Chapter 8
Solution
Percent Concentration
LecturePLUS Timberlake
1
Percent Concentration
Describes the amount of solute
dissolved in 100 parts of solution
amount of solute
100 parts solution
LecturePLUS Timberlake
2
Mass-Mass % Concentration
mass/mass % = g solute
x 100%
100 g solution
LecturePLUS Timberlake
3
Mixing Solute and Solvent
+
Solute
4.0 g KCl
Solvent
46.0 g H2O
50.0 g KCl solution
LecturePLUS Timberlake
4
Calculating Mass-Mass %
g of KCl
g of solvent
g of solution
=
=
=
4.0 g
46.0 g
50.0 g
%(m/m) = 4.0 g KCl (solute) x 100 = 8.0% KCl
50.0 g KCl solution
LecturePLUS Timberlake
5
Learning Check PC1
A solution contains 15 g Na2CO3 and 235 g of
H2O? What is the mass % of the solution?
1) 15% (m/m) Na2CO3
2) 6.4% (m/m) Na2CO3
3) 6.0% (m/m) Na2CO3
LecturePLUS Timberlake
6
Solution PC1
mass solute
=
15 g Na2CO3
mass solution
=
15 g + 235 g = 250 g
%(m/m) = 15 g Na2CO3
x
100
250 g solution
= 6.0% Na2CO3 solution
LecturePLUS Timberlake
7
Mass-Volume %
mass/volume % = g solute
x 100%
100 mL solution
LecturePLUS Timberlake
8
Learning Check PC2
An IV solution is prepared by
dissolving 25 g glucose
(C6H12O6) in water to make
500. mL solution. What is the
percent (m/v) of the glucose in
the IV solution?
1) 5.0%
2) 20.% 3) 50.%
LecturePLUS Timberlake
9
Solution PC2
1) 5.0%
%(m/v)
=
25 g glucose x 100
500. mL solution
=
5.0 %(m/v) glucose solution
LecturePLUS Timberlake
10
Writing Factors from %
 A physiological saline solution is a 0.85%
(m/v) NaCl solution.
 Two conversion factors can be written for
the % value.
0.85 g NaCl
and 100 mL NaCl soln
100 mL NaCl soln
0.85 g NaCl
LecturePLUS Timberlake
11
% (m/m) Factors
Write the conversion factors for a 10 %(m/m)
NaOH solution
NaOH
and
NaOH soln
LecturePLUS Timberlake
NaOH soln
NaOH
12
% (m/m) Factors
Write the conversion factors for a 10 %(m/m)
NaOH solution
10 g
100 g
NaOH
and
NaOH soln
LecturePLUS Timberlake
100 g
10 g
NaOH soln
NaOH
13
Learning Check PC 3
Write two conversion factors for each of the
following solutions:
A. 8 %(m/v) NaOH
B. 12 %(v/v) ethyl alcohol
LecturePLUS Timberlake
14
Solution PC 3
Write conversion factors for the following:
A. 8 %(m/v) NaOH
8 g NaOH and 100 mL
100 mL
8 g NaOH
B. 12 %(v/v) ethyl alcohol
12 mL alcohol and 100 mL
100 mL
12 mL alcohol
LecturePLUS Timberlake
15
Using % Factors
How many grams of NaCl are needed to
prepare 250 g of a 10.0% (m/m) NaCl solution?
Complete data:
____________ g solution
____________% or (______/_100 g_) solution
____________ g solute
LecturePLUS Timberlake
16
Clculation Using % Factors
250
10.0%
?
g solution
or (10.0 g/100 g) solution
g solute
250 g NaCl soln x 10.0 g NaCl
= 25 g NaCl
100 g NaCl soln
LecturePLUS Timberlake
17
Learning Check PC4
How many grams of NaOH do you need to
measure out to prepare 2.0 L of a 12%(m/v)
NaOH solution?
1) 24 g NaOH
2) 240 g NaOH
3) 2400 g NaOH
LecturePLUS Timberlake
18
Solution PC4
2.0 L soln x 1000 mL = 2000 mL soln
1L
12 % (m/v) NaOH =
12 g NaOH
100 mL NaOH soln
2000 mL x 12 g NaOH
=
100 mL NaOH soln
LecturePLUS Timberlake
240 g NaOH
19
Learning Check PC5
How many milliliters of 5 % (m/v) glucose
solution are given if a patient receives 150 g
of glucose?
1) 30 mL
2) 3000 mL
3) 7500 mL
LecturePLUS Timberlake
20
Solution PC5
5% m/v factor
150 g glucose x
100 mL = 3000 mL
5 g glucose
LecturePLUS Timberlake
21