1. CHEMICAL Equations

2. Chemical Changes vs. Physical Changes
Physical changes are changes in the physical appearance, state or size of a substance.
Chemical changes are changes in the arrangements and connections between ions and atoms, and a change in chemical properties.

3. Example of a physical change: Melting Ice

4. Example of a chemical change: “Burning” Magnesium Ribbon

5. Chemical Equations
Is a representation (in words or symbols) of a chemical reaction
Provides information about:
The reactants (the starting materials)
The products (the materials produced )

7. WORD EQUATION
Not much information other than the elements/compounds involved
Potassium metal + oxygen gas  potassium oxide
Products are on the right-hand side of the equation
Reactants are on the left-hand side of the equation
+ sign means “reacts with”
Arrow means produces/yields/ makes

8. Components of a Chemical Equation
6 CO2(g) + 6 H2O(g)  C6H12O6(s) + 6 O2(g)
Coefficients- numbers in front of the formulae that show the ratio of the reactant(s) and product(s)
States of matter- indicate the state of the substance reacting or being produced ; (g)= gas, (l)= liquid, (aq)= aqueous, and (s) = solid

9. States of matter: A small piece of sodium which lived in a test tube fell in love with the Bunsen burner: "Oh Bunsen, my flame. I melt whenever I see you . . .", the sodium pined. "It's just a phase you're going through", replied the Bunsen burner.

10. Counting Atoms in Equations
In order to determine how many atoms of each element are involved in a chemical equation you must always watch two things:
The subscripts in the formula
The coefficient in front of the formula
CuCl2
Means 2 chlorine atoms/ ions in the molecule
Means two water molecules, each of which has 2 H atoms and 1 oxygen atom
2H2O

11. Examples of counting atoms
How many oxygen atoms are indicated by each formula: CO
C6H12O6
2 SO2
Mg(OH)2
3Sn(Cr2O7)2 1 6 4 2 42

12. ASIDE! THE “FANCY SEVEN” 
When these atoms are elements (i.e. they are all on their own) they are DIATOMIC (they are in pairs)
e.g. N2 O2 F2 Cl2 Br2 I2 H2

13. Law of Conservation of Mass
This LAW states that the total mass of all products always equals the total mass of all reactants