# How does enthalpy change with pressure?

Mar 13, 2014

Enthalpy does not change with pressure if everything else remains constant.

$H = U + P V$

For an ideal gas,

ΔH = ΔU + Δ(PV) = ΔU + Δ(nRT) = ΔU + nRΔT

U depends only on the temperature.

If temperature remains constant, ΔU = 0 and ΔT= 0.

ΔH = 0 + 0 = 0.

Enthalpy does not change with pressure.