InterviewSolution
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InterviewSolution
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Find the mass of all molecules leaving one square centimetre of water surface per second into a saturated water vapour above it at a temperature `t = 100 ^@C`. It is assumed that `eta = 3.6 %` of all water vapour molecules falling on the water surface are retained in the liquid phase. |
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Answer» In equilibrium the number of "liquid" molecules evaporoting must equals the number of "vapour" molecules condensing. By kinetic theory, this number is `eta xx (1)/(4) n lt v gt = eta xx (1)/(4) n xx sqrt((8)/(pi)(kT)/(m))` Its mass is `mu = m xx eta xx n xx sqrt((kT)/(2 pi m)) = eta n k T sqrt((m)/(2 pi kt))` `=eta p_0 sqrt((M)/(2 pi RT)) = 0.35 g//cm^2.s.` where `p_0` is atmospheric pressure and `T = 373 K` and `M` = molecular weight of water. |
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