ideal gas law
According to the ideal gas law, when a gas is compressed into a smaller volume, the number and velocity of molecular collisions increase, raising the gas's temperature and pressure.
equation of state
physics
equation of state, an equation that relates the values of pressure, volume, and temperature of a given substance in thermodynamic equilibrium.
The simplest known example of an equation of state is the one relating the pressure P, the volume V, and the absolute temperature T of one mole of an ideal gas—that is, the ideal gas law PV = RT, in which R is the universal gas constant. Dense real gases, liquids, and solids have more complicated equations of state.