Thermodynamics · Question 38

Enthalpy change for the reaction, 4H(g) 2H2(g) is -869.6 kJ The dissociation energy of H-H bond is

1. -434.8 kJ
2. -869.6 kJ
3. +434.8 kJ
4. +217.4 kJ

Which of the following is correct option for free expansion of an ideal gas under adiabatic condition ?

1. q = 0, T 0, w = 0
2. q 0, T = 0, w = 0
3. q = 0, T = 0, w = 0
4. q = 0, T < 0, w 0

Match List I (Equations) with List II (Type of processes) and select the correct option.

1. A - (i), B - (ii), C - (iii), D - (iv)
2. A - (iii), B - (iv), C - (ii), D - (i)
3. A - (iv), B - (i), C - (ii), D - (iii)
4. A - (ii), B - (i), C - (iv), D - (iii)

Three moles of an ideal gas expanded spontaneously into vacuum. The work done will be

1. infinite
2. 3 Joules
3. 9 Joules
4. zero

For vaporization of water at 1 atmospheric pressure, the values of H and S are 40.63 kJ mol-1 and 108.8 J K-1 mol-1, respectively. The temperature when Gibbs energy change ( G) for this transformation will be zero, is

1. 273.4 K
2. 393.4 K
3. 373.4 K
4. 293.4 K

The following two reactions are known Fe2O3(s) + 3CO(g) 2Fe(s) + 3CO2(g); H = -26.8 kJ FeO(s) + CO(g) Fe(s) + CO2(g); H = -16.5 kJ The value of H for the following reaction Fe2O3(s) + CO(g) 2FeO(s) + CO2(g) is

1. +10.3 kJ
2. -43.3 kJ
3. -10.3 kJ
4. +6.2 kJ

Standard entropies of X2, Y2 and XY3 are 60, 40 and 50 J K-1 mol-1 respectively. For the reaction 12X2 + 32Y2 XY3, H = -30 kJ, to be at equilibrium, the temperature should be

1. 750 K
2. 1000 K
3. 1250 K
4. 500 K

The values of and for the reaction, C(graphite) + CO2(g) 2CO(g) are 170 kJ and 170 J K-1, respectively. This reaction will be spontaneous at

1. 910 K
2. 1110 K
3. 510 K
4. 710 K

From the following bond energies : H – H bond energy : 431.37 kJ mol-1 C = C bond energy : 606.10 kJ mol-1 C – C bond energy : 336.49 kJ mol-1 C – H bond energy : 410.50 kJ mol-1 Enthalpy for the reaction, [figure] will be

1. -243.6 kJ mol-1
2. -120.0 kJ mol-1
3. 553.0 kJ mol-1
4. 1523.6 kJ mol-1

Bond dissociation enthalpies of H2, Cl2 and HCl are 434, 242 and 431 kJ mol-1 respectively. Enthalpy of formation of HCl is

1. -93 kJ mol-1
2. 245 kJ mol-1
3. 93 kJ mol-1
4. -245 kJ mol-1