Thermodynamics · Question 61

Considering entropy (S) as a thermodynamic parameter, the criterion for the spontaneity of any process is

1. Ssystem + Ssurroundings > 0
2. Ssystem - Ssurroundings > 0
3. Ssystem > 0 only
4. Ssurroundings > 0 only

The work done during the expansion of a gas from a volume of 4 dm3 to 6 dm3 against a constant external pressure of 3 atm is (1 L atm = 101.32 J)

1. -6 J
2. -608 J
3. +304 J
4. -304 J

For the reaction, C3H8(g) + 5O2(g) 3CO2(g) + 4H2O(l) at constant temperature, H - E is

1. +RT
2. -3RT
3. +3RT
4. -RT

The densities of graphite and diamond at 298 K are 2.25 and 3.31 g cm-3, respectively. If the standard free energy difference ( G ) is equal to 1895 J mol-1, the pressure at which graphite will be transformed into diamond at 298 K is

1. 11.14 108 Pa
2. 11.14 107 Pa
3. 11.14 106 Pa
4. 11.14 105 Pa

What is the entropy change (in J K-1 mol-1) when one mole of ice is converted into water at 0 C? (The enthalpy change for the conversion of ice to liquid water is 6.0 kJ mol-1 at 0 C).

1. 20.13
2. 2.013
3. 2.198
4. 21.98

For which one of the following equations is H react equal to H f for the product ?

1. Xe(g) + 2F2(g) XeF4(g)
2. 2CO(g) + O2(g) 2CO2(g)
3. N2(g) + O3(g) N2O3(g)
4. CH4(g) + 2Cl2(g) CH2Cl2(l) + 2HCl(g)

The molar heat capacity of water at constant pressure, C, is 75 J K-1 mol-1. When 1.0 kJ of heat is supplied to 100 g of water which is free to expand, the increase in temperature of water is

1. 1.2 K
2. 2.4 K
3. 4.8 K
4. 6.6 K

Unit of entropy is

1. J K-1 mol-1
2. J mol-1
3. J-1 K-1 mol-1
4. J K mol-1

In a closed insulated container a liquid is stirred with a paddle to increase the temperature. Which of the following is true?

1. E = W 0, q = 0
2. E = W = q 0
3. E = 0, W = q 0
4. W = 0, E = q 0

Heat of combustion Ho for C(s), H2(g) and CH4(g) are -94, -68 and -213 kcal/mol, then Ho for C(s) + 2H2(g) CH4(g) is

1. -17 kcal
2. -111 kcal
3. -170 kcal
4. -85 kcal