States of Matter - Result Question 39
####39. Helium atom is two times heavier than a hydrogen molecule. At $298 K$, the average kinetic energy of a helium atom is
(a) two times that of a hydrogen molecule
$(1982,1 M)$
(b) same as that of a hydrogen molecule
(c) four times that of a hydrogen molecule
(d) half that of a hydrogen molecule
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Solution:
- According to kinetic theory, average kinetic energy $(E)=\frac{3}{2} k _B T$ where, $k _B$ is Boltzmann’s constant. Since, it is independent of molar mass, it will be same for $He$ and $H _2$ at a given temperature.
