Q. No.A gas is allowed to expand in a well-insulated container against a constant external pressure of 2.5atm from an initial volume of 2.50 L to a final volume of 4.50L. The change in internal energy U of the gas in joules will be:
1.
–500J
2.
–505J
3.
–506J
4.
–508J
1. H > 0 and S< 0
2. H < 0 and S> 0
3. H < 0 and S< 0
4. H > 0 and S = 0
The heat of combustion of carbon to CO2 is –393.5 KJ/mol. The heat released upon the formation of 35.2 g of CO2 from carbon and oxygen gas is:
1. –315 KJ
2. +315 KJ
3. –630 KJ
4. +630 KJ
The correct statement for a reversible process in a state of equilibrium is:
1. G = – 2.30RT log K
2. G = 2.30RT log K
3. Go = – 2.30RT log K
4. Go = 2.30RT log K
\(\mathrm{Ag_2 CO_3 (s) \rightarrow 2Ag^+ (aq) + CO^{2-}_3 (aq)}\)
[Given: \(\text R = 8.314 \text J\text K^{–1} \text {mol}^{–1}\) ; \(\Delta \text G^\circ=+63.3~\text{kJ}\) ]
1. \(3.2 \times 10^{26}\)
2. \(8.0 \times 10^{-12}\)
3. \(2.9 \times 10^{-3}\)
4. \(7.9 \times 10^{-2}\)
For the reaction:
\(\mathrm{X}_2 \mathrm{O}_4(l) \rightarrow 2 \mathrm{XO}_2(g)\)
with the given values \(\Delta U = 2.1 \, \text{kcal}\) and \(\Delta S = 20 \, \text{cal K}^{-1}\) at \(300 \, \text{K}\), what is the value of \(\Delta G\)?
1. +2.7 kcal
2. –2.7 kcal
3. +9.3 kcal
4. –9.3 kcal
In which of the following reactions, the standard reaction entropy change
is positive, and standard Gibb's energy change
decreases sharply with increasing temperature?
| 1. | C(graphite) + \(\frac{1}{2}\)O2(g) → CO(g) |
| 2. | CO(g) + \(\frac{1}{2}\)O2(g) → CO2(g) |
| 3. | Mg(s) + \(\frac{1}{2}\)O2(g) → MgO(s) |
| 4. | \(\frac{1}{2}\)C(graphite) + \(\frac{1}{2}\)O2(g) → \(\frac{1}{2}\)CO2(g) |
The enthalpy of fusion of water is 1.435 kcal/mol. The molar entropy change for the melting of ice at 0 oC is:
1. 10.52 cal/(mol K)
2. 21.04 cal/(mol K)
3. 5.260 cal/(mol K)
4. 0.526 cal/(mol K)
The standard enthalpy of vaporization for water at 100 oC is 40.66 kJ mol–1. The internal energy of vaporization of water at 100 oC (in kJ mol–1) is:
(Assume water vapour behaves like an ideal gas.)
1. +37.56
2. –43.76
3. +43.76
4. +40.66
1. \(\Delta \mathrm{q} \neq 0, \Delta \mathrm{~T}=0, \mathrm{~W}=0 \)
2. \(\Delta \mathrm{q}=0, \Delta \mathrm{~T}=0, \mathrm{~W}=0 \)
3. \(\Delta \mathrm{q}=0, \Delta \mathrm{~T}<0, \mathrm{~W} \neq 0 \)
4. \(\Delta \mathrm{q}=0, \Delta \mathrm{~T} \neq 0, \mathrm{~W}=0\)
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