- 1(current)
Q. No.Three thermochemical equations are given below:
Based on the above equations, find out which one of the relationships given below is correct :
| (i) | C(graphite) + O2(g) \(\rightarrow\) CO2(g); \(\Delta_{r}\)H° = x kJ mol–1 |
| (ii) | Cgraphite + 1/2 O2(g) \(\rightarrow\) CO(g); \(\Delta_{r}\)H° = y kJ mol–1 |
| (iii) | CO(g) + 1/2 O2(g) \(\rightarrow\) CO2(g); \(\Delta_{r}\)H° = z kJ mol–1 |
Based on the above equations, find out which one of the relationships given below is correct :
| 1. | z = x + y | 2. | x = y + z |
| 3. | y = 2z – x | 4. | x = y – z |
Subtopic: Hess's Law |
78%
From NCERT
NEET - 2013
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Which relationship is correctly associated with the following reactions?
NO(g) → \(\frac{1}{2}\)N2(g) + \(\frac{1}{2}\)O2(g) \(\Delta \text H^\circ_1\)
2NO(g) → N2O(g) + \(\frac{1}{2}\)O2(g) \(\Delta \text H^\circ_2\)
1. \(\Delta \text H^\circ_1~=~\Delta \text H^\circ_2\)
2. \(\Delta \text H^\circ_f\) for NO(g) = \(\Delta \text H^\circ_1\)
3. \(\Delta \text H^\circ_f\) for N2O(g) = \(\Delta \text H^\circ_2\)
4. \(\Delta \text H^\circ_f\) for N2O(g) = \(\Delta \text H^\circ_2-\Delta \text 2H^\circ_1\)
NO(g) → \(\frac{1}{2}\)N2(g) + \(\frac{1}{2}\)O2(g) \(\Delta \text H^\circ_1\)
2NO(g) → N2O(g) + \(\frac{1}{2}\)O2(g) \(\Delta \text H^\circ_2\)
1. \(\Delta \text H^\circ_1~=~\Delta \text H^\circ_2\)
2. \(\Delta \text H^\circ_f\) for NO(g) = \(\Delta \text H^\circ_1\)
3. \(\Delta \text H^\circ_f\) for N2O(g) = \(\Delta \text H^\circ_2\)
4. \(\Delta \text H^\circ_f\) for N2O(g) = \(\Delta \text H^\circ_2-\Delta \text 2H^\circ_1\)
Subtopic: Hess's Law |
64%
From NCERT
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Given the standard enthalpies of the gas-phase reactions of hydrogen sulphide, what is the standard enthalpy of reaction for the gas-phase combustion of carbon disulphide?
1. –450.4 kJ mol–1
2. –586.0 kJ mol–1
3. –968.6 kJ mol–1
4. –1104.2 kJ mol–1
| Reaction | Δ Hºrxn, kJ mol–1 |
| H2S + 1.5O2 → SO2 + H2O | –518.2 |
| 2H2S + CO2 → CS2 + 2H2O | 67.8 |
| CS2 + 3O2 → CO2 + 2SO2 | ??? |
2. –586.0 kJ mol–1
3. –968.6 kJ mol–1
4. –1104.2 kJ mol–1
Subtopic: Hess's Law |
73%
From NCERT
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The combustion of one mole of benzene takes place at 298 K and 1 atm. After combustion, CO2(g) and H2O (l)
are produced and 3267.0 kJ of heat is liberated.
The standard enthalpy of formation, ∆fH⊖ of benzene is:
(Standard enthalpies of formation of CO2(g) and are –393.5 kJ mol–1 and – 285.83 kJ mol–1 respectively.)
1. 54. 24 kJ mol–1
2. 48. 51 kJ mol–1
3. 66. 11 kJ mol–1
4. 15. 21 kJ mol–1
Subtopic: Hess's Law |
67%
From NCERT
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