The correct statement among the following is-

1. The presence of reacting species in a covered beaker is an example of an open system.
2. There is an exchange of energy as well as matter between the system and the surroundings in a closed system.
3. The presence of reactants in a closed vessel made up of copper is an example of a closed system.
4. The presence of reactants in a thermos flask or any other closed insulated vessel is an example of a closed system.

.

Subtopic:  Thermodynamics' Properties and process |
 69%
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If the volume of a gas is reduced to half from its original volume, then the specific heat will-

1. Reduce to half 2. Be Doubled
3. Remain constant 4. Increase four times
Subtopic:  Classification of System, Extensive & Intensive Properties |
 80%
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The enthalpy of formation of all elements in their standard state is-

1. Unity 2. Zero
3. Less than zero 4. Different for each element
Subtopic:  Thermodynamics' Properties and process |
 79%
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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 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 |
 66%
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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 mol-1 respectively.

The value of rH for the reaction would be-

N2O4g+3COgN2Og+3CO2g

1. -777.7 kJ mol-1
2.  +777.7 kJ mol-1
3.  +824.9 kJ mol-1
4. - 345.4 kJ mol-1

Subtopic:  Thermochemistry |
 75%
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 N2 + 3 H2  2NH3 ; rH° = -92.4 kJ mol-1. The standard enthalpy of formation of NH3 gas in the above reaction would be-

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 |
 81%
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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 |
 61%
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The equilibrium constant for a reaction is 10. The value of G° will be:

(R = 8.314 J K-1 mol-1 ; T = 300 K)

1. -5.74 kJ mol-1
2. - 5.74 J mol-1
3. + 4.57 kJ mol-1
4. -57.4 kJ mol-1

Subtopic:  Gibbs Energy Change |
 73%
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Thermodynamics is not concerned about-

1. Energy changes involved in a chemical reaction

2. The extent to which a chemical reaction proceeds

3. The rate at which a reaction proceeds

4. The feasibility of a chemical reaction

Subtopic:  Thermodynamics' Properties and process |
 71%
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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 |
 82%
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