In the following take cv = 20.8 and cp = 29.1 j mol^-1 degree c^-1 for nitrogen gas: three moles of nitrogen at 30degree c, contained in a rigid vessel, is heated to 250 degree c. how much heat is required if the vessel has a negligible heal capacity? if the vessel weighs 100 kg and has a heat capacity of 0.5 kj kg^-1 degree c^-1, how much heal is required? four moles of nitrogen at 200degree c is contained in a piston/cylinder arrangement. how much heat must be extracted from this system, which is kept at constant pressure, to cool it to 40degree c if the heat capacity of the piston and cylinder is neglected?