where 
is the pressure of the gas, 
is its volume, 
is the amount of gas (expressed in moles), 
is the molar gas constant and 
is the absolute temperature. [P7.2, P7.3, P7.4, P7.5]
is: a gas that obeys the ideal gas equation of state, where is the pressure of the gas, is its volume, is the amount of gas (expressed in moles), is the molar gas constant and is the absolute temperature. [P7.2, P7.3, P7.4, P7.5]
exists: only as an idealized entity, but is well approximated by a real gas at sufficiently low density. [P7.2, P7.3, P7.4, P7.5]
Copyright 1997, The Open University