1. Chapter 9
Chemical Reactions

2. National Standards for Chapter 9
UCP.3 – Change, constancy, and measurement
UCP.5 – Form and function
A.1 –Abilities necessary to do scientific inquiry
A.2 – Understandings about scientific inquiry
B-2 – Structure and properties of matter
B-3 – Chemical reactions
B-6 – Interactions of energy and matter

3. Vocabulary/Study Guide
Define each term using the Glossary
Either write on the handout, or use your own paper
This is due on Test Day (tentatively, Thursday, March 6)

4. Section 1: Reactions and Equations
National Standards:
UCP.3 – Change, constancy, and measurement
UCP.5 – Form and function
A.1 –Abilities necessary to do scientific inquiry
B-2 – Structure and properties of matter
B-3 – Chemical reactions
B-6 – Interactions of energy and matter

5. Objectives – Section 1 Recognize evidence of chemical change.
Represent chemical reactions with equations.
Balance chemical equations.
REVIEW VOCABULARY:
chemical change: a process involving one or more substances changing into a new substance

6. New Vocabulary
chemical reaction reactant product chemical equation coefficient Chemical reactions are represented by balanced chemical equations.

7. Launch Lab
Title: How do you know when a chemical change has occurred? (page 280)

8. Math Skills Transparency 11

9. Chemical Reactions
The process by which one or more substances are rearranged to form different substances is called a chemical reaction.

10. Chemical Reactions
Evidence that a chemical reaction may have occurred:
Change in temperature
Change in color
Odor
Gas bubbles
Appearance of a solid (precipitate)

11. Representing Chemical Reactions
Chemists use statements called equations to represent chemical reactions.
Reactants are the starting substances.
Products are the substances formed in the reaction.
This table summarizes the symbols used in chemical equations.

12. Representing Chemical Reactions
In word equations, aluminum(s) + bromine(l) → aluminum bromide(s) reads as “aluminum and bromine react to produce aluminum bromide”.
Skeleton equations use symbols and formulas to represent the reactants and products. Al(s) + Br(l) → AlBr3(s)
Both word and skeleton equations lack information about how many atoms are involved in the reaction.

13. Representing Chemical Reactions
A chemical equation is a statement that uses chemical formulas to show the identities and relative amounts of the substances involved in a chemical reaction.

14. Representing Chemical Reactions
Practice Problems #1-3, page 284

15. Balancing Chemical Equations
This figure shows the balanced equation for the reaction between aluminum and bromine.

16. Balancing Chemical Equations
A coefficient in a chemical equation is the number written in front of a reactant or product, describing the lowest whole-number ratio of the amounts of all the reactants and products.

17. Balancing Chemical Equations

18. Balancing Chemical Equations

19. Balancing Chemical Equations

20. Transparency 29: Parts of a Balanced Chemical Equation

21. Representing Chemical Reactions
Practice Problems #4-6, page 287

22. Transparency 30: Balancing Chemical Equations

23. Balancing Chemical Equations
The most fundamental law in chemistry is the law of conservation of mass.
Balanced equations show this law.

24. Balancing Chemical Equations

25. Homework, Section 1 SECTION 1 REVIEW, Page 288 Questions #7-13
Answer with complete sentences
Due tomorrow

26. Section 2: Classifying Chemical Reactions
National Standards:
UCP.3 – Change, constancy, and measurement
UCP.5 – Form and function
A.1 –Abilities necessary to do scientific inquiry
B-2 – Structure and properties of matter
B-3 – Chemical reactions

27. Objectives – Section 2 Classify chemical reactions.
Identify the characteristics of different classes of chemical reactions.
Review Vocabulary:
metal: an element that is a solid at room temperature, a good conductor of heat and electricity, and is generally shiny

28. New Vocabulary
synthesis reaction combustion reaction decomposition reaction single-replacement reaction double-replacement reaction precipitate There are four types of chemical reactions: synthesis, combustion, decomposition, and replacement reactions.

29. Types of Chemical Reactions
Chemists classify reactions in order to organize the many types.

30. Synthesis Reactions
A synthesis reaction is a reaction in which two or more substances react to produce a single product.
When two elements react, the reaction is always a synthesis reaction.

31. Combustion Reactions
In a combustion reaction, oxygen combines with a substance and releases energy in the form of heat and light.
Heated hydrogen reacts with oxygen to produce heat and water in a combustion reaction. This is also a synthesis reaction.

32. Combustion Reactions
Practice Problems #14-17, page 291

33. Decomposition Reactions
A decomposition reaction is one in which a single compound breaks down into two or more elements or new compounds.
Decomposition reactions often require an energy source, such as heat, light, or electricity, to occur.

34. Decomposition Reactions
Practice Problems #18-20, page 292

35. Replacement Reactions
A reaction in which the atoms of one element replace the atoms of another element in a compound is called a single replacement reaction.
A + BX → AX + B

36. Replacement Reactions
A metal will not always replace a metal in a compound dissolved in water because of differing reactivities.
An activity series can be used to predict if reactions will occur.

37. Replacement Reactions
Halogens frequently replace other halogens in replacement reactions.
Halogens also have different reactivities and do not always replace each other.

38. Transparency 31: The Activity Series

39. Replacement Reactions
Title: Analyze Trends, page 294

40. Replacement Reactions
Practice Problems #21-24, page 295

41. Replacement Reactions
Double replacement reactions occur when ions exchange between two compounds.
This figure shows a generic double replacement equation.

42. Replacement Reactions
The solid product produced during a chemical reaction in a solution is called a precipitate.
All double replacement reactions produce either water, a precipitate, or a gas.

43. Replacement Reactions
This table shows the steps to write double replacement reactions.

44. Replacement Reactions
Practice Problems #25-28, page 297

45. Replacement Reactions
This table summarizes different ways to predict the products of a chemical reaction.

46. Transparency 32: Summary of Reaction Types

47. Lab: Develop an Activity Series, page 310

48. Lab: Single-Replacement Reactions

49. Lab: Double-Replacement Reactions

50. Homework, Section 2 SECTION 2 REVIEW, Page 298 Questions #29-34
Answer with complete sentences
Due tomorrow

51. Section 3: Reactions in Aqueous Solutions
National Standards:
UCP.3 – Change, constancy, and measurement
UCP.5 – Form and function
A.1 –Abilities necessary to do scientific inquiry
A.2 – Understandings about scientific inquiry
B-2 – Structure and properties of matter
B-3 – Chemical reactions
B-6 – Interactions of energy and matter

52. Objectives – Section 3 Describe aqueous solutions.
Write complete ionic and net ionic equations for chemical reactions in aqueous solutions.
Predict whether reactions in aqueous solutions will produce a precipitate, water, or a gas.
Review Vocabulary:
solution: a uniform mixture that might contain solids, liquids, or gases

53. New Vocabulary
aqueous solution solute solvent complete ionic equation spectator ion net ionic equation Double-replacement reactions occur between substances in aqueous solutions and produce precipitates, water, or gases.

54. Aqueous Solutions
An aqueous solution contains one or more dissolved substances (called solutes) in water.
The solvent is the most plentiful substance in a solution.

55. Aqueous Solutions Water is always the solvent in an aqueous solution.
There are many possible solutes—sugar and alcohol are molecular compounds that exist as molecules in aqueous solutions.
Compounds that produce hydrogen ions in aqueous solutions are acids.

56. Aqueous Solutions
Ionic compounds can also be solutes in aqueous solutions.
When ionic compounds dissolve in water, their ions separate in a process called dissociation.

57. Type of Reactions in Aqueous Solutions
When two solutions that contain ions as solutes are combined, the ions might react.
If they react, it is always a double replacement reaction.
Three products can form: precipitates, water, or gases.

58. Type of Reactions in Aqueous Solutions
Title: Observe a Precipitate-Forming Reaction, page 301

59. Type of Reactions in Aqueous Solutions
Aqueous solutions of sodium hydroxide and copper(II) chloride react to form the precipitate copper(II) hydroxide.
2NaOH(aq) + CuCl2(aq) → 2NaCl(aq) + Cu(OH)2(s)
Ionic equations that show all of the particles in a solution as they actually exist are called complete ionic equations.
2Na+(aq) + 2OH–(aq) + Cu2+ (aq)+ 2Cl–(aq) → 2Na+(aq) + 2Cl–(aq) + Cu(OH)2(s)

60. Type of Reactions in Aqueous Solutions
Ions that do not participate in a reaction are called spectator ions and are not usually written in ionic equations.
Formulas that include only the particles that participate in reactions are called net ionic equations.
2OH–(aq) + Cu2+(aq) → Cu(OH)2(s)

61. Type of Reactions in Aqueous Solutions
Practice Problems #35-39, page 302

62. Type of Reactions in Aqueous Solutions
Some reactions produce more water molecules.
No evidence of a chemical reaction is observable.
HBr(aq) + NaOH(aq) → H2O(l) + NaBr(aq)
Without spectator ions H+(aq) + OH–(aq) → H2O(l).

63. Type of Reactions in Aqueous Solutions
Practice Problems #40-44, page 304

64. Type of Reactions in Aqueous Solutions
Gases that are commonly produced are carbon dioxide, hydrogen cyanide, and hydrogen sulfide.
2HI(aq) + Li2S(aq) → H2S(g) + 2LiI(aq)

65. Type of Reactions in Aqueous Solutions
Another example is mixing vinegar and baking soda, which produces carbon dioxide gas.
HCl(aq) + NaHCO3(aq) → H2CO3(aq) + NaCl(aq)
H2CO3(aq) decomposes immediately.
H2CO3(aq) → H2O(l) + CO2(g)

66. Type of Reactions in Aqueous Solutions
Practice Problems #45-49, page 306

67. Type of Reactions in Aqueous Solutions
Two reactions can be combined and represented by a single chemical reaction.

68. Type of Reactions in Aqueous Solutions
Reaction 1 HCl(aq) + NaHCO3(aq) → H2CO3(aq) + NaCl(aq) Reaction 2 H2CO3(aq) → H2O(l) + CO2(g) Combined equation HCl(aq) + NaHCO3(aq) + H2CO3(aq) → H2CO3(aq) + NaCl(aq) + H2O(l) + CO2(g) Overall equation HCl(aq) + NaHCO3(aq) → H2O(l) + CO2(g) + NaCl(aq)

69. Transparency 33: Types of Equations

70. Math Skills Transparency 12: Simplifying Equations

71. Homework, Section 3 SECTION 3 REVIEW, Page 308 Questions #50-56
Answer with complete sentences
Due tomorrow

72. Reactions and Equations
SECTION9.1
Reactions and Equations
Study Guide
Key Concepts
Some physical changes are evidence that indicate a chemical reaction has occurred.
Word equations and skeleton equations provide important information about a chemical reaction.
A chemical equation gives the identities and relative amounts of the reactants and products that are involved in a chemical reaction.
Balancing an equation involves adjusting the coefficients until the number of atoms of each element is equal on both sides of the equation.

73. Classifying Chemical Reactions
SECTION9.2
Classifying Chemical Reactions
Study Guide
Key Concepts
Classifying chemical reactions makes them easier to understand, remember, and recognize.
Activity series of metals and halogens can be used to predict if single-replacement reactions will occur.

74. Reactions in Aqueous Solutions
SECTION9.3
Reactions in Aqueous Solutions
Study Guide
Key Concepts
In aqueous solutions, the solvent is always water. There are many possible solutes.
Many molecular compounds form ions when they dissolve in water. When some ionic compounds dissolve in water, their ions separate.
When two aqueous solutions that contain ions as solutes are combined, the ions might react with one another. The solvent molecules do not usually react.
Reactions that occur in aqueous solutions are double-replacement reactions.