Colligative Properties of Diluted Solutions

Raoult

H2O (l) H2O (g) p( )Pa, kPa

pp p p

Raoult

Raoult , p = po xA po:,P:

xA+ xB =1p= po xA = po(1- xB)= po - po xB po- p = po xB p = po- p p = po xB p p0

nA>> nB

1000g

p= K bB

1 C5H12M = 72.15 gmol-120.377.31 kPa0.0697g0.891g2.32 kPaRaoultK

K = p0MAK = p0MA = 77.31 kPa72.15 gmol-1 =5578 kPagmol-1 = 5.578 kPakgmol-1

2 293K2.338 kPa6.840 g(C12H22O11)100.0 g

p = p0xA = 2.338 kPa0.996 4 = 2.330 kPa

101.3kPa

Tb = Tb - Tb0 = Kb mB

T0bKb

273 K

(3)(4)Tf

(a) (b)

Tf = Tf0 - Tf = Kf bB

T0b KbT0f Kf

Kf

0.638 g250 g0.079 K

p = i K bBTb = i Kbb B Tf = i Kfb B ABi2 (KCl) AB2A2B, i3 (MgCl2)

0.100molkg-1NaCl NaClABi =2Tf(NaCl) = 20.100 molkg-11.86 Kkgmol 1 =0.372 K Tf(NaCl) = - 0.372

, ,

: PakPa

= cBRT cB (molL-1) R 8.314 JK-1mol-1 T (273 + t)

cos

303.7 mmolL-1 cos 280 ~ 320 mmolL-1 cos 320 mmol L-1 cos 280 mmolL-1

mmolL-1

mmolL-1

50.0 gL-19.00 gL-1 NaCl() (C6H12O6)180 gmol-1

NaCl58.5 gmol-1