1. C2.3 describing chemical reactions
A chemical reaction is a process in which substances interact, causing the formation of new substances with new properties.
Chemists use equations to describe chemical reactions. There are two kinds of equations
Word equations: Names of chemicals are written out in full
Chemical equations: chemical formulas are used to represent chemicals
During a chemical reaction, reactant particles collide, allowing their atoms (or ions) to rearrange and form products.
Reactants are the substances that are used up during the reaction
Products are the substances that are produced during the reaction.
Reactants
Yields
Products
Word equation
Iron + sulfur 
Iron (II) sulfide + energy
Chemical equation
Fe + S
FeS + energy

2. C2.3 describing chemical reactions
Chemical equations give far more detail that word equations
They give the chemical formula of the reactants and products as well as their state
Example
Zinc + copper sulfate  zinc sulfate + copper + energy
Zn(s) + CuSO4 (aq)  ZnSO4 (aq) + Cu(s) + energy

3. C3.2 The law of conservation of mass and atomic theory
Law of conservation of mass: the statement that, in any given chemical reaction, the total mass of the reactants equals the total mass of the products.
Atoms cannot be created or destroyed, they are just rearranged to form products
All chemical equations must obey the law of conservation of mass
Read through explanation on p. 230 as a class (to show how coefficients are added)

4. C3.4 Balancing chemical equations: Activity
Balance 7 of the 14 skeleton equations that are found on page 236 #7.

5. C3.5 Types of chemical reactions: synthesis and decomposition
Synthesis reaction: a reaction in which two reactants combine to make a larger or more complex product
General pattern: A + B  AB
Decomposition reaction: a reaction in which a large or more complex molecule breaks down to form two (or more) simpler products
General pattern AN  A + B

6. C3.5 Types of chemical reactions: Single and double displacement
Single displacement reaction: A reaction in which an element displaces another element in a compound, producing a new compound and a new element.
General pattern: A + BC  AC + B
Double displacement reaction: A reaction that occurs when elements in different compounds displace each other or exchange places, producing two new compounds.
General Pattern: AB + CD  AD + CB