State, Equation Of

Any of a class of equations that relate the pressure &math.P;, volume &math.V;, and temperature &math.T; of a given substance in thermodynamic equilibrium.

For example, the equation &math.P;&math.V; = &math.n;&math.R;&math.T;, where &math.n; is the number of moles of gas and &math.R; is the universal gas constant, relates the pressure, volume, and temperature of a perfect gas. Real gases, solids, and liquids have more complicated equations of state. &Seealso; thermodynamics.