Isothermal process (redirected from Isothermal expansion)

Isothermal process

A thermodynamic process which occurs with a heat addition or removal rate just adequate to maintain constant temperature. The change in the internal energy per mole U accompanying a change in volume in an isothermal process is given by the equation below, where T is the

temperature, P is the pressure, and V is the volume per mole. The integral in the equation is zero for an ideal gas, and approximately zero for a condensed phase (solid or liquid) for which the volume changes vary little with pressure. Thus, in both these cases, U₂ = U₁. For real gases, the integral is nonzero, and the internal energy change is computed using the equation of state of the gas in the equation. See Thermodynamic processes