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Question
50 m3 of saturated vapour is cooled down from 30°C to 20°C. Find the mass of the water condensed. The absolute humidity of saturated water vapour is 30 g m−3 at 30°C and 16 g m−3 at 20°C.
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Solution
We Know that 1 `"m"^3` of air contains 30 g of water vapour at `30^circ`C.
So, amount of water vapour in 50 `"m"^3` of air at `30^circ`C = (`30 xx 50`) g = 1500 g
Also , 1 `"m"^3` of air contains 16 g of water vapour at `20^circ "C"`.
Amount of water vapour in 50 `"m"^3` of air at `20^circ`C. = `(16 xx 50)` g = 800 g
Amount of water vapour condensed = (1500 - 800) g = 700 g
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