Geoscience Reference
In-Depth Information
Sol.1(lb)%Strengt
× (
hhSol.1)
Sol.2(lb)%StrengthSol.
× (
2)
+
%Strength
of mixture
100
100
Solution1(lb)Solution2(lb)
=
×100
(24.99)
+
■
EXAMPLE 24.70
Problem:
If 25lb of a 10% strength solution are mixed with 40 lb of a 1% strength solution, what is
the percent strength of the solution mixture?
Solution:
Sol.1(lb)%Strengt
× (
hhSol.1)
Sol.2(lb)%StrengthSol.
× (
2)
+
%Strength
of mixture
100
100
Solution1(lb)Solution2(lb)
=
×
100
+
(
25 lb)(0.1)
+
+
(40lb)(0.01)
=
×
100
25 lb
40 lb
2
.. 5lb 0.4 lb
65 lb
+
=
= 4.%
Key Point:
Percent strength should be expressed in terms of pounds chemical per pounds solu-
tion. That is, when solutions are expressed, for example, in terms of gallons, the gallons should be
expressed as pounds before continuing with the percent strength calculations.
24.10.6 s
olution
m
ixtures
and
t
arget
p
erCent
s
trength
When two different percent strength solutions are mixed in order to obtain a desired quantity of
solution and a target percent strength, we use Equation 24.99 and fill in the given information. Then,
we find for the unknown,
x
.
■
EXAMPLE 24.71
Problem:
What weights of a 3% solution and a 6% solution must be mixed to make 800 lb of a 4%
solution?
Solution:
Sol.1(lb)%Strengt
× (
hhSol.1)
Sol.2(lb)%StrengthSol.
× (
2)
+
%Strength
of mixture
100
100
Solution1(lb)Solution2(lb)
=
×
100
+
(( b)(0.03)
x
+−
×
800
(800
x
lb)(0.06)
4
=
100
lb
4
100
(
800
)
=
003 8006
.
x
+
−
.
x
32 003 8
003 4
=−
.
x
+
.
x
=
x
=
467 lb of 3%solution
800
−=
467
333 lb of 6%
solution
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