The heat of combustion of carbon to CO2 is -393.5 KJ/mol. The heat changed 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 |
 73%
From NCERT
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 |
 78%
From NCERT
NEET - 2015
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Given the Gibbs free energy change, \(\Delta G^\circ=+63.3~kJ,\) for the following reaction, 
\(Ag_2 CO_3 (g) \rightarrow 2Ag^+ (aq) + CO^{2-}_3 (aq)\)
\(K_{sp}\) of \(Ag_2CO_3 (s) \) in water at 25º C is (R = 8.314 JK-1 mol-1)

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 |
 60%
From NCERT
AIPMT - 2014
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Which of the following statements is correct for the spontaneous adsorption of a gas?

1. ∆ S is negative and therefore,  ∆ H should be highly positive
2. ∆ S is negative and therefore,  ∆ H should be highly negative
3. ∆ S is positive and therefore,  ∆ H should be negative
4. -∆ S is positive and therefore,  ∆ H should also be highly positive

Subtopic:  Spontaneity & Entropy |
 57%
From NCERT
AIPMT - 2014
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Given the reaction: 
X2O4(l) → 2XO2(g) 
ΔU = 2.1 kcal, ΔS = 20 cal K–1 at 300 K 
The value of ΔG is:
1. 2.7 kcal
2. -2.7 kcal
3. 9.3 kcal
4. -9.3 kcal

Subtopic:  Gibbs Energy Change |
 78%
From NCERT
AIPMT - 2014
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When 5 litres of a gas mixture of methane and propane is perfectly combusted at 0°C and 1 atmosphere, 16 litres of oxygen at the same temperature and pressure is consumed. The amount of heat released from this combustion in kJ (\(\Delta \)Hcomb. (CH4) = 890 kJ mol–1, \(\Delta \)Hcomb( C3H8) = 2220 kJ mol–1) is:
1. 38
2. 317
3. 477
4. 32
Subtopic:  Thermochemistry |
 60%
From NCERT
NEET - 2013
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Three thermochemical equations are given below:
(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 |
 81%
From NCERT
NEET - 2013
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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 |
 69%
From NCERT
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 |
 79%
From NCERT
AIPMT - 2012
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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 |
 59%
From NCERT
AIPMT - 2012
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