Thermodynamics · Question 13

Which amongst the following options is the correct relation between change in enthalpy and change in internal energy?

1. H = U + ng RT
2. H - U = - n RT
3. H + U = n R
4. H = U - ng RT

Which of the following p-V curve represents maximum work done?

1. [figure]
2. [figure]
3. [figure]
4. [figure]

One mole of an ideal gas at 300 K is expanded isothermally from 1 L to 10 L volume. U for this process is : (Use R = 8.314 J K-1 mol-1)

1. 0 J
2. 1260 J
3. 2520 J
4. 5040 J

Which one among the following is the correct option for right relationship between CP and CV for one mole of ideal gas?

1. CV = RCP
2. CP + CV = R
3. CP - CV = R
4. CP = RCV

For irreversible expansion of an ideal gas under isothermal condition, the correct option is :

1. U 0, Stotal = 0
2. U = 0, Stotal = 0
3. U 0, Stotal 0
4. U = 0, Stotal 0

For the reaction, 2Cl(g) Cl2(g), the correct option is :

1. r H > 0 and r S < 0
2. r H < 0 and r S > 0
3. r H < 0 and r S < 0
4. r H > 0 and r S > 0

The correct option for free expansion of an ideal gas under adiabatic condition is :

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

In which case change in entropy is negative?

1. Sublimation of solid to gas
2. 2H(g) H2(g)
3. Evaporation of water
4. Expansion of a gas at constant temperature

Under isothermal condition, a gas at 300 K expands from 0.1 L to 0.25 L against a constant external pressure of 2 bar. The work done by the gas is [Given that 1 L bar = 100 J]

1. 25 J
2. 30 J
3. −30 J
4. 5 kJ

The bond dissociation energies of X2, Y2 and XY are in the ratio of 1 : 0.5 : 1. H for the formation of XY is -200 kJ mol-1. The bond dissociation energy of X2 will be

1. 800 kJ mol-1
2. 200 kJ mol-1
3. 400 kJ mol-1
4. 100 kJ mol-1