Q. Two balloons are filled, one with pure He gas and the other by air, respectively. If the pressure and temperature of these balloons are same, then the number of molecules per unit volume is
A) More in the He filled balloon
B) Same in both balloons
C) More in air filled balloon
D) In the ratio of 1:4
Explanation
(b) Ideal gas equation can be written as
$pV = nRT$ ...(i)
From Eq. (i), we have
$\frac{n}{V} = \frac{p}{RT} =$constant
So, at constant pressure and temperature, all gases will contain equal number of molecules per unit volume.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.