Dilution Problems
Examples of Dilution Problems
DILUTE
HCl
HCl
14M
2M
250mL
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Example 1:
STOCK
mol
C1V1
=
=
Dilute to 5% Æ 10mL
C1V1 = C 2V2
(30%)V1 = (50%)(10mL)
50
V1 =
30
= 1.67 mL
= 1.7 mL of 30% H2O2
mol
C2V2
C1V1 = C 2V2
(14 M )V1 = 2 M (250mL)
500
V1 =
mL
14
= 35.7 mL
= 36mL of 14M HCl
Acid Æ water
Example 2
H2O2 Æ 30% Æ 250mL
Example 3
10mL
(A&W)
Suction pump
3.60 g
Methanoic acid
HCOOH
100mL
250mL
mass
MR
3.6 g
=
46 g / mol
= 0.07826
moles =
pipette
250mL
1 – fill about half the volumetric flask
2 – pipette the amount of acid
3 – add a small amount of water until
correct
4 – stir & shake to make sure the
concentration is even throughout
n
v
(0.07826)
c=
(0.1)
= 0.7826 g / mol
c=
C1V1 = C 2V2
(0.7826)(10) = C 2 (250)
0.0313 = C 2