(perfect gas). A gas in which there is complete absence of cohesive forces between the component molecules; the behavior of such a gas can be predicted accurately by the ideal gas equation through all ranges of temperature and pressure. The concept is theoretical, since no actual gas meets the ideal requirement; carbon dioxide especially lacks conformity. The generalized ideal gas law is derived from a combination of the laws of Boyle and Charles, namely pv = RT, where p is pressure, v is volume, T is absolute temperature and R is the gas constant (p0v0/273.2C).