Question

A vessel of volume V = 30 l is separated into three equal parts by stationary semipermeable thin particles (Fig. 61).

The left, middle, and right parts are filled with mH2 = 30 g of hydrogen, mO2 = 160 g of oxygen, and mN2 = 70 g of nitrogen respectively. The left partition lets through only hydrogen, while the right partition lets through hydrogen and nitrogen.

What will be the pressure in each part of the vessel after the equilibrium has been set in if the vessel is kept at a constant temperature T = 300 K?

Answer 1

Since hydrogen diffuses through all the partitions, it uniformly spreads over the entire vessel, and in all the three parts of the vessel, the pressure of hydrogen is

(if a gas penetrates through a partition, its pressure on both sides of the partition must be the same in equilibrium).

Nitrogen can diffuse only through the right partition, and hence will fill the middle and right parts of the vessel (see Fig. 61) having the volume (2/3)V. The pressure of nitrogen is

Oxygen does not diffuse through the partitions, and its pressure in tin middle part of the vessel is

According to Dalton'* law, the pressure in a part of a vessel is equal to the sum of the partial pressures of the gases it contains: