Percent Concentration

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 mLLecturePLUS NaOHTimberlake soln

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