How much work does a gas do when expanding by 0.5 m³ at 400 kPa?

Question

A gas expands by 0.5 m³ at a constant pressure of 400 kPa. How much work does it do? Give the answer in kJ.

Explanation

At constant pressure, the work done by a gas is W = pΔV.

Substituting the values gives W = 400 kPa × 0.5 m³ = 200 kJ, because 1 kPa·m³ = 1 kJ.

The gas is expanding, so the work done by the gas is positive.