PVT-surface

for: a given amount (usually expressed in moles) of any substance whose equilibrium states are determined by any two of the variables pressure, volume and temperature.

is: a continuous two-dimensional surface formed by plotting the pressure, volume and temperature of every equilibrium state of the substance on three perpendicular axes. Each point on the surface thus represents a possible equilibrium state, and the whole surface may be regarded as a representation of the equation of state of the relevant amount of that substance. [P7.2, P7.3, P7.4]

for an ideal gas is: a graphical representation of the equation of state of an ideal gas for a fixed value of [P7.2, P7.3, P7.4]

is also referred to: as the equilibrium surface, though this term may also be applied to more general systems for which and are not appropriate thermodynamic coordinates. [P7.2, P7.3, P7.4]

often is drawn: in two-dimensional projections in which is plotted against against or against [P7.2, P7.3, P7.4]