Question

A vessel, divided into two parts by a partition, contains 4 mol of nitrogen gas at 75°C and 30 bar on one side and 2.5 mol of argon gas at 130°C and 20 bar on the other. If the partition is removed and the gases mix adiabatically and completely, what is the change in entropy? Assume nitrogen to be an ideal gas with CV = (5/2)R and argon to be an ideal gas with CV = (3/2)R.

Answer 1

Answer:

assume nitrogen is an ideal gas with cv=5R/2

assume argon is an ideal gas with cv=3R/2

n1=4moles

n2=2.5 moles

t1=75°C   in kelvin t1=75+273

t1=348K

T2=130°C  in kelvin t2=130+273

t2=403K

u=пCVΔT

U(N₂)+U(Argon)=0

putting values:

=>4x(5R/2)x(Tfinal-348)=2.5x(3R/2)x(T final-403)

by simplifying:

Tfinal=363K