P: Pressure - Atmospheres (atm), torr, mmHg

V: Volume - Liters (L)

n: Amount of gas - moles (mol)

T: Temperature - Kelvin (K)

R: Ideal gas constant = 0.0820057 L-atm/mol-K

                          = 62.3243 L-torr/mol-K

                          = 62.3243 L-mmHg/mol-K

Next:  "Kinetic Molecular Theory"