the answer is not -891 and im confused because i thought my work was correct.

A piston-cylinder assembly contains 2lb of water, initially at 100lbf/in2 and 600F. The water undergoes two processes in series: a constant-pressure process followed by a constant volume process. At the end of the constant-volume process, the temperature is 300F and the water is a two-phase liquid-vapor mixture with a quality of 50%. Neglect kinetic and potential energy effects. Determine the work and heat transfer for each process, all in Btu. Your answer is incorrect. Determine the heat transfer for the constant-pressure process, in Btu. Q12= Hint Attempts: 2 of 5 used Part C The parts of this question must be completed in order. This part will be available when you complete the part above