What is the temperature at which the kinetic energy of 0.3 moles of helium is equal to the kinetic energy of…
What is the temperature at which the kinetic energy of 0.3 moles of helium is equal to the kinetic energy of 0.4 moles of argon at $400 \mathrm{~K}$ ?
$400 \mathrm{~K}$
$873 \mathrm{~K}$
$533 \mathrm{~K}$
$300 \mathrm{~K}$
Solution
Number of moles of helium $=0.3$
Number of moles of argon $=0.4$
We know that $\mathrm{KE}=n R T$
$\mathrm{KE}$ of helium $=0.3 \times R \times T$
$\mathrm{KE}$ of argon $=0.4 \times R \times 400$
According to question
$\mathrm{KE}$ of helium $=\mathrm{KE}$ of argon
$
\begin{aligned}
0.3 \times R \times T & =0.4 \times R \times 400 \\
T & =533 \mathrm{~K}
\end{aligned}
$