50 cc of oxygen is collected in an inverted gas jar over water. The atmospheric pressure is 99.4 kPa and the room temperature is 27°C. The water level in the jar is same as the level outside. The saturation vapor pressure at 27°C is 3.4 kPa. Calculate the number of moles of oxygen collected in the jar.

Given


Volume of oxygen = 50cc=50cm3=50


Atmospheric pressure Po=99.4kPa=99.4Pa


Temperature =27=300.15K


Saturation vapor pressure Ps=3.4kPa=3.4Pa


According to question water level in the jar is same as level outside. So


Pressure inside the jar = pressure outside the jar


Pressure outside the jar =atmospheric pressure Po


Pressure inside the jar=Po …. (1)


But


Pressure inside the jar is also = vapor pressure of oxygen+ Saturation vapor pressure


Pressure inside the jar=P+Ps …. (2)


From equation (1) and (2), we can write


Po=P+Ps


P=Po-Ps=99.4-3.4=96Pa


Applying ideal gas equation


PV=nRT


Where V= volume of gas


R=gas constant =8.3JK-1mol-1


T=temperature


n=number of moles of gas


P=pressure of gas.




The number of moles of oxygen collected in the jar is 1.9310-3.


1