Since Methane is assumed an ideal gas, we need to know its moles in each streams.
Therefore, we can use the ideal gas law to find the mole in the container by:
P V=nRT ⇒ n=PV/R T
n=no of moles of the gas = mass/molar mass
Molar mass o f CO2=44g/mol, mass = 44g
P= 25bar = 101000X25Pa=2.5x106Pa
V = 20L = 20dm3 = 0.02m3
T=100C=373K
R=8.314J/mol.K
n1= 2.5x106Pa x 0.02m3 / 8.314J/mol.K x 373K
n1 = 16.1mols
Similarly for stream 2, we have n2 which is
P=1bar = 100000Pa
T= 100C= 373K
V=200L = 0.02m3
n2= 1x105Pa x 0.02m3 / 8.314J/mol.K x 373K
n1 = 0.645mol
So the new stream is an addition of these two streams of methane which has
n3 = n1 + n2 =16.75mols of methane
T=?
V=200L=0.02m3
P = 25Bar = 2.5x106Pa
T= PV/nR
T = 2.5x106Pa x 0.02m3 / 16.75 x 8.314
T=359K
So the final temperature of the gas in the tank is 359K