The universal gas law, pv = nrt, describes the relationship among the pressure, volume, and temperature of a gas. P = pressure v = volume t = temperature (kelvin) n = number of moles (quantity of gas particles) r = universal gas constant at a constant temperature of 1 k, the pressure and volume of 1 mole of gas vary inversely. P = startfraction uppercase r over uppercase v endfraction use the values in the table to find the value of r. Es001-1. Jpg r =.