(N/A) The kinetic interpretation of temperature states that the average kinetic energy of gas molecules is directly proportional to the absolute temperature of the gas.
Consider a gas consisting of $N$ molecules,with pressure $P$,volume $V$,and absolute temperature $T$.
The pressure of an ideal gas is given by:
$P = \frac{1}{3} \rho \langle v^2 \rangle$
Since density $\rho = \frac{M}{V}$ and total mass $M = N m$ (where $m$ is the mass of one molecule):
$P = \frac{1}{3} \left( \frac{N m}{V} \right) \langle v^2 \rangle$
Multiplying both sides by $V$:
$PV = \frac{1}{3} N m \langle v^2 \rangle$
We can rewrite this as:
$PV = \frac{2}{3} N \left( \frac{1}{2} m \langle v^2 \rangle \right)$
Since the average kinetic energy of a single molecule is $K_{avg} = \frac{1}{2} m \langle v^2 \rangle$,we have:
$PV = \frac{2}{3} N K_{avg}$
From the ideal gas law,$PV = N k_B T$ (where $k_B$ is the Boltzmann constant):
$N k_B T = \frac{2}{3} N K_{avg}$
Therefore,$K_{avg} = \frac{3}{2} k_B T$.
This equation shows that the average kinetic energy of gas molecules is directly proportional to the absolute temperature $T$.