Kinetic Theory Of Gases Question 114

Question: A gaseous mixture contains equal number of hydrogen and nitrogen molecules. Specific heat measurements on this mixture at temperatures below 100 K would indicate that the value of $ \gamma $ (ratio of specific heats) for this mixture is

Options:

A) 3/2

B) 4/3

C) 5/3

D) 7/5

Show Answer

Answer:

Correct Answer: C

Solution:

[c] Below 100 K only translational degree of freedom is considered. Hence $ {\gamma _{mixture}}=\frac{\frac{{\mu _{1}}{\gamma _{1}}}{{\gamma _{1}}-1}+\frac{{\mu _{2}}{\gamma _{2}}}{{\gamma _{2}}-1}}{\frac{{\mu _{1}}}{{\gamma _{1}}-1}+\frac{{\mu _{2}}}{{\gamma _{2}}-1}} $ according to question, $ {\mu _{1}}={\mu _{2}} $ and $ {\gamma _{1}}={\gamma _{2}} $

$ =1+\frac{2}{3}=\frac{5}{3} $

$ \Rightarrow {\gamma _{mix}}={\gamma _{1}}=\frac{5}{3} $