Question

At what temperature will the total KE of 0.3 mol of He be the same as the total KE of 0.4 mol of Ar at 400 K?
(1) 533 K (2) 400 K (3) 346 K (4) 300 K

Answer 1

Dear student

$$\begin{gathered} K{E}_{He}=K{E}_{Ar} \\ KE=\frac{3nRT}{2} \\ \frac{K{E}_{He}}{K{E}_{A{r}_{}}}=\frac{0.3\times T}{0.4\times 400}=1 \\ T=\frac{1600}{3}=533.3 \end{gathered}$$