Page 3 - 01 PG Bab 01 Sifat Koligatif.pmd

A. Pilihan Ganda 2. M CH COOH = 60 g/mol
3
r
M H O = 18 g/mol
r 2
1. Jawaban: e
n = = 0,25 mol = n
CH COOH 1
3
m= ×

n = = 5 mol = n
H O 2
2
= ×

x = = = 0,05
= 0,1 m CH COOH + +
3

2. Jawaban: c x H O = 1 – 0,05 = 0,95
2

3. Dalam 100 gram larutan urea 20% terdapat 20 gram
x =
metanol + urea dan 80 gram air.

=
+ Jumlah mol air =
− = 4,44 mol
= 0,64
Jumlah mol urea = = 0,33 mol
Berat metanol = 0,64 × 100% = 64%
−
3. Jawaban: c
1 molal artinya 1 mol zat terlarut dalam 1.000 gram x urea = +

= 0,069
pelarut.
4. Dalam 100 gram larutan glukosa 12% terdapat:
4. Jawaban: d
Fraksi mol NaOH = 0,05 glukosa 12% = × 100 g = 12 gram
Fraksi mol H O = 1 – 0,05 = 0,95
2
M air = 18 air (pelarut) = 100 – 12 = 88 gram
r
×

Molalitas (m) = = 2,92 Jumlah mol glukosa =
− = 0,067 mol
×

Massa pelarut = 88 gram = 0,088 kg
5. Jawaban: c

46% massa etanol berarti 46 gram etanol dan m = = = 0,76 mol kg –1

54 gram air.
5. M HCl = 36,5 g/mol
r
m= ×
Massa larutan = 1.000 ml × 1,1 gram/ml
= 1.100 gram

= ×
Massa HCl = × 1.100 gram
= 18,52 molal
= 200,75 gram
Massa H O = (1.100 – 200,75) gram
B. Uraian 2
= 889,25 gram
1. Larutan 6 gram urea dalam 200 gram air.
n HCl =
= 5,50 mol

Jumlah mol urea = − = 0,1 mol

n H O = = 49,96 mol
Massa pelarut = 200 gram = 0,2 kg 2

m = = = 0,5 mol kg –1 x = = 0,1
HCl +
x = 1 – 0,1 = 0,9
H O
2
2 Sifat Koligatif Larutan