1. A 2.00-mol sample of a diatomic ideal gas expands slowly and adiabatically fr

Question

1. A 2.00-mol sample of a diatomic ideal gas expands slowly and adiabatically from a pressure of 5.06 atm and a volume of 13.0 L to a final volume of 30.2 L.

(a) What is the final pressure of the gas?
atm

(b) What are the initial and final temperatures?

(c) Find Q for the gas during this process.
kJ

(d) Find Eint for the gas during this process.
kJ

(e) Find W for the gas during this process.
kJ

2. During the compression stroke of a certain gasoline engine, the pressure increases from 1.00 atm to 20.5 atm. The process is adiabatic and the air–fuel mixture behaves as a diatomic ideal gas.

(a) By what factor does the volume change?
Vfinal =  Vinitial

(b) By what factor does the temperature change?
Tfinal =  Tinitial

Assume the compression starts with 0.016 mole of gas at 28.5°C.

(c) Find the value of Q that characterizes the process.
J

(d) Find the value of Eint that characterizes the process.
J

(e) Find the value of W that characterizes the process.
J

Explanation / Answer

Q1.

a)
Pf = Pi(Vi/Vf)^
= 5.06*(13/30.2)^1.40
= 1.55 atm

b)
Ti = PiVi/nR
= (5.06*1.013*10^5*13*10^-3)/(2*8.314)
= 400.7K

Tf = (1.55*1.013*10^5*30.2*10^-3)/(2*8.314)
= 285.2K

c)
Q=0
= 1.4, Cv = 5/2 R
Eint = nCvT = 2*[(5/2)*8.314]*(285.2-400.7)
= -4.8 kJ
W = Eint - Q = -4.8 kJ

Please post other question separately

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