Question

Two balloons are filled, one with pure He gas and the other with air. If the pressure and temperature in both the balloons are same the number of molecules per unit volume is 

(a) more in the He filled balloon 

(b) more in the air filled balloon. 

(c) same in both the balloon. 

(d) in the ratio 1 : 4.

Answer 1

(c) same in both the balloons.

Assuming ideal gas behavior, the number of moles per unit volume \(\frac{n}{V} = \frac{P}{RT}\) is Since P and T are same in both the balloon, \(\frac{n}{V}\) is also same in both.