1. Unit V: The Mole Concept
V.6. Molar Concentrations

2. Solution A Homogeneous mixture
A mixture that looks like a pure substance.
Particles of all substances are completely mixed together

3. Solutions: Homogenous Mixtures
A solute is the substance to be dissolved (*component present in smaller amounts)
The solvent is the one doing the dissolving (*component present in larger amounts)
Universal solvent- generally thought of as water

4. Concentration
The CONCENTRATION of a substance in solution is the amount of the substance which exists in a given volume of solution
In Simple Terms

5. Concentration More Terms
Concentrated solution – there is a large amount of substance dissolved in the solution
A Dilute solution – there is very little substance dissolved in the solution

6. Concentration
Units of Concentration:

7. Molar Concentration Molarity
Unit mainly used in chemistry
Molarity is the number of moles of the substance contained in 1L of solution

8. Molarity
mol
M L

9. Molarity
mol
M L

10. Molarity
If we can calculate moles then we can determine grams using our Mole Diagram
mol
M L
grams

11. CHEM LINGO [ Square Brackets ] = Molarity or Molar Concentration
[NaOH]

12. Example 1
Austin dissolves 40.0 g of NaOH in enough water to make a mL solution. What is the molar concentration of NaOH?
[NaOH] = ? M
Plan grams  moles  Molarity

13. Example 1
Austin dissolves 40.0 g of NaOH in enough water to make a mL solution. What is the molar concentration of NaOH?
[NaOH] = ? M
Plan grams  moles  Molarity

14. Example 2
Angela wants to make a mL of M CaCl2. What mass of solid CaCl2 should she start with?
Plan: M x L  mol g

15. Example 2
Angela wants to make a mL of M CaCl2. What mass of solid CaCl2 should she start with?
Plan: M x L  mol g

16. Example 3
Chris wants to evaporate some 3.0M NaCl to obtain g of NaCl. What volume of solution should she evaporate?
g  mol  L

17. Example 3
Chris wants to evaporate some 3.0M NaCl to obtain g of NaCl. What volume of solution should he evaporate?
g  mol  L

18. Example 4
Elyse has 4.0 g of NaOH and she wants to make a 0.80 M solution. She should add water to a total volume of what?
Plan: g  mol  L

19. Example 4
Elyse has 4.0 g of NaOH and she wants to make a 0.80 M solution. She should add water to a total volume of what?
Plan: g  mol  L

20. Experimental Procedure
Give directions in a step wise manner
Rough outline of experimental procedure
Typically want you to figure out the mass or volume required to make a certain solution

21. Experiment Procedure Example 1
Blair needs to make mL of 0.25 M NaOH. Describe the procedure Blair needs to follow in order to make this solution.
Plan: M x L  mol  g

22. Experiment Procedure Example 1
Blair needs to make mL of 0.25 M NaOH. Describe the procedure Blair needs to follow in order to make this solution.
Plan: M x L  mol  g

23. Experiment Procedure Example 1
Blair needs to make mL of 0.25 M NaOH. Describe the procedure Blair needs to follow in order to make this solution.
Plan: M x L  mol  g

24. Experimental Procedure Example 2
Mark is asked to give directions to make mL of 0.55M K2SO4. What should he say?
M x L  mol  g

25. Experimental Procedure Example 2
Mark is asked to give directions to make mL of 0.55M K2SO4. What should he say?
M x L  mol  g

26. Experimental Procedure Example 2
Mark is asked to give directions to make mL of 0.55M K2SO4. What should he say?
M x L  mol  g

27. Experimental Procedure Example 3
Tianna needs to tell Savannah how to make a 2.00L solution of 6.0 M NaOH.
Plan: M x L  mol  g

28. Experimental Procedure Example 3
Tianna needs to tell Savannah how to make a 2.00L solution of 6.0 M NaOH.
Plan: M x L  mol  g

29. Experimental Procedure Example 3
Tianna needs to tell Savannah how to make a 2.00L solution of 6.0 M NaOH.
Plan: M x L  mol  g

30. Hebden
Do Exercises 59(b, d, e & f), 60 (c & e), 62 and 64 on pages 98 of Hebden

31. Dilutions of Solution
Concentration and Volume are inversely related

32. Dilutions of Solution When we add water the volume increases
Volume ↑ Concentration ↓
When we remove water the volume decreases
Volume ↓ Concentration ↑

33. Dilutions of Solutions
For the same solution
If we double the volume  the concentration is halved (x ½)
If we triple the volume  the concentration x 1/3

34. Dilutions of Solutions
Volume
Concentration
C x V

35. Concentration 50.0 mL of 6.0 M HCl 100.00 mL of 0.30 M HCl
Add 50.0 mL of water

36. FIND BEAKER

37. Concentration

38. Dilution Formula
I = Initial
F = Final
V = Volume
C = Concentration

39. Dilution Formula

40. Example
Matt adds mL of water to 50.0 mL of 0.60 M solution of HCl. Find the final [HCl] .

41. Example 2
Connor adds water to mL of 0.25 M HF to a volume of mL Find the final [HF].

42. Example 3*
Tanner dilutes 60.0 mL of 0.40 M HNO3 to 0.15 M. What is the final volume?

43. Example 3*
Tanner dilutes 60.0 mL of 0.40 M HNO3 to 0.15 M. How much water did Tanner add?

44. Diluting Stock Solutions
Stock solutions – are concentrated solutions from the suppliers

45. Diluting Stock Solutions
12 M HCl
15 M HNO3
18 M H2SO4

46. Example 4
Natasha wants to make mL of 0.20 M HCl. What volume of 12.0 M HCl should she start with?

47. Example 4
Natasha is unfamiliar with the ways of chemistry. Explain how she should proceed to make her solution from the concentrated stock solution.

48. Hebden Do Exercises 78, 82, 89, 91 on pages 102-103 of Hebden
Do Hand-In Assignment #10

49. DONE WITH THE MOLE

50. Unit Test % mass and % composition
Mass of element when given a mass of a compound
Empirical and Molecular Formulas
Concentration: Solution, Solvent, Solute
Molar concentration/ Molarity
Dilutions of Solutions