Question

Indicate the correct statement for equal volumes of $N_2\left(g\right)$ and $C{O}_2\left(g\right)$ at 298 K and 1 atm.

• A. The average translational $KE$ per molecule is the same for $N_2$ and $C{O}_2$
• B. the rms speed remains constant for both $N_2$ and $C{O}_2$
• C. Both A and B
• D. None of the above

Answer 1

The correct option is A The average translational $KE$ per molecule is the same for $N_2$ and $C{O}_2$

$PV=nRT\Rightarrow n=\frac{\left(1\right)\left(V\right)}{\left(R\right)\left(298\right)}=\frac{V}{298}\text{For N}{}_2\text{and CO}{}_2\text{the no. of moles are same}\text{Average translational energy =}\frac{3}{2}nRT\text{So, same for both N}{}_2\text{and CO}{}_2\text{.}$