1. Chemical Equation

2. Terminology in Chemical Equations
Chemical reactions – one or more chemical changes that occur at the same time, it maybe represented using equations which can be written in words or symbols
Reactants – pure substances that react in a chemical change
Products – pure substances formed in a chemical change that has different properties from those of the reactant

3. Terminology in Chemical Equations
Symbolic Equations – set of chemical symbols and formula that identify the reactants and products in a chemical reaction
Word equation – what we learned in 4.2!!
Coefficients – integers are placed in front of the formulas or a chemical symbol for an element. Is used to determine the ratio between various compounds in a chemical reaction
State of Matter – letters indicate the compounds’ states
(g) for gas
(l) for liquid
(s) for solid
(aq) for aqueous (dissolved in water)

4. Methane + oxygen carbon dioxide + water
REACTANTS PRODUCTS
Methane + oxygen carbon dioxide + water
Word equation

5. Law of Conservation of Mass
The law by a French chemist Antonie Lavisier
States that mass is conserved in a chemical reaction
The total mass of products is always EQUAL to the total mass of reactants in a chemical reaction

6. Balanced Equations
Shows the identities of each pure substance involved as well as the matching of number of atoms of each elements on both sides of chemical equations

8. Skeleton Equation

9. Try This 

10. Answers

11. Skeleton Equation

12. Balanced Equation 5 3 4 3 8 10 10

13. Hints for writing word equations from chemical equations
Nearly all elements that use chemical symbols that are not compounds are written as is ex. Cu for copper
Memorize Methane, Water, and Ammonia
Memorize the 7 diatomic elements which are all non-metals
Example: hydrogen + nitrogen ammonia
Skeleton equation: H2 + N2 NH3
Balanced equation: 3H2 + N2 2NH3

14. 7 Diatomic elements

15. Turn to “Strategies for Balancing Equations” on the second last page of chapter 4 notes
Read through hints for balancing equatinos on page 209 of textbook

16. Try This 

17. Answers

18. Answers