Question:
A gas mixture consists of 3 moles of oxygen and 5 moles of argon at temperature $T$. Assuming the gases to be ideal and the oxygen bond to be rigid, the total internal energy (in units of RT) of the mixture is:
Correct Option: 1
Solution:
(1) Total energy of the gas mixture,
$E_{\text {mix }}=\frac{f_{1} n_{1} R T_{1}}{2}+\frac{f_{2} n_{2} R T_{2}}{2}$
$=3 \times \frac{5}{2} R T+\frac{5}{2} \times 3 R T=15 R T$