The correct thermodynamic conditions for a spontaneous reaction at all temperatures is:
1. H > 0 and S< 0
2. H < 0 and S> 0
3. H < 0 and S< 0
4. H > 0 and S = 0

Subtopic:  Gibbs Energy Change |
 85%
Level 1: 80%+
NEET - 2016
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The heat of combustion of carbon to CO2 is –393.5 KJ/mol. The heat released upon the formation of 35.2 g of CO2 from carbon and oxygen gas is:
1. –315 KJ
2. +315 KJ
3. –630 KJ
4. +630 KJ

Subtopic:  Thermochemistry |
 75%
Level 2: 60%+
NEET - 2015
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The correct statement for a reversible process in a state of equilibrium is:
1. G = – 2.30RT log K
2. G = 2.30RT log K
3. Go = – 2.30RT log K
4. Go = 2.30RT log K

Subtopic:  Gibbs Energy Change |
 81%
Level 1: 80%+
NEET - 2015
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What is the value of \(\mathrm{K_{sp}}\) of \(\mathrm {Ag_2CO_3 (s) }\) in water at 25º C for the following reaction; 
\(\mathrm{Ag_2 CO_3 (s) \rightarrow 2Ag^+ (aq) + CO^{2-}_3 (aq)}\)

[Given: \(\text R = 8.314 \text J\text K^{–1} \text {mol}^{–1}\) \(\Delta \text G^\circ=+63.3~\text{kJ}\) ]

1. \(3.2 \times 10^{26}\)
2. \(8.0 \times 10^{-12}\)
3. \(2.9 \times 10^{-3}\)
4. \(7.9 \times 10^{-2}\)
Subtopic:  Gibbs Energy Change |
 61%
Level 2: 60%+
AIPMT - 2014
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Links

For the reaction:
\(\mathrm{X}_2 \mathrm{O}_4(l) \rightarrow 2 \mathrm{XO}_2(g)\)
with the given values \(\Delta U = 2.1 \, \text{kcal}\) and \(\Delta S = 20 \, \text{cal K}^{-1}\) at \(300 \, \text{K}\), what is the value of \(\Delta G\)?

1. +2.7 kcal
2. –2.7 kcal
3. +9.3 kcal
4. –9.3 kcal

Subtopic:  Gibbs Energy Change |
 78%
Level 2: 60%+
AIPMT - 2014
Hints

In which of the following reactions, the standard reaction entropy change
(S0) is positive, and standard Gibb's energy change
(G0) decreases sharply with increasing temperature?

1. C(graphite) + \(\frac{1}{2}\)O2(g) → CO(g)
2. CO(g) + \(\frac{1}{2}\)O2(g) → CO2(g)
3. Mg(s) + \(\frac{1}{2}\)O2(g) → MgO(s)
4. \(\frac{1}{2}\)C(graphite) + \(\frac{1}{2}\)O2(g) → \(\frac{1}{2}\)CO2(g)

Subtopic:  Gibbs Energy Change |
 71%
Level 2: 60%+
AIPMT - 2012
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The enthalpy of fusion of water is 1.435 kcal/mol. The molar entropy change for the melting of ice at 0 oC is:

1. 10.52 cal/(mol K)

2. 21.04 cal/(mol K)

3. 5.260 cal/(mol K)

4. 0.526 cal/(mol K)

Subtopic:  Thermochemistry |
 81%
Level 1: 80%+
AIPMT - 2012
Hints

The standard enthalpy of vaporization vapHo for water at 100 oC is 40.66 kJ mol–1. The internal energy of vaporization of water at 100 oC (in kJ mol–1) is: 
(Assume water vapour behaves like an ideal gas.)

1. +37.56

2. –43.76

3. +43.76

4. +40.66

Subtopic:  Enthalpy & Internal energy |
 61%
Level 2: 60%+
AIPMT - 2012
Hints

Identify which of the following is the correct option for free expansion of an ideal gas under adiabatic condition.
1. \(\Delta \mathrm{q} \neq 0, \Delta \mathrm{~T}=0, \mathrm{~W}=0 \)
2. \(\Delta \mathrm{q}=0, \Delta \mathrm{~T}=0, \mathrm{~W}=0 \)
3. \(\Delta \mathrm{q}=0, \Delta \mathrm{~T}<0, \mathrm{~W} \neq 0 \)
4. \(\Delta \mathrm{q}=0, \Delta \mathrm{~T} \neq 0, \mathrm{~W}=0\)
Subtopic:  2nd & 3rd Law of Thermodynamics | First Law of Thermodynamics |
 80%
Level 1: 80%+
AIPMT - 2011
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Given the following reaction:
\(4H(g)\)→  \(2 H_{2}\)\((g)\)
The enthalpy change for the reaction is -869.6 kJ. The dissociation energy of the H-H bond is:
1. -869.6 kJ
2. +434.8kJ
3. +217.4kJ
4. -434.8 kJ

Subtopic:  Enthalpy & Internal energy |
 68%
Level 2: 60%+
AIPMT - 2011
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