The enthalpy of combustion of carbon to CO2 is –393.5 kJ mol-1. The amount of heat released upon formation of 35.2 g of CO2 from carbon and dioxygen gas would be:
1. | –393.5 kJ mol–1 | 2. | –314.8 kJ mol–1 |
3. | +314.8 kJ mol–1 | 4. | –320.5 kJ mol–1 |
For the reaction, , the value of ∆H and ∆S are respectively:
1.
2.
3.
4.
For the reaction A + B → C + D + q (kJ/mol), entropy change is positive. The reaction will be
1. Possible only at high temperature
2. Possible only at low temperature
3. Not possible at any temperature
4. Possible at any temperature
The enthalpy of combustion of methane, graphite, and dihydrogen at 298 K are, –890.3 kJ mol–1 , –393.5 kJ mol–1, and –285.8 kJ mol–1 respectively. The enthalpy of formation of CH4(g) is-
1. | –74.8 kJ mol–1 | 2. | –52.27 kJ mol–1 |
3. | +74.8 kJ mol–1 | 4. | +52.26 kJ mol–1 |
Match the following process with entropy change:
Reaction | Entropy change | ||
A. | A liquid vaporizes | 1. | |
B. | Reaction is non-spontaneous at all temperatures and is positive | 2. | |
C. | Reversible expansion of an ideal gas | 3. |
Codes:
A | B | C | |
1. | 2 | 3 | 1 |
2. | 1 | 2 | 3 |
3. | 1 | 3 | 2 |
4. | 3 | 2 | 1 |
Match the following parameters with a description for spontaneity.
\(\Delta\) (Parameters) \(\Delta r\ H^⊝\) \(\Delta r\ S^⊝\)\(\Delta r\ G^⊝\) | 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 |
Assertion (A): | Combustion of all organic compounds is an exothermic reaction. |
Reason (R): | The enthalpies of all elements in their standard state are zero. |
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. |
Assertion (A): | Spontaneous process is an irreversible process and may be reversed by some external agency. |
Reason (R): | A decrease in enthalpy is a contributing factor to spontaneity. |
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. |
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. |
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. |