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

Subtopic:  Thermochemistry |
 64%
Level 2: 60%+
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Based on the given data, select the correct statement:

vapH° (CCl4) = 30.5 kJ mol-1
fH° (CCl4) = - 135.5 kJ mol-1
aH° (C) = 715.0 kJ mol-1
aH° (Cl2)= 242 kJ mol-1

The enthalpy change for the following reaction would be:

 CCl4 (g)  C(g) + 4Cl (g) 

1. \(326 \mathrm{~kJ} \mathrm{~mol}^{-1}\) 2. \(1304 \mathrm{~kJ} \mathrm{~mol}^{-1}\)
3. \(-328 \mathrm{~kJ} \mathrm{~mol}^{-1}\) 4. \(-1304 \mathrm{~kJ} \mathrm{~mol}^{-1}\)
Subtopic:  Thermochemistry |
 67%
Level 2: 60%+
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For an isolated system with ∆U = 0, the ∆S value will be:

1. Positive 2. Negative
3. Zero 4. Not possible to define
Subtopic:  Classification of System, Extensive & Intensive Properties |
Level 3: 35%-60%
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The value of ∆G°  for the given reaction would be:
\( 2 \mathrm{~A}(\mathrm{~g})+\mathrm{B}(\mathrm{~g}) \rightarrow 2 \mathrm{D}(\mathrm{~g})\)
(Given: ∆U° = – 10.5 kJ and  ∆S° = – 44.1 J K–1)

1. 1.6 J 2. –0.16 kJ
3. 0.16 kJ 4. 1.6 kJ
Subtopic:  Gibbs Energy Change |
 53%
Level 3: 35%-60%
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Determine the value of  ∆G°, if the equilibrium constant for a reaction is 10:

(R = 8.314 J K-1 mol-1 ; T = 300 K)

1. \(-5.74 \mathrm{~kJ} \mathrm{~mol}^{-1}\)
2. \(-5.74 \mathrm{~J} \mathrm{~mol}^{-1}\)
3. \( +4.57 \mathrm{~kJ} \mathrm{~mol}^{-1}\)
4. \(-57.4 \mathrm{~kJ} \mathrm{~mol}^{-1}\)

Subtopic:  Gibbs Energy Change |
 77%
Level 2: 60%+
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At standard conditions, if the change in the enthalpy for the following reaction is –109 kJ mol
H2(g)+Br2(g)2HBr(g) and the bond energy of H2 and Br2 is 435 kJ mol–1 and 192 kJ mol–1 respectively, what is the bond energy (in kJ mol–1) of HBr?

1. 368 2. 736
3. 518 4. 259
Subtopic:  Thermochemistry |
 57%
Level 3: 35%-60%
NEET - 2020
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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
Subtopic:  Thermochemistry |
 83%
Level 1: 80%+
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The enthalpy of formation of COg, CO2g, N2Og , and N2O4g are –110 kJ mol-1, – 393 kJ mol-1, 81 kJ mol-1, 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. \(-\) \(345 . 4\) \(kJ\) \(\text{mol}^{- 1}\)
Subtopic:  Thermochemistry |
 77%
Level 2: 60%+
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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 \(24\) \(J\) \(\text{mol}^{- 1}\) \(K^{- 1}\))

1. \(1 . 07\) \(J\) 2. \(1 . 07\) \(kJ\)
3. \(106 . 7\) \(kJ\) 4. \(100 . 7\) \(kJ\)
Subtopic:  Thermodynamics' Properties and process |
 68%
Level 2: 60%+
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The reaction of cyanamide, NH2CN (s) with dioxygen, was carried out in a bomb calorimeter, and ∆U was found to be -742.7 kJ mol-1 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:

1. -741.3 kJ mol-1
2. + 753.9 kJ mol-1
3. + 772. 7 kJ mol-1
4. -845. 1 kJ mol-1

Subtopic:  Enthalpy & Internal energy |
 76%
Level 2: 60%+
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