1. Types of Chemical Reactions p.261 - 284
Chapter 8 Notes
Types of Chemical Reactions p

2. 8.1 Chemical Reactions (p.261-269)
Starting on p.261 at the top, find the definitions for the following:
Chemical reaction, Reactant, Product
Chemical reactions are written like this: Reactant Product
p. 261, write the 4 indications of a chemical reaction (only the italicized section)
p.262, write the 3 characteristics of a chemical equation (only the italicized section)
p. 263, copy down Table 1 (7 diatomic molecules)
What is the difference between a word equation and a formula equation?
How does the law of conservation of mass apply to chemical reactions?
What does the term yield mean in the context of chemical reactions?
p.266, Copy down the following 7 symbols from the chart
Yields, reversible reaction, (s), (l), (aq), (g), and heated
p.269, copy down the italicized portion of number 2.

3. 8.1 section review
Complete questions 1 - 3

4. 8.2 Types of Chemical Reactions
Synthesis (or Composition) reactions
Decomposition reactions
Single-displacement reactions
Double-displacement reactions
Acid/Base reactions: Acid + Base  salt + water
Combustion reactions

5. 1. Synthesis Reactions aka: composition or addition
What happens: two or more substances combine to form a new compound
General Equation: A+X  AX
Example: Zn + O  ZnO
Specific examples – p Synthesis Reactions with Oxides

6. 2. Decomposition Reactions
What Happens: a compound is broken down in a reaction which makes two or more simpler compounds
Key words to indicate decomposition:
Electrolysis, heated,
General Equation: AXA+X
Example: CaCO3  CaO + CO2
Specific examples – p.280 Metal Carbonates, Metal Hydroxides, and Metal Chlorates

7. 3. Single-Displacement Reactions
AKA: Single-replacement
What happens: one element replaces a similar element in a compound
General equation: AX+B BX + A
Example: Zn + 2 HCl  ZnCl2 + H2
According to the activity series, only a more reactive metal or nonmetal will replace a cation or anion in a compound.
There are several versions of an activity series, we will use the one on p.286 in your textbook.
Practice p.287 #1-3, then section review #2-3 on your own.

8. 4. Double-Displacement reactions
AKA: double-replacement
What Happens: ions from two compounds change places to produce two new compounds
General Eq: AX + BY  AY + BX
Ex: HCl + NaOH  H2O + NaCl
Formation of a precipitate p.282
Formation of water in acid/base reactions.

9. 5. Combustion Reactions aka: burning
What Happens: reaction of oxygen gas (O2), which releases heat and light
Production of water p.283
General: CXHY + O2  H2O + CO2
Example: CH4 + 2 O2  CO2 + 2 H2O

10. How can you tell which type of reaction?
Composition: 2 elements (only 1 product)
Decomposition: 1 reactant (2+ products)
Single-displacement: 1 element and 1 compound
Double-displacement: 2 compounds
Combustion: CXHY and O2

11. Balancing Chemical Equations (8.1)
What is a Balanced Equation?
same number of each type of atom on both sides of the equation
This equation is NOT balanced:
N2 + H2  NH3
N = 2 N = 1
H = 2 H = 3
This equation IS balanced:
N2 + 3 H2  2 NH3
N = 2 N = 2
H = 6 H = 6

12. Steps to balance an equation:
Write the chemical reaction:
Mg + O2  MgO
Count how many of each type of atom are on the reactant side and the product side
Mg = 1 Mg = 1
O = O = 1

13. Steps to balance an equation:
Add coefficients to balance the equation
Remember, you can only add coefficients, you can’t change subscripts!
2 Mg + O2  2 MgO
Mg = 1x2= 2 Mg = 1x2= 2
O = 2 O = 1x2= 2

14. Polyatomic Ions H2SO4 + Mg  MgSO4 + H2
H = 2 H = 2
SO4 = 1 SO4 = 1
Mg = 1 Mg = 1
Note: polyatomic ions are a single item in your inventory – DO NOT separate them into individual elements

15. Practice Na + Br2  NaBr Al(NO3)3 + Li LiNO3 + Al
C3H O2 CO2 + H2O

16. Summing it up
Practice p.272 (#1ab, 2)
Practice p.274 (#1abc)

17. Predicting Products of Reactions
Step 1: Identify reaction type
Step 2: Label cations and anions on the reactant side.
Step 3: Determine how cations and anions will recombine on the product side.
Step 4: Consult activity series to determine if reaction will occur.
Step 5:Cross charges on any compounds and determine if anything is diatomic.

18. Reactants Type of Reaction Products
CxHy + O2
Combustion
Always the same: CO2 + H2O
A + X 
Synthesis
Combine the reactants into one formula: AX
AX 
Decomposition
Break into smaller pieces: A+X
AX + B 
Single-Displacement
Is displaced ion positive or negative? Write lone ion plus new compound: A + BX
AX + BY 
Double-Displacement
Join positive ion from one compound with negative ion from the second compound, and vice versa: AY + BX

19. Examples
Ex1: Na + Cl _______
Ex2: H2 + O2

20. Examples
Ex1: MgBr2 ______ + ______
Ex2: CaCO3 ______ + ______

21. Examples
Ex1: Li + SrO ______ + ______
Ex2: KOH + Ba ______ + ______

22. Examples
Ex1: AgNO3 + BeCl2
Ex2: FePO4 + ZnS

23. Examples
Ex1: C2H6 + O CO2 + H2O
Ex2: C6H12O6 + O2

24. 8.2 section review p. 284 (1-4)

25. Activity Series of the Elements
Section 8.3
Pages

26. Activity Series
An activity series organizes elements by how easily they react, or how active they are in a chemical reaction.
Metals: easier loss of electrons
Nonmetals: easier gain of electrons
ONLY MATTERS IN SINGLE and DOUBLE DISPLACEMENT!

27. Rules
There is only one rule – an element will replace (or displace) another element only if the second element is below it on the chart.
Ex: Lithium is at the top of the chart, so it will displace any metal in a compound that it is reacting with.
Complete the activity series worksheet (front side only)

28. Solubility in chemical reactions
How does one know what state of matter a compound is in? How does one know if a precipitate is formed or not?
Use the solubility guidelines chart to determine if a compound is soluble (aqueous, or dissolved in solution) or insoluble (solid, or forms a precipitate)
Complete the worksheet on the back

29. Homework
Complete both sides of the worksheet titled “Double Displacement Reactions”.
Use your activity series and solubility chart to determine: if a reaction will occur and if any precipitates are formed.
If the reaction will occur, write the products formed. If not, write no reaction.