Identify the correct statement regarding entropy:
1. | At absolute zero of temperature, the entropy of all crystalline substances is taken to be zero |
2. | At absolute zero of temperature, the entropy of a perfectly crystalline substance is +ve |
3. | At absolute zero of temperature, the entropy of a perfectly crystalline substance is taken to be zero |
4. | At 0 °C , the entropy of a perfectly crystalline substance is taken to be zero |
One mole of an ideal gas at 300 K is expanded isothermally from an initial volume of 1 litre to 10 litres. The ∆E for this process is:
(R = 2 cal. )
1. 1381.1 cal.
2. Zero
3. 163.7 cal.
4. 9 lit. atm
Which of the following statements are true for a cyclic process?
a. | W = 0 |
b. | ∆E = 0 |
c. | ∆H = 0 |
d. | ∆E ≠ 0 |
1. a, b
2. b, c
3. c, d
4. a, d
If a system is expanded under adiabatic process, then:
1. Temperature increases
2. ∆E decreases
3. ∆E increases
4. None of the above
Which of the following is true for a reaction in which all the reactants & products are liquids:
1. ∆H = ∆E
2. ∆H = ∆W
3. ∆H > ∆E
4. None of the above
for the following reaction is:
1. | -731 J | 2. | -1317 J |
3. | -501 J | 4. | +731 J |
At 27ºC latent heat of fusion of a compound is 2930 J/mol. Entropy change is:
1. 9.77 J/mol K
2. 10.77 J/mol K
3. 9.07 J/mol K
4. 0.977 J/mol K
For the reaction
C2H5OH(l) + 3O2(g) →2CO2(g) + 3H2O(l) which one is true:
1. | ∆H = ∆E – RT | 2. | ∆H = ∆E + RT |
3. | ∆H = ∆E + 2RT | 4. | ∆H = ∆E – 2RT |
For the given reaction
, the heat of formations of are -188 kJ/mol & -286 KJ/mol respectively. The change in the enthalpy of the reaction will be:
1. – 196 kJ/mol
2. + 196 kJ/mol
3. + 948 kJ/mol
4. – 948 kJ/mol
When 1 mol gas is heated at constant volume, the temperature is raised from 298 to 308 K. Heat supplied to the gas is 500 J. The correct statement among the following is:
1. q = w = 500 J, ∆U = 0
2. q = ∆U = 500 J, w = 0
3. q = w = 500 J, ∆U = 0
4. ∆U = 0, q = w = – 500 J