1. Chapter 11 Matter and Change 11.1 Describing Chemical Reactions
11.2 Types of Chemical Reactions
11.3 Reactions in Aqueous Solution

2. Write down 3 chemical reactions that you have seen or heard of.
Introduction to Chemical Equations
Do Now:
Write down 3 chemical reactions that you have seen or heard of.
What happens in a chemical reaction?

3. Introduction to Chemical Equations
Chemical Reaction
Atoms of one or more substances are rearranged to form different chemical compounds.

4. Signs of a Chemical Reaction Transfer of energy Change in color
Introduction to Chemical Equations
Signs of a Chemical Reaction
Transfer of energy
Change in color
Production of a gas
Formation of a precipitate

5. Iron + oxygen → iron(III) oxide
Introduction to Chemical Equations
Word Equations
Reactants → Products
Iron + oxygen → iron(III) oxide
Iron reacts with oxygen to produce iron(III) oxide (rust)

6. Symbols Used in Chemical Equations
Interpret Data
Symbols Used in Chemical Equations
Symbol
Explanation +
Separates two reactants or two products →
“Yields,” separates reactants from products
Use in place of → for reversible reactions
(s), (l), (g)
Designates a reactant or product in the solid state, liquid state, or gaseous state; placed after the formula
(aq)
Designates an aqueous solution; the substance is dissolved in water; placed after the formula
Indicates that heat is supplied to the reaction
A formula written above or below the yields sign indicates its use as a catalyst (in this example, platinum). Δ
heat Pt

7. Equations that show just formulas of the reactants and products.
Introduction to Chemical Equations
Skeleton Equations
Equations that show just formulas of the reactants and products.
Fe + O2 → Fe2O3

8. Coefficients are used to balance reactants and products.
Introduction to Chemical Equations
Balanced Equation
Coefficients are used to balance reactants and products.
4Fe + 3O2 → 2Fe2O3

9. Balancing Chemical Equations
Coefficients— small whole numbers put in front of formulas in an equation to balance it.
Add coefficients to balance the reactants and products. Do not add subscripts!

10. Balancing a Chemical Equation
Sample Problem 11.2
Balancing a Chemical Equation
AgNO3 + Cu → Cu(NO3)2 + Ag

11. Balancing a Chemical Equation
Sample Problem 11.2
Balancing a Chemical Equation
2AgNO3 + Cu → Cu(NO3)2 + 2Ag

12. Balancing a Chemical Equation
Sample Problem 11.3
Balancing a Chemical Equation
Aluminum is a good choice for outdoor furniture because it reacts with oxygen in the air to form a thin protective coat of aluminum oxide. Balance this equation.
Al + O2 → Al2O3

13. Balancing a Chemical Equation
Sample Problem 11.3
Balancing a Chemical Equation
Aluminum is a good choice for outdoor furniture because it reacts with oxygen in the air to form a thin protective coat of aluminum oxide. Balance this equation.
4Al + 3O2 → 2Al2O3

14. C3H8(g) + O2(g) → CO2(g) + H2O(l)
Balance the following equation.
C3H8(g) + O2(g) → CO2(g) + H2O(l)

15. C3H8(g) + 5O2(g) → 3CO2(g) + 4H2O(l)
Balance the following equation.
C3H8(g) + 5O2(g) → 3CO2(g) + 4H2O(l)

17. Law of Conservation of Mass Massproducts = Massreactants
Balancing Chemical Equations
Law of Conservation of Mass
Massproducts = Massreactants
Atoms are neither created nor destroyed in ordinary chemical reactions.

18. Molecules and Molecular Compounds
Remember HOFBrINCl molecules!
These elements are always found in nature in the form of diatomic molecules. Write them as such in your skeleton equations!
HOFBrINCl
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