1. General, Organic, and Biological Chemistry Fourth Edition Karen Timberlake 8.4 Solution Concentration Chapter 8 Solutions © 2013 Pearson Education, Inc. Lectures

2. © 2013 Pearson Education, Inc. Chapter 8, Section 4 2 The concentration of a solution  is the amount of solute dissolved in a specific amount of solution.  can be represented as mass percent, volume percent, mass/volume percent, or molarity. Concentration

3. © 2013 Pearson Education, Inc. Chapter 8, Section 4 3  Mass percent (m/m) concentration is the grams of the solute in exactly 100 g of solution (mass solute + mass solvent).  Mass Percent Concentration

4. © 2013 Pearson Education, Inc. Chapter 8, Section 4 4 Suppose we prepared a solution by mixing 8.00 g of KCl (solute) with 42.00 g of water (solvent). Calculating Mass Percent

5. © 2013 Pearson Education, Inc. Chapter 8, Section 4 5 When water is added to 8.00 g of KCl to form 50.00 g of KCl solution, the mass percent concentration is 16.0% (m/m). Mass of Solution

6. © 2013 Pearson Education, Inc. Chapter 8, Section 4 6 Guide to Calculating Solution Concentration

7. © 2013 Pearson Education, Inc. Chapter 8, Section 4 7 A solution is prepared with 15.0 g of Na 2 CO 3 and 235 g of H 2 O. What is the mass percent (m/m) of Na 2 CO 3 in the solution? Learning Check

8. © 2013 Pearson Education, Inc. Chapter 8, Section 4 8 A solution is prepared with 15.0 g of Na 2 CO 3 and 235 g of H 2 O. What is the mass percent (m/m) of Na 2 CO 3 in the solution? Step 1 Determine the quantities of solute and solution. Analyze the Problem. Solution Quantity of SoluteQuantity of SolutionConcentration Type of Solution Problem 15.0 g Na 2 CO 3 + 235 g H 2 O = 250 g Na 2 CO 3 solution ? g Na 2 CO 3 /100 g Na 2 CO 3 solution mass percent (m/m)

9. © 2013 Pearson Education, Inc. Chapter 8, Section 4 9 A solution is prepared with 15.0 g of Na 2 CO 3 and 235 g of H 2 O. What is the mass percent (m/m) of Na 2 CO 3 in the solution? Step 2 Write the concentration expression. Step 3 Substitute solute and solution quantities into the expression and calculate. Solution

10. © 2013 Pearson Education, Inc. Chapter 8, Section 4 10 The volume percent (v/v) is  percent by volume of solute (liquid) in a solution, and  A 7% (v/v) solution contains 7 mL of solute per 100 mL of solution. Volume Percent

11. © 2013 Pearson Education, Inc. Chapter 8, Section 4 11 A bottle contains 59 mL of lemon extract solution. If the solution contains 49 mL of alcohol, what is the volume percent (v/v) of the alcohol in the extract solution? Learning Check

12. © 2013 Pearson Education, Inc. Chapter 8, Section 4 12 A bottle contains 59 mL of lemon extract solution. If the solution contains 49 mL of alcohol, what is the volume percent (v/v) of the alcohol in the extract solution? Step 1 Determine the quantities of solute and solution. Solution Quantity of SoluteQuantity of SolutionConcentration Type of Solution Problem 49 mL alcohol 59 mL extract solution? mL alcohol/100 mL solution volume percent (v/v) Analyze the Problem.

13. © 2013 Pearson Education, Inc. Chapter 8, Section 4 13 A bottle contains 59 mL of lemon extract and 49 mL of alcohol, what is the volume percent (v/v) of the alcohol in the extract solution? Step 2 Write the concentration expression. Step 3 Substitute solute and solution quantities into the expression and calculate. Solution

14. © 2013 Pearson Education, Inc. Chapter 8, Section 4 14  The mass/volume percent (m/v) is widely used for preparation of intravenous solutions and medications.   A 5% mass/volume percent solution contains 5 grams of solute per 100 mL of solution. Mass/Volume Percent

15. © 2013 Pearson Education, Inc. Chapter 8, Section 4 15 Preparation of a Solution: Mass/Volume Percent Water is added to 5.0 g of KI to make 250 mL of KI solution. The mass/volume percent of the solution is 2.0% (m/v) KI solution.

16. © 2013 Pearson Education, Inc. Chapter 8, Section 4 16 Molarity, (Moles/L) Concentrations are frequently measured using molarity (M), a concentration that states the number of moles of solute in exactly 1 liter of solution. If 2.0 moles of NaCl are dissolved in enough water to prepare 1.0 L of solution, the resulting NaCl solution has a molarity of 2.0 M.

17. © 2013 Pearson Education, Inc. Chapter 8, Section 4 17 Molarity, (moles/L) A solution of 2.0 moles of NaCl and water added to the 1-L mark is a 2.0 M NaCl solution.

18. © 2013 Pearson Education, Inc. Chapter 8, Section 4 18 Learning Check What is the molarity of a 0.350 L solution that contains 46 g of KCl?

19. © 2013 Pearson Education, Inc. Chapter 8, Section 4 19 What is the molarity of a 0.350 L solution that contains 46 g of KCl? Step 1 Determine the quantities of solute and solution. Analyze the Problem. Solution Quantity of SoluteQuantity of SolutionConcentration Type of Solution Problem 46 g of KCl 0.350 L KCl solution? M of KCl solution or (? moles KCl/1 L solution) Molarity (M)

20. © 2013 Pearson Education, Inc. Chapter 8, Section 4 20 What is the molarity of a 0.350 L solution that contains 46 g of KCl? Step 1 Determine the quantities of solute and solution. 1 mole of KCl = 74.6 g of KCl Solution

21. © 2013 Pearson Education, Inc. Chapter 8, Section 4 21 What is the molarity of a 0.350 L solution that contains 46 g of KCl? Step 2 Write the concentration expression. Step 3 Substitute solute and solution quantities into the expression and calculate. Solution

22. © 2013 Pearson Education, Inc. Chapter 8, Section 4 22 Summary of Concentration Expressions

23. © 2013 Pearson Education, Inc. Chapter 8, Section 4 23 Using Concentrations as Conversion Factors The value of 100 in the denominator of a percent expression is an exact number. Examples of conversion factors from concentrations are:

24. © 2013 Pearson Education, Inc. Chapter 8, Section 4 24 Write two conversion factors for each solution. 1. 8.50% (m/m) NaOH 2. 4.8% (m/v) HCl 3. 3.4 M NaOH Learning Check

25. © 2013 Pearson Education, Inc. Chapter 8, Section 4 25 1. 8.50% (m/m) NaOH 2. 4.8% (m/v) HCl 3. 3.4 M NaOH Solution

26. © 2013 Pearson Education, Inc. Chapter 8, Section 4 26 Guide to Using Concentration to Calculate Mass or Volume

27. © 2013 Pearson Education, Inc. Chapter 8, Section 4 27 How many grams of NaCl are needed to prepare 225 g of a 10.0% (m/m) NaCl solution? Learning Check

28. © 2013 Pearson Education, Inc. Chapter 8, Section 4 28 How many grams of NaCl are needed to prepare 225 g of a 10.0% (m/m) NaCl solution? Step 1 State the given and needed quantities. Analyze the Problem. Solution GivenNeed 225 g NaCl solution 10.0% (m/m) NaCl solution ? grams NaCl

29. © 2013 Pearson Education, Inc. Chapter 8, Section 4 29 How many grams of NaCl are needed to prepare 225 g of a 10.0% (m/m) NaCl solution? Step 2 Write a plan to calculate the mass or volume. g of solution % (m/m) factor g of NaCl Solution

30. © 2013 Pearson Education, Inc. Chapter 8, Section 4 30 Solution How many grams of NaCl are needed to prepare 225 g of a 10.0% (m/m) NaCl solution? Step 3 Write equalities and conversion factors. 10.0 g of NaCl = 100 g of NaCl solution Step 4 Set up the problem to calculate the mass or volume.

31. © 2013 Pearson Education, Inc. Chapter 8, Section 4 31 How many liters of a 2.00 M NaCl solution are needed to provide 67.3 g of NaCl? Learning Check

32. © 2013 Pearson Education, Inc. Chapter 8, Section 4 32 How many liters of a 2.00 M NaCl solution are needed to provide 67.3 g of NaCl? Step 1 State the given and needed quantities. Analyze the Problem. Solution GivenNeed 67.3 g NaCl 2.00 M NaCl solution ? liters NaCl solution

33. © 2013 Pearson Education, Inc. Chapter 8, Section 4 33 How many liters of a 2.00 M NaCl solution are needed to provide 67.3 g of NaCl? Step 2 Write a plan to calculate the mass or volume. g of NaCl molar moles molarity L of NaCl solution mass NaCl Solution

34. © 2013 Pearson Education, Inc. Chapter 8, Section 4 34 Solution How many liters of a 2.00 M NaCl solution are needed to provide 67.3 g of NaCl? Step 3 Write equalities and conversion factors. 1 mole of NaCl = 58.5 g of NaCl 2.00 mole of NaCl = 1 L of NaCl solution

35. © 2013 Pearson Education, Inc. Chapter 8, Section 4 35 Solution How many liters of a 2.00 M NaCl solution are needed to provide 67.3 g of NaCl? Step 4 Set up the problem to calculate the mass or volume.