Question

The ratio of kinetic energy of 1 g of $H_2$ and 2 g of ${CH}_4$ at the same temperature will be:

• A. 1:4
• B. 4:1
• C. 1:2
• D. 2:1

Answer 1

Answer: (B)

4:1

The kinetic energy of a gas molecule is independent of its molar mass and at constant temperature, the kinetic energy of a gas molecule is constant.
The ratio of kinetic energy of 1 g of $H_2$ and 2 g of ${CH}_4$ at the same temperature will be equal to the ratio of their number of moles.
The number of moles of hydrogen are $\frac{1g}{2g/mol}=0.5mol$
The number of moles of methane are
$\frac{2g}{16g/mol}=0.125mol$
The ratio of the number of moles of hydrogen to the number of moles of methane are
$\frac{0.5}{0.125}=4:1$
Hence, the ratio of kinetic energy of 1 g of $H_2$ and 2 g of ${CH}_4$ at the same temperature will be 4:1.