Compressed carbon dioxide gas is contained in a 5 L rigid cy

Compressed carbon dioxide gas is contained in a 5 L rigid cylinder. Its initial temperature and pressure are 500 degrees C and 3 atm (absolute), respectively. If a valve is opened and half the gas is allowed to escape and the pressure in the tank drops to 1.2 atm (absolute), what is the final temperature of the gas?

Solution

At State 1

P1 * V1 = m * R * T1

3 * 101325 * 5 * 10^-3 = m * 188.9 * 773

m = 0.010409 kg

Half the gas is allowed to escape therefore final mass = 0.0052045 kg

P2 * V2 = m * R * T2

T2   =   1.2 * 101325 * 5 * 10^-3 / (0.0052045 * 188.9)     =   618.382 K