A container in the shape of a cube 20.0 cm on each edge contains air (with equivalent molar mass 28.9 g/mol) at atmospheric pressure and temperature 330 K. Find (a) the mass of the gas, (b) the gravitational force of the Earth exerted on it, and (c) the force it exerts on each face of the cube. (d) Why does such a small sample exert such a great force?