The internal energy of a substance

• decrease with increase in temperature

• increase with increase in temperature

• remains unaffected with change in temperature

• calculated by E = mc²

In an isothermal process

• $∆\mathrm{H} = ∆\mathrm{E}\hspace{0.17em}+\hspace{0.17em}\mathrm{P}∆\mathrm{V}$

• $∆\mathrm{H} = \mathrm{W}$

• $∆\mathrm{H} = ∆\mathrm{E}$

• $∆\mathrm{H} =\mathrm{S}∆\mathrm{T}$

53.

In an isochoric process, the increase in internal energy is equal to:

• the sum of heat absorbed and work done

• the work done

• heat absorbed

• heat evolved

Heat of a reaction at constant pressure is equal to:

• H_P - H_R

• H_P + H_R

• H_P $\times$ H_R

• $\frac{{\mathrm{H}}_{\mathrm{P}}}{{\mathrm{H}}_{\mathrm{R}}}$

10 moles of ideal gas expand isothermally and reversibly from a pressure of 10 atrn to 1 atm at 300K. What is the largest mass which can lifted through a height of 100 meter?

• 48.75 kg

• 58.55 kg

• 75.64 kg

• 64.13 kg

The cooling in refrigerator is due to :

• the reaction of the refrigerator gas

• the expansion of ice

• the expansion of the gas in the refrigerator

• the work of the compressor

The temperature of the system decreases in an :

• adiabatic compression

• isothermal compression

• isothermal expansion

• adiabatic expansion

A certain reaction is at equilibrium at 82°C and the enthalpy change for this reaction is 21.3 kJ. The value of $∆$S(JK^-1mol^-1) for the reaction is :

• 55.0

• 60.0

• 68.5

• 120.0

The heat is liberated when 1.89 g of benzoic acid is burnt in a bomb calorimeter at 25 °C and it increases the temperature of 18.94 kg of water by 0.632 °C. If the specific heat of water at 25 °C is 0.998 cal/g-deg, then value of the heat of combustion of benzoic acid is

• 881.1 kcal

• 981.1 kcal

• 771.1 kcal

• 871.2 kcal

Assertion : Spontaneous process is an irreversible process and may be reversed by some external agency.

Reason : Decrease in enthalpy is a contributory factor for spontaneity.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false

• If both assertion and reason are false.