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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NEET 2023 - Target Batch - Aryan Raj Singh
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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%
From NCERT
AIPMT - 2011
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Standard entropies of X2, Y2 and XY3 are 60, 40 and 50JK-1mol-1 respectively. For the reaction 
12X2 + 32Y2   XY3 ; H = -30 kJ to be at equilibrium, the temperature should be:

1. 750 K

2. 1000 K

3. 1250 K

4. 500 K

Subtopic:  Gibbs Energy Change |
 78%
From NCERT
AIPMT - 2010
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From 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 reaction, 

will be:

1. 1523.6 kJ mol-1 2. -243.6 kJ mol-1
3. -120.0 kJ mol-1 4. 553.0 kJ mol-1
Subtopic:  Thermochemistry |
 75%
From NCERT
AIPMT - 2009
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The values of ΔH and ΔS for the given reaction are 170 kJ and 170 JK-1, respectively.
C(graphite) + CO2(g)→2CO(g) 
This reaction will be spontaneous at:

1. 710 K
2. 910 K
3. 1110 K
4. 510 K

Subtopic:  Gibbs Energy Change |
 88%
From NCERT
AIPMT - 2009
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For the gas phase reaction, 
 PCl5(g)PCl3(g)+Cl2(g)
which of the following conditions is correct?

1. ΔH = 0 and ΔS < 0

2. ΔH > 0 and ΔS > 0

3. ΔH < 0 and ΔS < 0

4. ΔH > 0 and ΔS < 0

Subtopic:  Gibbs Energy Change |
 81%
From NCERT
AIPMT - 2008
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The standard free energies of formation(in kJ/mol) at 298 K are -237.2, -394.4, and -8.2 for H2O(l), CO2(g), and pentane (g), respectively. The value of Ecell for the pentane-oxygen fuel cell is:

1. 1.968 V
2. 2.0968 V
3. 1.0968 V
4. 0.0968 V

Subtopic:  Gibbs Energy Change |
 54%
From NCERT
AIPMT - 2008
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Bond dissociation enthalpy of H2, Cl2, and HCl are 434, 242, and 431 kJ mol1 respectively. Enthalpy of formation of HCl is:

1. 93 kJ mol-1
2. - 245 kJ mol-1
3. -93 kJ mol-1
4. 245 kJ mol-1

Subtopic:  Thermochemistry |
 64%
From NCERT
AIPMT - 2008
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The bond energy of H—H and Cl-Cl is 430 kJ mol-1 and 240 kJ mol-1 respectively
and ΔHf for HCl is -90 kJ mol-1. The bond enthalpy of HCl is:

1. 290 kJ mol-1

2. 380 kJ mol-1

3. 425 kJ mol-1

4. 245 kJ mol-1

Subtopic:  Thermochemistry |
 60%
From NCERT
AIPMT - 2007
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NEET 2023 - Target Batch - Aryan Raj Singh
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Which of the following statements about the advantage of roasting sulphide ore before reduction is not true?
 
1. Carbon and hydrogen act as suitable reducing agents for metal sulphides
2. The \(\Delta_f G^0\) of the sulphide is greater than those for \(C S_2\) and \(\mathrm{H}_2 \mathrm{~S}\)
3. The \(\Delta_f G^0\) is negative for roasting of sulphur ore to oxide.
4. Roasting of the sulphide to the oxide is thermodynamically feasible
Subtopic:  Gibbs Energy Change | Hess's Law |
From NCERT
AIPMT - 2007
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NEET 2023 - Target Batch - Aryan Raj Singh
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