As an isolated box, equally partitioned, contains two ideal gasses A and B as shown:

When the partition is removed, the gases mix. The changes in enthalpy and entropy in the process, respectively, are
1. Zero, positive
2. Zero, negative
3. Positive, zero
4. Negative, zero
The entropy change in the isothermal reversible expansion of 2 moles of an ideal gas from 10 to 100 L at 300 K is:
1. \(42.3 \mathrm{~J} \mathrm{~K}^{-1}\)
2. \(35.8 \mathrm{~J} \mathrm{~K}^{-1}\)
3. \(38.3 \mathrm{~J} \mathrm{~K}^{-1}\)
4. \(32.3 \mathrm{~J} \mathrm{~K}^{-1}\)
(298K) of methanol is given by the chemical equation:
1. \(\mathrm{C}(\text { diamond })+\frac{1}{2} \mathrm{O}_{2(\mathrm{~g})}+2 \mathrm{H}_{2(\mathrm{~g})} \rightarrow \mathrm{CH}_3 \mathrm{OH}_{(\mathrm{l})}\)
2. \(\mathrm{CH}_{4(\mathrm{~g})}+\frac{1}{2} \mathrm{O}_{2(\mathrm{~g})} \rightarrow \mathrm{CH}_3 \mathrm{OH}_{(\mathrm{g})}\)
3. \(\mathrm{CO}_{(\mathrm{g})}+2 \mathrm{H}_{2(\mathrm{~g})} \rightarrow \mathrm{CH}_3 \mathrm{OH}_{(\mathrm{l})}\)
4. \(\mathrm{C}(\text { graphite })+\frac{1}{2} \mathrm{O}_{2(\mathrm{~g})}+2 \mathrm{H}_{2(\mathrm{~g})} \rightarrow \mathrm{CH}_3 \mathrm{OH}_{(\mathrm{l})}\)
A piston filled with 0.04 mol of an ideal gas expands reversibly from 50.0 mL to 375 mL at a constant temperature of 37.0ºC. As it does so, it absorbs 208 J of heat. The values of q and w for the process will be-
(R = 8.314 J/mol K) (ln 7.5 = 2.01)
| 1. | q = +208 J, w = -208 J | 2. | q = -208 J, w = -208 J |
| 3. | q = -208 J, w = + 208 J | 4. | q = +208 J, w = + 208 J |
Entropy decreases during:
1. Crystallization of sucrose from solution
2. Rusting of iron
3. Melting of ice
4. Vaporization of camphor
Find the process showing negative entropy change:
1. Bromine (l)Bromine(g)
2. C(s) + H2O(g) CO(g) + H2(g)
3. N2(g,10 atm)N2(g,1 atm)
4. Fe ( 1mol, 400 K) Fe( 1mol, 300 K)
For the following given equations and values, determine the enthalpy of reaction at 298 K for the reaction:
C2H4(g) + 6F2(g) 2CF4(g) + 4HF(g)
H2(g) + F2(g) 2HF(g) = -537 kJ
C(s) + 2F2(g) CF4(g) =-680 kJ
2C(s) + 2H2(g) C2H4(g) = 52 kJ
1. –1165 kJ
2. –2486 kJ
3. +1165 kJ
4. +2486 kJ
When 4 g of iron is burnt in oxygen to form ferric oxide at constant pressure, 29.28 kJ of heat is evolved. Calculate the enthalpy of formation of ferric oxide.
(At. mass of Fe = 56) ?
1. 81.98 kJ
2. 819.8 kJ
3. 40.99 kJ
4. +819.8 kJ
The standard Gibbs free energies of formation of H₂O(l), CO₂(g), and C₅H₁₂(g) at 298 K are
−237.2, −394.4 and −8.2 kJ mol⁻¹, respectively.
Calculate the standard cell potential (E°cell) of a pentane–oxygen fuel cell at 298 K.
(Given: Faraday constant, F = 96500 C mol⁻¹)
1. 1.968 V
2. 2.0968 V
3. 1.0968 V
4. 0.0968 V
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