Clueless on this chem problem. please help!?

25 mL of liquid nitrogen (density 0.807 g/mL) is poured into a cylindrical container with a radius of 11.5 cm and a length of 21.3 cm. the container initially only contains air (molar m 28.8 g/mol) at a pressure of 760 mmHg and a temperature of 285 K. if the liquid nitrogen completely vaporizes what is the total force in pounds on the interior of the container at 285 K?