A constant pressure process greater than the critical pressure is represented by line PQ. Thereis no definite change in phase from liquid to vapor and no definite point at which there is achange from the liquid phase to the vapor phase. For pressures greater than the critical pressure,the substance is usually called a liquid when the temperature is less than the critical temperature(705.47F) and a vapor or gas when the temperature is greater than the critical temperature. Inthe figure, line NJFB represents the saturated liquid line, and the line NKGC represents thesaturated vapor line.