One kilogram of air is allowed to expand reversible in a container behind a piston in such a way that the temperature remains constant at 260C while...

One kilogram of air is allowed to expand reversible in a container behind a piston in such a way that the temperature remains constant at 260°C while the volume is doubled. The piston is then moved in and the heat rejected by the air reversibly at constant pressure until the volume is the same as it was initially.Calculate (i) The net heat flow (ii) The overall change in entropy