Added by Thraxas on August 31, 2001 at 00:03:59:
PV=nRT
Where P=pressure in atmospheres (or pascals), V=volume in liters or milliliters, n= number of moles (1 mol= 6.02*10^23), R= ideal gas constant (0.0821 liters-atm/mol-kelvin), and T= temperature in Kelvin.
Use this formula to find the missing value for a gas at STP.