Isochoric Process
A process carried out at constant volume, so that no expansion work is done.
Formula / equation
w = 0, q_V = ΔU
Unit
J
In depth
An isochoric process takes place in a rigid sealed container. Because the volume cannot change, no pressure–volume work is possible and all heat exchanged appears as a change in internal energy, which is why bomb calorimetry measures ΔU rather than ΔH.
Examples in the real world
Combustion inside a sealed steel bomb; heating a gas in a rigid cylinder so its pressure rises.