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
Work with your table mates to come up with a list of 5 chemical reactions that you have seen or heard of.

3. 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

4. Chemical Equations Reactants → Products
Introduction to Chemical Equations
Chemical Equations
Reactants → Products
Reactants on the left, products on the right.
An arrow separates them.
You read the arrow as yields, gives, or reacts to produce.

5. 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

6. Word Equation: Iron + oxygen → iron(III) oxide
Introduction to Chemical Equations
Rusting of Iron
Word Equation: Iron + oxygen → iron(III) oxide
Skeleton Equation: Fe + O2 → Fe2O3
Balanced Equation: 4Fe + 3O2 → 2Fe2O3

7. 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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8. 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.

9. What does that mean for you?
Balancing Chemical Equations
What does that mean for you?
The same number of atoms of each element must be present on both sides of the equation.

10. 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!

11. Carbon burns in the presence of oxygen to produce carbon dioxide.
Balancing Chemical Equations
Carbon burns in the presence of oxygen to produce carbon dioxide.

12. Carbon burns in the presence of oxygen to produce carbon dioxide.
Balancing Chemical Equations
Carbon burns in the presence of oxygen to produce carbon dioxide.
C(s) Carbon +
O2(g) Oxygen
CO2(g) Carbon dioxide

13. Carbon burns in the presence of oxygen to produce carbon dioxide.
Balancing Chemical Equations
Carbon burns in the presence of oxygen to produce carbon dioxide.
C(s) Carbon +
O2(g) Oxygen
CO2(g) Carbon dioxide
Reactants 1 carbon atom, 2 oxygen atoms
Product 1 carbon atom, 2 oxygen atoms
This equation is balanced.
You do not need to change the coefficients.
They are all understood to be 1.

14. When hydrogen and oxygen are mixed, the product is water.
Balancing Chemical Equations
When hydrogen and oxygen are mixed, the product is water.

15. When hydrogen and oxygen are mixed, the product is water.
Balancing Chemical Equations
When hydrogen and oxygen are mixed, the product is water.

16. When hydrogen and oxygen are mixed, the product is water.
Balancing Chemical Equations
When hydrogen and oxygen are mixed, the product is water.

17. When hydrogen and oxygen are mixed, the product is water.
Balancing Chemical Equations
When hydrogen and oxygen are mixed, the product is water.
To correct this equation, put the coefficient 2 in front of H2.
The equation is now balanced.

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

19. 2AgNO3(aq) + Cu(s) → Cu(NO3)2(aq) + 2Ag(s)
Sample Problem 11.2
2AgNO3(aq) + Cu(s) → Cu(NO3)2(aq) + 2Ag(s)

20. 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 the equation for this reaction.
Al(s) + O2(s) → Al2O3(s)

21. Sample Problem 11.3
4Al(s) + 3O2(s) → 2Al2O3(s)

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

23. 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)

25. END OF 11.1