`50cc` of oxygen is collected in an inverted gas jar over water.The atmospheric pressure is 99.4 kPa and the room tempareture is `27^(@)C.`The water level in the jar is same as the level outside . The saturation vapour pressure at`27^(@)C`is 3.4kPa. Calculate the number of moles of oxgen collected in the jar.

Explanation

Pressure inside the tube
= Atmospheric pressure
= 99.4 K Pa
pressure exerted by `O_2` vapour
= Atmospheric pressure V.P.
= 99.4 K Pa - 3.4 K Pa
=96 K Pa
` If number of mole of ` O_2` = n `
Then using gas equation
` 96 xx (10^3) xx 50 xx (10^-6)`
` = n xx 8.3 xx 300`
rArr n= ( 96 xx 50 xx (10^3)/8.3 xx 300)`
` =1.9277 xx(10^-3).`