Question

At a constant volume the specific heat of a gas is $0.075$ and its molecular weight is $40$. The gas is :

• A. Monoatomic
• B. Diatomic
• C. Triatomic
• D. None of these

Answer 1

Answer: (A)

We know that,
Molar heat capacity at constant volume,
$C_v=$ Specific heat at constant volume $\times$ Mol. wt.
$=0.075\times 40=3.0cal$
$\because C_p-C_v=R$
or $C_p=R+C_v=2+3=5$
Now, $\frac{C_p}{C_v}=\gamma ;$
$\therefore \gamma =\frac{5}{3}=1.66$
This value shows that the gas is monoatomic.