Thermodynamics, Statistical Physics, and Quantum Mechanics

THERMODYNAMICS AND STATISTICAL PHYSICS 165

be the sublimation rate. Taking the average velocityfromProblem4.13,

weget

where is themass of ahydrogen molecule, and substituting

we may rewrite(S.4.59.2) as

Gas Mixture Condensation (Moscow Phys-Tech)

Considerthree parts of theplot (seeFigure S.4.60). At there is a

regular gasmixture (nocondensation). At one of thegases

is condensing; let us assume for now it is oxygen (it happens to be true).

At they are bothcondensing, andthere is no pressurechange. Let

us write

Here is thepartial nitrogenpressure at _ is thesaturation
vapor pressure of oxygen, and is thesaturatedvapor pressure ofnitrogen
(1 atm) at Between and nitrogen is a gas, andsince the

Using (S.4.60.3) anddividing(S.4.60.1) by (S.4.60.2), we have

yielding

temperature isconstant,

4.60