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
Entropy decreases during:
1. Crystallization of sucrose from solution
2. Rusting of iron
3. Melting of ice
4. Vaporization of camphor
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 |
(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. \(\mathrm{C}(\text { graphite })+\frac{1}{2} \mathrm{O}_{2(\mathrm{~g})}+2 \mathrm{H}_{2(\mathrm{~g})} \rightarrow \mathrm{CH}_3 \mathrm{OH}_{(\mathrm{l})}\)
The difference in for combustion of benzoic acid at 300 K is equal to-
1. -1.247 kJ
2. +1.247 kJ
3. -1.247 J
4. +1.247 J
When 4 g of iron is burnt to ferric oxide at a constant pressure, 29.28 kJ of heat is evolved.
The enthalpy of formation of ferric oxide will be-
(At. mass of Fe = 56) ?
1. 81.98 kJ
2. 819.8 kJ
3. 40.99 kJ
4. +819.8 kJ
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 maximum work done in expanding 16g isothermally at 300 K and occupying a volume of
5 dm3 until the volume becomes 25 dm3 is:
1. –2.01 J
2. 2.01× J
3. +2.81 J
4. +2.01J