CN BNG PHA TRONG H MT CU T

Chng 5

1. c im ca qu trnh chuyn pha trong h mt cu t

Trong cc h mt cu t, cc pha ring bit u l cng mt cht cc trng thi tp hp khc nhau nh rn, lng v kh

trng thi rn th c nhiu dng th hnh khc nhau th mi dng th hnh l mt pha

C hai phng php kho st cc h, nhit ng: Phng php gii tch phng php gin trng thi

2. Phng trnh Clapeyron

A () A ()

LdpdT VT

L: l nhit qu trnh pha hoc nhit chuyn pha

V = V() - V()

3. p dng phng trnh Clapeyron cho cc trng hp chuyn pha

3.1. H rn - lng

Qu trnh nng chy hu ht cc cht u km theo tng th tch ca chng, c ngha l Vl - Vr >0

> 0

l r

nc

T(V V )dTdp L

dTdp

3. p dng phng trnh Clapeyron cho cc trng hp chuyn pha

3.2. H rn -hi

Phng trnh Clapeyron

dT Ldp T V

H H Hncth hh

Phng trnh Clausius dp LdT TVh

2

dlnp HdT RT

4. Mt s gin pha c bn

4.1. Gin pha ca nc

ng OK: ng ha hi

nhng nhit T > TK s chuyn pha t lng sang hi l lin tc khng cgii hn phn chia pha

ng OA l ng thng hoa

ng OB l ng nng chy

ng OC l ng qu lnh

4.2. Gin pha ca Lu hunh

im O l im ba khng bn ng vi cn bng khng bn ca lu hunh lng qu lnh, tinh th qu nng v hi lu hunh qu bo ha trn tinh th rn

4. Mt s gin pha c bn

4. Mt s gin pha c bn

4.3. Gin pha ca Cacbon