To simplify our solution for this probelm we first assume that the gas we are dealing with is an ideal gas. Given that it is ideal we can proceed the solution using the formula: PV=nRT where P is pressure (203KPa), V is volume (20.0 L), n is moles (required), T is absolute temperature (373K) and R is the gas constant ( 8.31 l-kpa/m-k). Plug in the given to the respective variables and you should get 3.28 moles of the gas sample.
