A piston-cylinder device contains an ideal-gas mixture of 3 kmol of He gas and 7 kmol of

Question:

A piston-cylinder device contains an ideal-gas mixture of 3 kmol of He gas and 7 kmol of Ar gas at 50oC and 400 kPa. Now the gas expands at constant pressure until its volume doubles. The amount of heat transfer to the gas mixture is
(a) 6.2 MJ
(b) 4.2 MJ
(c) 27 MJ
(d) 10 MJ
(e) 67 MJ