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
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
Change in entropy is negative for:
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
(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. \(\mathrm{C}(\text { graphite })+\frac{1}{2} \mathrm{O}_{2(\mathrm{~g})}+2 \mathrm{H}_{2(\mathrm{~g})} \rightarrow \mathrm{CH}_3 \mathrm{OH}_{(\mathrm{l})}\)
An ideal gas expands isothermally from at 300 K against a constant pressure of . The work done by the gas is:
1. | +270 kJ | 2. | –900 J |
3. | +900 kJ | 4. | –900 kJ |
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.
2.
3.
4.
The for vaporization of a liquid is \(20 \mathrm{~kJ} / \mathrm{mol}.\) Assuming ideal behaviour, the change in internal energy for the vaporization of \(1 \mathrm{~mol}\) of the liquid at \(60^{\circ} \mathrm{C}\) and 1 bar is close to:
1. | \(13.2 \mathrm{~kJ} / \mathrm{mol} \) | 2. | \(17.2 \mathrm{~kJ} / \mathrm{mol} \) |
3. | \(19.5 \mathrm{~kJ} / \mathrm{mol} \) | 4. | \(20.0 \mathrm{~kJ} / \mathrm{mol}\) |
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