Question

The total kinetic energy of all the molecules of helium having a volume V exerting a pressure P is 1500 J. The total kinetic energy in joules of all the molecules of N₂ having the same volume V and exerting a pressure 2P is –

• A. 3000
• B. 4000
• C. 5000
• D. 6000

Answer 1

Answer: (A)

3000

Answer 2

Gas equation for N₂

(2P) (V) = $\frac{N}{N_{A}}RT$ …..(i)

For He

(P)(V) =$\frac{N'}{N_{A}}RT$ …..(ii)

Divide (i) and (ii), N = 2N¢

1500 = N¢ $\left( \frac{3}{2}KT \right)$ for He,

E = N $\left( \frac{5}{2}KT \right)$ for N₂

̃ E = 500 J