As shown in fig. p3.119, a piston-cylinder assembly whose piston is resting on a set of stops contains 0.5 kg of helium gas. initially at 100 kpa and 25 degree c. the mass of the piston and the effect of the atmospheric pressure acting on the piston are such that a pressure of 500 kpa is required to raise it. how much energy must be transferred by heat to the helium, in kj. before the piston starts rising? assume ideal gas behavior for the helium.