A constant-volume tank contains 1 kmol of methane (CH4) gas and 3 kmol of O2 at 25oC

Question:

A constant-volume tank contains 1 kmol of methane (CH4) gas and 3 kmol of O2 at 25oC and 100 kPa. The contents of the tank are ignited, and the methane gas burns completely. If the final temperature is 700oC, determine
(a) The final pressure (P2) in the tank and
(b) The heat transfer during this process.