Chemical Thermodynamics Question 35
Question: The volume of a gas decreases from $ 500,cc $ to $ 300,cc $ when a sample of gas is compressed by an average pressure of 0.6 atm. During this process 10 J of heat is liberated. The change in internal energy is [Pb. PMT 2000]
Options:
A) - 2.16 J
B) 12.156 J
C) 2.16 J
D) 101.3 J
Show Answer
Answer:
Correct Answer: C
Solution:
Here: Change in Volume $ (V)=500-300=200cc=0.2,litre, $
Pressure $ (P)=0.6,atm $ and heat liberated (q) = 10J Work done $ (W)=P\Delta V=(0.2\times 0.6)=0.12,litre-atm $
But $ 1,litre-atm=101.3,J $ . hence $ W=0.12\times 101.3=12.156,J $ .
We also know that heat is liberated, therefore it would be negative. Thus change in $ \Delta E=q+W=-10+12.16=2.16,J $ .
