Question

A mixture of ideal gases has 2 moles of Helium, 4 moles of Oxygen and 1 mole of Ozone at absolute temperature $T$. The internal energy of mixture is

• A. $13\text{RT}$
• B. $11\text{RT}$
• C. $16\text{RT}$
• D. $14\text{RT}$

Answer 1

The correct option is C $16\text{RT}$

$E=n\frac{f}{2}RT$

$\begin{array}{cc}{E}_{Total}& =E_{He}+E_{0_2}+E_{0_3}\\ & =\frac{RT}{2}(n_{He}{f}_{He}+n_{o_2}{f}_{0_2}+n_{0_3}{f}_{0_3})\end{array}$

$=\frac{RT}{2}[2\times 3+4\times 5+1\times 6]$

$=\frac{RT}{2}(6+20+6)$

$=\frac{RT\times 32}{2}=16RT$