A gas in a piston-cylinder assembly undergoes two processes in series. From state 1 to state 2 there is energy transfer by heat to the gas with a magnitude of 800 kJ. The second process, from state 2 to state 3, is constant-pressure compression at 400 kPa during which there is a heat transfer from the gas with a magnitude of 450 kJ. The following data are also known: U2 = 2000 kJ and U3 =3500 kJ. Neglecting changes in in kinetic and potential energy, calculate the change in volume of the gas during process 2-3, in m³.