Question

For ideal gas molecules the following quantities have zero average values.

• A. Velocity
• B. Momentum
• C. Kinetic energy
• D. Density

Answer 1

Answer: (A), (B)

Momentum

If in an ideal gas sample you find one molecule with a particular velocity at any instant then because of large and random velocity distribution you can also find another molecule with exactly opposite velocity.
${\overrightarrow{v}}_{av}=0\Rightarrow {\overrightarrow{p}}_{av}=0K.E.=\frac{f}{2}nRT\rho =\frac{PM}{RT}Since,PV=nRTPV=\frac{m}{M}RTPM=\frac{m}{V}RT$