Air at a temperature of 20oC and 800 mm Hg has a relative humidity of 80% Calculate i) The molal humidity of the air ii) Weight of water condensed from 1000 liters of the original wet air when it is...

Air at a temperature of 20oC and 800 mm Hg has a relative humidity of 80% Calculate

i) The molal humidity of the air
ii) Weight of water condensed from 1000 liters of the original wet air when it is reduced

to 10oC and pressure increased to 2000 mm Hg. by Condensing out some of the water.
Vapour pressure of water at 20oC – 17.5 mm Hg.
Vapour pressure of water at 10oC – 9.2 mm Hg.