A sample of nitrogen gas is bubbled through liquid water at $25^{o} C$ and then collected in a volume of $750 c c$ . The total pressure of the gas which is saturated with water vapour, is found to be $740 m m$ at $25^{o} C$ . The vapour pressure of water at this temperature is $24 m m$ . How many moles of nitrogen are in the sample?

Open in App

Solution

$T = 25^{o} C = 298 K$

$V = 750 c c$

$P_{t o t a l} = 740 m m$ with Vapour press of water $= 24 m m$

$P$ water vapour $+ P_{N_{2}} = P_{t o t a l}$

$24 + P_{N_{2}} = 740 m m$

$P_{N_{2}} = 716 m m$

$P V = n R T$

$n = \frac{P V}{R T} = \frac{\frac{716}{760} \times 750 \times 10^{- 3}}{0.0821 \times 298 K} = 0.0288 m o l e s$

Suggest Corrections

Similar questions

Q. A sample of air contains nitrogen, oxygen and saturated with water vapour under a total pressure of

640

mm. If the vapour pressure of water at that temperature is

40

mm and mole ratio of

N_{2}

O_{2}

3 : 1

, the partial pressure of nitrogen in the sample is:

Q. A vessel has nitrogen gas and water vapour in equilibrium with liquid water at a total pressure of

1

atm. The partial pressure of water vapours is

0.3

atm. The volume of this vessel is reduced to one-third of the original volume, at the same temperature, then find total pressure in atm of the system. (Neglect volume occupied by liquid water)

A sample of air contains nitrogen, oxygen and saturated with water vapour under a total pressure of 640 mm. If the vapour pressure of water at that temperature is 40 mm and the molecular ratio of $N_{2} : O_{2}$ is 3 : 1. Find the partial pressure of nitrogen in the sample.