The unit of entropy is -

1. J mol–1

2. JK mol–1

3. J mol–1 K–1

4. J–1 K–1 mol–1

Subtopic:  Spontaneity & Entropy |
 85%
Level 1: 80%+
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The enthalpy and entropy change for the reaction :

Br2 (l) + Cl2 (g) 2BrCl (g)

are 30 kJ mol-1 and 105 J K-1 mol-1 respectively.

The temperature at which the reaction will be in equilibrium is :

1. 285.7 K 2. 273.4 K
3. 450.9 K 4. 300.1 K
Subtopic:  Spontaneity & Entropy |
 82%
Level 1: 80%+
NEET - 2006
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Which of the following is not correct?

1. G is zero for a reversible reaction.

2. G is positive for a spontaneous reaction.

3. G is negative for a spontaneous reaction.

4. G is positive for a non-spontaneous reaction.

Subtopic:  Spontaneity & Entropy |
 85%
Level 1: 80%+
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Select the correct option based on statements below:
Assertion (A):  A liquid crystallizes into a solid and is accompanied by a decrease in entropy.
Reason (R):  In crystals, molecules organize in an ordered manner.
 
1.  Both (A) and (R) are True and (R) is the correct explanation of (A).
2. Both (A) and (R) are True but (R) is not the correct explanation of (A).
3. (A) is True but (R) is False.
4. (A) is False but (R) is True.
Subtopic:  Spontaneity & Entropy |
 85%
Level 1: 80%+
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Entropy decreases during:

1. Crystallization of sucrose from solution

2. Rusting of iron

3. Melting of ice

4. Vaporization of camphor

Subtopic:  Spontaneity & Entropy |
 84%
Level 1: 80%+
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The entropy change in the fusion of one mole of a solid melting at 27°C  is:       

(the latent heat of fusion is 2930 J mol-1)                                                                                   

1. 9.77 JK-1mol-1               

2. 19.73 JK-1mol-1               

3. 2930 JK-1mol-1               

4. 108.5 JK-1mol-1          

Subtopic:  Spontaneity & Entropy |
 81%
Level 1: 80%+
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At a temperature of 300K, what is the entropy change for the reaction given below?

2H2 (g) + O2 (g) 2H2O(l)

Standard entropies of H2 (g), O2(g) and H2O(l) are 126.6, 201.20 and 68.0 JK-1mol-1 respectively.

1. -318.4 JK-1mol-1                           

2. 318.4 JK-1mol-1 

3. 31.84 JK-1mol-1                             

4. None of the above

Subtopic:  Spontaneity & Entropy |
 81%
Level 1: 80%+
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Match the following process with entropy change:

Reaction Entropy change
A. A liquid vaporizes 1.  S=0
B. Reaction is non-spontaneous at all temperatures and H is positive 2.  S=positive
C. Reversible expansion of an ideal gas 3.  S=negative

Codes:

A B C
1. 2 3 1
2. 1 2 3
3. 1 3 2
4. 3 2 1
Subtopic:  Spontaneity & Entropy |
 81%
Level 1: 80%+
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Given the reaction:
\(2 \mathrm{Cl}(\mathrm{~g}) \rightarrow \mathrm{Cl}_2(\mathrm{~g})\)
What are the values of \(∆\mathrm{H}\) and \(∆\mathrm{S}\), respectively?

1. \(\Delta \mathrm{H}=0, \Delta \mathrm{~S}=-\mathrm{ve}\)
2. \(\Delta \mathrm{H}=0, \Delta \mathrm{~S}=0\)
3. \(\Delta \mathrm{H}=-\mathrm{ve}, \Delta \mathrm{~S}=-\mathrm{ve}\)
4. \(\Delta \mathrm{H}=+\mathrm{ve}, \Delta \mathrm{~S}=+\mathrm{ve}\)

Subtopic:  Spontaneity & Entropy |
 79%
Level 2: 60%+
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Match the following parameters with a description for spontaneity.

\(\Delta r\ H^⊝\) \(\Delta r\ S^⊝\) \(\Delta r\ G^⊝\) Description
A.  + + 1.  Non-spontaneous at high temperature
B.  + at high T 2.  Spontaneous at all temperatures
C.  + 3.  Non-spontaneous at all temperatures

Codes:

A B C
1. 3 1 2
2. 1 2 3
3. 1 3 2
4. 3 2 1
Subtopic:  Spontaneity & Entropy |
 79%
Level 2: 60%+
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