1. Aqueous Reactions and Solution Stoichiometry
Chapter 4
Aqueous Reactions and Solution Stoichiometry

2. Properties of Aqueous Solutions
Solutions are homogeneous mixtures of 2 or more substances

3. Properties of Aqueous Solutions
Aqueous Solutions are solutions in which water is the dissolving medium

4. Properties of Aqueous Solutions
A solvent is the substance that is present in larger quantities.

5. Properties of Aqueous Solutions
A solute is the substance being dissolved into the solvent.

6. Properties of Aqueous Solutions
Electrolytes conduct electricity.

7. Properties of Aqueous Solutions
Aqueous solutions made of ionic compounds are electrolytes due to the presence of ions.

8. Properties of Aqueous Solutions
An aqueous solution of a molecular compound is called a nonelectrolyte

9. Properties of Aqueous Solutions
Strong electrolytes exist in solution completely as ions (soluble ionic compounds)

10. Properties of Aqueous Solutions
Weak electrolytes exist mostly as molecules

11. Properties of Aqueous Solutions
Nonelectrolytes exist only as molecules

12. Properties of Aqueous Solutions
Figure 04-03
Title:
Dissolution in water.
Caption:
(a) When an ionic compound dissolves in water, H2O molecules separate, surround, and disperse the ions into the liquid. (b) Methanol, CH3OH, a molecular compound, dissolves without forming ions. The methanol molecules contain black spheres, which represent carbon atoms. In both parts (a) and (b) the water molecules have been moved apart so that the solute particles can be seen more clearly.
Notes:
Keywords:

13. 4.1

14. Precipitation Reactions
Precipitation reactions are those that result in the formation of an insoluble product

15. Precipitation Reactions

16. Precipitation Reactions
Precipitation reactions occur when certain pairs of oppositely charged ions attract to each other so strongly that they form an insoluble ionic solid

17. Precipitation Reactions
Solubility of a substance is the amount of that substance that can be dissolved in a given quantity of solvent

18. Precipitation Reactions
Any substance with a solubility less than 0.01mol/L will be referred to as insoluble

19. Precipitation Reactions
The solubility guidelines for common ionic compounds in water is organized by anions

20. Precipitation Reactions

21. 4.2

22. Precipitation Reactions
To predict whether a precipitate will form when we mix aqueous solutions of electrolytes …

23. Precipitation Reactions
(1)note the ions present in the reactants
(2) consider combinations of anions and cations
(3) use the table to predict if any of the combinations are insoluble

24. Precipitation Reactions
Will a precipitate form when Mg(NO3)2 and NaOH are mixed?

25. Precipitation Reactions
This is called a double replacement reaction.
AX + BY  AY + BX

26. Practice 4.3

27. Precipitation Reactions
A molecular equation shows the complete chemical formulas of the reactants and the products

28. Precipitation Reactions
A complete ionic equation shows all strong electrolytes as ions rather than as compounds

29. Precipitation Reactions
Spectator ions are ions that appear as identical forms on both sides of the equation; they are present but don’t play a direct role in the reaction

30. Precipitation Reactions
Net ionic equations do not show spectator ions

31. Writing Net Ionic Equations
Write a balanced mol. E.q
Rewrite to show ions that form in solution
Cancel spectator ions

32. 4.4

33. Acids produce H+ when dissolved in water Acids are proton donors
Acid-Base Reactions
Acids produce H+ when dissolved in water
Acids are proton donors

34. Bases produce OH- when they dissolve in water
Acid-Base Reactions
Bases accept H+ions
Bases produce OH- when they dissolve in water

35. Strong acids and bases are strong electrolytes – ionize completely
Acid-Base Reactions
Strong acids and bases are strong electrolytes – ionize completely

36. Acid-Base Reactions
Weak acids and bases are weak electrolytes – partially ionize ( do not write in ionized form)

37. List Strong Acids and Bases
Acid-Base Reactions
List Strong Acids and Bases

38. Figure 04-T02
Title:
Table 4.2
Caption:
Common Strong Acids and Bases
Notes:
Keywords:

39. 4.5 Figure 04-T02 Title: Table 4.2 Caption:
Common Strong Acids and Bases
Notes:
Keywords:

40. Identifying Strong, Weak, and Non Electrolytes Chart
Ionic
Soluble
N/A
Insoluble
Molecular
Strong Acids
Weak Acids Weak Bases (NH3)
All other compounds

41. Classifying SE, WE, or NE
1. Is it ionic or molecular?
2. If ionic – is it soluble?
3. If molecular – is it an acid?
4. If an acid – strong or weak?
5. Is it weak base NH3?
6. Everything else is a non electrolyte

42. 4.6

43. Acid-Base Reactions
A neutralization reaction occurs when an acid and base are mixed producing water and salt
Salt means any ionic compound whose cation comes from the base and anion from the acid

44. Aq. solutions of hydrobromic acid and sodium hydroxide mix
Acid-Base Reactions
Example:
Aq. solutions of hydrobromic acid and sodium hydroxide mix

45. Acid-Base Reactions
Aq. hydrochloric acid reacts with solid magnesium hydroxide.

46. Acid-Base Reactions
Reactions with the S2- ion or CO32- ion with acids will form gases with low solubility in water

47. Acid-Base Reactions
Aq. HCl
reacts with
Baking soda

48. Aq. Hydrochloric acid reacts with sodium sulfide
Acid-Base Reactions
Aq. Hydrochloric acid reacts with sodium sulfide

49. 4.7

50. Oxidation Numbers
Oxidation numbers of an atom in a substance is a hypothetical charge based on a set of rules.
1. For an atom in its elemental form the oxidation number is always zero
2. For any monatomic ion the oxidation number equals the charge on the ion

51. Oxidation Numbers
3. Nonmetals usually have negative oxidation numbers.
a. O is –2 except in peroxides where O22-
giving each O –1.
b. H is +1 with nonmetals and –1 with
metals .
c. F is –1 in all compounds. Other halogens have –1
except when combined with oxygen they have
positive oxidation states.

52. Oxidation Numbers
4. The sum of oxidation numbers of all atoms in a neutral compound is 0.
The sum of oxidation numbers in a polyatomic ion is equal to the charge of the ion.

53. 4.8

54. Oxidation-Reduction Reactions
Reactions where electrons are transferred between reactants

55. Oxidation-Reduction Reactions
Oxidized – when an atom, ion, or molecule becomes more positively charged (lost e-)
Reducing Agent = the substance that is oxidized

56. Oxidation-Reduction Reactions
Reduced – when an atom, ion, or molecule has become more negative (gain e-)
Oxidizing agent = the substance that is reduced

57. What does Leo the Lion say?

58. LEO says GER

59. Oxidation-Reduction Reactions
Determine oxidation numbers, then identify the oxidizing agent and reducing agent in the rxn below.
Figure 04-12
Title:
Oxidation of calcium metal by molecular oxygen.
Caption:
The oxidation involves transfer of electrons from the metal to O2, eventually leading to formation of CaO.
Notes:
Keywords:

60. Oxidation-Reduction Reactions
A single replacement rxn is when an ion in solution is replaced through oxidation of an element

61. Oxidation-Reduction Reactions

62. Oxidation-Reduction Reactions

63. 4.9

64. Oxidation-Reduction Reactions
Activity series is a list of metals arranged in order of decreasing ease of oxidation
Any metal on the list can be oxidized by the ions of elements below it.

66. 4.10

67. Concentration of Solutions

68. Concentration of Solutions
Molarity (M)
= moles of solute / L soln

69. 4.11

70. Making a Solution: How do you make a 250.0mL soln of 0.1M CuSO4?
Figure 04-16
Title:
Procedure for preparation of L of 1.00 M solution of CuSO4.
Caption:
(a) Weigh out mol (39.9 g) of CuSO4 (formula weight = amu). (b) Put the CuSO4 (solute) into a 250-mL volumetric flask, and add a small quantity of water. (c) Dissolve the solute by swirling the flask. (d) Add more water until the solution just reaches the calibration mark etched on the neck of the flask. Shake the stoppered flask to ensure complete mixing.
Notes:
Keywords:

71. Concentration of Solutions
Electrolytes and Concentration:
When an ionic compound dissolves, the relative concentration of ion depends on the chemical formula

72. 4.12

73. Concentration of Solutions
A dilution can be made to concentrated stock solutions by adding water to the solutions, and therefore making them less concentrated.
M1V1 = M2V2

74. 4.14

75. Solution Stoichiometry
Use mole conversions (molarity, molar mass, etc.) and mole ratios to solve stoichiometry problems through DA

76. Solution Stoichiometry

78. Putting it all together
A sample of 70.5 mg of potassium phosphate is added to 15.0 mL of M silver nitrate.
(a) Write the molecular equation for the reaction.
(b) What is the limiting reactant in the reaction?
(c) Calculate the theoretical yield, in grams, of the precipitate that forms.

79. Putting it all together
A solution of 100.0mL of 0.200M KOH is mixed with a solution of 200.0mL of 0.150M NiSO4.
(a) Write the molecular equation for the reaction.
(b) What is the limiting reactant in the reaction?
(c) Calculate the theoretical yield, in grams, of the precipitate that forms.
(d) What is the molarity of each ion that remains in the solution.