1. mole fraction)
X
= 0.1 1
0.1 0.9
A a B b C
c
A(XA) = a
a + b + c
B(XB) = b
a + b + c
C (XC) = c
a + b + C
1
XA + XB + Xc = 1
= X 100
concept 2
1.
2.
1 A 0.6 B 0.3 C
0.8
= A + B +
C
= 0.6 + 0.3 + 0.8
= 1.7
A(XA) = 0.6 = 0.35
1.7
B(XB) = 0.3 = 0.18
1.7
C(Xc) = 0.8 = 0.47
1.7
2 C12H22O11) 25 H2O 60 H = 1,C = 12
,O = 16)
C12H22O11 = mol C12H22O11
mol C12H22O11 + mol H2O
C12H22O11 = (12X12)+22+(11X16)
= 144+ 22+ 176
= 342

2. mol C12H22O11 = 25 g C12H22O11 X 1 mol C12H22H11
342 g
C12H22O11
= 0.073 mol
H2O = (2 X 1) + 16
= 18
mol H2O = 60 g H2O X 1 mol H2O
18 g H2O
= 3.75 mol
C12H22O11 = 0.073
0.073 + 3.75
= 0.073
3.823
= 0.019
H2O = mol H2O
mol C12H22O11 + mol H2O
H2O = 3.75
0.073 + 3.75
= 0.981
3 90 175.5
(H = 1 , O = 16 , Na = 23
, Cl = 35.5)
H2O = 90 = 90 = 5
(2X1)+ 16 18
NaCl) = 175.5 = 175.5 = 3
23 + 35.5 58.5
= 5 + 3 = 8
X = 5 = 0.625
8
X = 3 = 0.375
8
= X 100
= 0.375 X 100 = 37.5
(part per million ppm) (part per
billion ppb)
1
1
HCl 3 ppm 1,000,000
HCl 3
3 ppm 1 g)
106
3 g)
10 ppm 1
cm3
)
10 cm3
)

3. 0.2 ppb 1
109
0.2
ppm ( = X 106
ppb ( = X 109
ppm ( = X 106
ppb ( = X 109
4
100 0.001
ppm
ppm = g) X 106
g)
= 0.001 (g) X 106
100 (g)
= 0.001 (g) X 106
100 (g)
= 1X10-5
X106
10 ppm