What is the average kinetic energy of the molecules in a gas at 273K?

Question

108873 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2014-07-31T23:32:46

The average kinetic energy of the molecules is 5.66 × 10⁻²¹ J.

According to Kinetic Molecular Theory, the average kinetic energy of gas molecules is a function only of temperature.

The formula is

$K E = \frac{3}{2} k T$ $KE = 3/2kT$

where $T$ $T$ is the Kelvin temperature and $k$ $k$ is Boltzmann's constant.

$KE = 3/2 × 1.381 × 10⁻²³ "J·K⁻¹" × 273"K"$ = 5.66 × 10⁻²¹ J

For a mole of molecules, the average kinetic energy is

$(5.66 × 10⁻²¹"J")/(1"molecule") × (6.022 × 10²³"molecules")/(1"mol")$ = 3.41 ×10³ J/mol = 3.41 kJ/mol