Name: ______________________________
Class No.: _______________
Quiz: Thermodynamics
Time allowed: 15 minutes
Molar gas constant R= 8.31 J/mole, molecular mass of O2 and H2 are 32 gm/mole and 2 gm/mole.
1.
P
I (P1, V1, T1)
II (P1, V2, T3)
a.
If T1 = T2 = 27oC, V1= 2 lit, V2=4 lit,
how much work is done by the 64
gm of oxygen at 27oC (constant)
Working gas is O2
when it expands from 2 lit to 4 lit.,
i.e. I  III directly?
b. How much work is done by the 64
gm of oxygen if I  II III?
III (P2, V2, T2)
V1
2.
V2
V
H2 gas is stored in a 10 lit container at 50 atm pressure, 27oC. Some H2 is used and the
pressure decreases to 10 atm pressure, 17oC. How much gas is used?
Name: ______________________________
Class No.: _______________
Quiz: Thermodynamics
Time allowed: 15 minutes
Molar gas constant R= 8.31 J/mole, molecular mass of O2 and H2 are 32 gm/mole and 2 gm/mole.
1.
P
I (P1, V1, T1)
II (P1, V2, T3)
c.
If T1 = T2 = 27oC, V1= 2 lit, V2=4 lit,
how much work is done by the 64
gm of oxygen at 27oC (constant)
Working gas is O2
when it expands from 2 lit to 4 lit.,
i.e. I  III directly?
d. How much work is done by the 64
III (P2, V2, T2)
V1
3.
V2
gm of oxygen if I  II III?
V
H2 gas is stored in a 10 lit container at 50 atm pressure, 27oC. Some H2 is used and the
pressure decreases to 10 atm pressure, 17oC. How much gas is used?
Answers
1.
a. W 
M

RT ln
V2 64
4
  8.31  300  ln  3480 J
V1 32
2
M
b.
W I , II , III  0  p1 (V2  V1 ) 

2.

RT
V1
(V2  V1 )
64  8.31  300
 2  10 3  4990 J
3
32  2  10
pV  nRT  n 
pV
pV
M pV
 pV


 M   1 1  2 2
RT
 RT
R  T1
T2

  3.12  10 2 kg
