Question

The average energy of molecules in a sample of oxgen gas at $ {300 \, K}$ are $ {6.21 \times 10^{-21} \, J}$. The corresponding values at $ {600\, K}$ are

• A. $\ce{6.21 \times 10^{-21} \, J}$
• B. $\ce{8.78 \times 10^{-21} \, J}$
• C. $\ce{4.21 \times 10^{-21} \, J}$
• D. $\ce{12.42 \times 10^{-21} \, J}$

Answer 1

The Correct Option is D

The average kinetic energy of molecules in a sample of oxygen gas is given by
$ {KE_{avg} = \frac{3}{2}kT\, or \, \frac{(KE_{avg})_{1}}{(KE_{avg})_{2}} = \frac{T_{1}}{T_{2}}}$
$ {(KE_{avg})_{1} =6.21 \times10^{-21} J, T_{1} =300 K}$
$ {T_2 = 600 \, K , (KE_{avg})_2 = ?}$
$\therefore \:\:\: {\frac{6.21 \times10^{-21}}{(KE_{avg})_{2}} =\frac{300}{600} =\frac{1}{2}}$
$ {(KE_{avg})_{2} = 12.42 \times10^{-21} J}$