohexane (C6H12) are -241, -3800 and -3920 kJ mol-1, respectively. Calculate the standard enthalpy of hydrogenation of cyclohexene.
| 1. | -131 kJ mol-1 | 2. | -155 kJ mol-1 |
| 3. | -167 kJ mol-1 | 4. | -121 kJ mol-1 |
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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
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For the reaction:
N₂(g) + 3H₂(g) → 2NH₃(g) ; ΔᵣH° = –92.4 kJ mol⁻¹
What is the standard enthalpy of formation (ΔfH°) of NH₃(g)?
| 1. | -92.4 J (mol)-1 | 2. | -46.2 kJ (mol)-1 |
| 3. | +46.2 J (mol)-1 | 4. | +92.4 kJ (mol)-1 |
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Give 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
Enthalpy for the following reaction will be:
2. -243.6 kJ mol-1
3. -120.0 kJ mol-1
4. 553.0 kJ mol-1
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Consider the following reaction,
S + O2 SO2, H = – 298.2 kJ mole–1
SO2 + 1/2 O2 SO3, H = – 98.7kJ mole–1
SO3 + H2O H2SO4 , H = – 130.2 kJ mole–1
H2 + 1/2 O2 H2O, H = – 287.3 kJ mole–1
the enthalpy of formation of H2SO4 at 298 K will be:
| 1. | – 814.4 kJ mole–1 | 2. | + 814.4 kJ mole–1 |
| 3. | – 650.3 kJ mole–1 | 4. | – 433.7 kJ mole–1 |
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(298K) of methanol is given by the chemical equation:
1. \(\mathrm{C}(\text { diamond })+\frac{1}{2} \mathrm{O}_{2(\mathrm{~g})}+2 \mathrm{H}_{2(\mathrm{~g})} \rightarrow \mathrm{CH}_3 \mathrm{OH}_{(\mathrm{l})}\)
2. \(\mathrm{CH}_{4(\mathrm{~g})}+\frac{1}{2} \mathrm{O}_{2(\mathrm{~g})} \rightarrow \mathrm{CH}_3 \mathrm{OH}_{(\mathrm{g})}\)
3. \(\mathrm{CO}_{(\mathrm{g})}+2 \mathrm{H}_{2(\mathrm{~g})} \rightarrow \mathrm{CH}_3 \mathrm{OH}_{(\mathrm{l})}\)
4. \(\mathrm{C}(\text { graphite })+\frac{1}{2} \mathrm{O}_{2(\mathrm{~g})}+2 \mathrm{H}_{2(\mathrm{~g})} \rightarrow \mathrm{CH}_3 \mathrm{OH}_{(\mathrm{l})}\)
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| Assertion (A): | Combustion of all organic compounds is an exothermic reaction. |
| Reason (R): | The enthalpies of all elements in their standard state are zero. |
| 1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 3. | (A) is True but (R) is False. |
| 4. | (A) is False but (R) is True. |
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The enthalpy of formation of are –110 kJ , – 393 kJ , 81 kJ and 9.7 kJ \(\text{mol}^{- 1}\) respectively. The value of \(\left(\Delta\right)_{r} H\) for the following reaction would be:
\(\mathrm{N_{2} O_{4 \left(g\right)} + 3 CO{\left(g\right)} \rightarrow N_{2} O_{\left(g\right)} + 3CO_{2 \left(g\right)}}\)
| 1. | \(- 777 . 7\) \(kJ\) \(\text{mol}^{- 1}\) | 2. | \(\) \(+ 777 . 7\) \(kJ\) \(\text{mol}^{- 1}\) |
| 3. | \(\) \(+ 824 . 9\) \(kJ\) \(\text{mol}^{- 1}\) | 4. | \(-\) \(345 . 4\) \(kJ\) \(\text{mol}^{- 1}\) |
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The enthalpy of combustion of carbon to CO2 is –393.5 kJ mol-1. The amount of heat released upon formation of 35.2g of CO2 from carbon and dioxygen gas would be:
| 1. | –393.5 kJ mol–1 | 2. | –314.8 kJ mol–1 |
| 3. | +314.8 kJ mol–1 | 4. | –320.5 kJ mol–1 |
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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
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