Thermodynamics, Statistical Physics, and Quantum Mechanics

time Since againonlychanges alittle, wehave

We may now eliminate from (S.4.10.1),yielding

4.11 Liquid–Solid–Liquid (Moscow Phys-Tech)

a) Since the evaporation is very rapid, the heat tovaporize can only be

obtainedfrom theheat offusion. Therefore, if of waterbecomessolid

and vaporizes, we maywrite

Since thetotalmass we have

If we continuepumping, the ice would, of course,gradually sublimate, but

this process takesmuchlonger, so we can neglect it.

b) The metalcoolsfrom its initialtemperature by transferringheat to
meltsome ice:

where is the temperature change. This may bedeterminedfrom the
sample’s density before it wasplaced in thecalorimeter.Using the thermal
coefficient ofvolume expansion where we have

The temperature difference may be found from(S.4.11.4)

THERMODYNAMICS AND STATISTICAL PHYSICS 95

Just as in the heating phase, the heat loss is proportional to theelapsed