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

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

3. How do you know if a chemical reaction is taking place?
Introduction to Chemical Equations
How do you know if a chemical reaction is taking place?

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. Introduction to Chemical Equations
Reactants → Products

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

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

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

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

10. Law of Conservation of Mass
Balancing Chemical Equations
Law of Conservation of Mass
During any chemical reaction, the mass of the products always equals the mass of the reactants.
Atoms are neither created nor destroyed in ordinary chemical reactions.
The same number of atoms of each element must be present on both sides of the equation.

11. 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

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

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

15. 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

16. 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

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

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

20. END OF 11.1