Question

Sub: Thermodynamics-Chemical Engineering

In reversible expansion process initial or final internal energy is higher?

Explain Why?

Answer 1

From the first law of thermodynamics

dQ = ΔU + dW ........... Eq1

Where dQ = net heat transfer

ΔU = change in internal energy

dW = net work done

For adiabatic process, there is no heat exchange

Q=0

For expansion process

dW > 0

From eq1

0 = ΔU + dW

∆U < 0

U2 - U1 < 0

U1 > U2

Initial internal energy is higher.