Question

A vessel has 6 g of oxygen at pressure P and temperature 400 K. A small hole is made in it so that oxygen leaks out. How much oxygen leaks out if the final pressure is $\frac{P}{2}$ and temperature 300 K ?

• A. 5 g
• B. 4 g
• C. 2 g
• D. 3 g

Answer 1

Answer: (C)

2 g

Answer 2

$PV = \frac{m}{M}RT$ (for m grams of gas) ….. (i)

$P`V = \frac{m`}{M}RT`$…. (ii)

Dividing equations (ii) by (i) we get $\frac{p`}{p} = \frac{m`}{M}\frac{T`}{T}$

$m` = \frac{P`}{P} \times \frac{T}{T`} \times m = \left( \frac{P/2}{P} \right) \times \frac{400}{300} \times 6 = 4g$

$\therefore$Mass of oxygen leaked

$\Delta m = m - m` = 6 - 4 = 2g$