In an insulated container 1 mole of liquid, molar volume 100 ml is kept at 1 bar. Liquid is steeply taken to 100 bar, when volume of the liquid decreases by 1 ml. what are the values of Δ H & Δ U for the process?
= =
Volume of 1 mole liquid = 100 ml at pressure 1 bar
Volume of 1 mole liquid = 99 ml at pressure 100 bar
The process is an irreversible process as the process is changed so drastically from 1 bar to 100 bars.
w = −P(V2−V1) = −100(99−100) = 100 bar ml
from first law of thermodynamics we have Δ U = q + w
q = 0 as the container is insulated
∴ Δ U = 0 + 100 = 100 bar ml
Δ H = Δ U + PΔ V = Δ U + P2V2 − P1V1
Δ H = 100 + (100 × 99 − 1 × 100)
Δ H = 9900 bar ml