Question

If the work is done on an adiabatic wall, then which of the following is true?

(a) ΔU = -W

(b) ΔU = W

(c) ΔU + W = 0

(d) ΔU = -W

This question was posed to me by my school teacher while I was bunking the class.

I want to ask this question from Thermodynamic Terms topic in chapter Thermodynamics of Chemistry – Class 11

Answer 1

The correct option is (b) ΔU = W

To explain: In an adiabatic process, the total energy is always zero. We have that ΔH = ΔU + W, as ΔH is zero, we get ΔU + W = 0; ΔU = -W. But as work is done on the system by observing no heat W becomes negative, so ΔU = -(-)W = W. Hence ΔU = W.