Question

Adiabatic expansion of ideal gas into vacuum correspond to (i) w=0 (ii) delta E =0 (iii) delta H=0 (iv) All of these
EXPLAIN WITH PROPER REASONS

Answer 1

iv) All of these

Explanation:

At vacuum, P=0.

Hence, w= -P∆V = 0.

In an adiabatic process, there will be no flow of heat. Hence, q= 0.

Change in internal energy, ∆E = q + w

(from I law of thermodynamics)

∆E= 0 + 0

∆E= 0.

Change in enthalpy, ∆H= ∆E + P∆V

= 0 + 0

( P=0 at vacuum)

Hence, ∆H= 0.

Answer 2

The answer is all of these. option(iv)

• Since the adiabatic expansion is taking place in a vacuum, the temperature here will be constant.
• When the temperature is constant, the change in volume of the ideal gas will also be constant which is zero.
• Therefore other parameters like ΔE, ΔH will be zero which leads to work done to be zero.
• Therefore option (iv) is the correct answer.