STARTER Match the formula on the front of your booklet with it’s correct name You have 3 min!

H NO3 Zn Cl2 H2 SO4 Cu Cl2 Ca (OH)2 Ca CO3 Ag Br Na OH Ag2 O Ca SO4 Cu O Mg O Ag NO3 H Cl Na2 SO4 Na Cl

Balancing Equations Everyone should: Be able to balance simple equations that use up to 3 valence electrons Most people will: Balance equations using compounds like OH- NO3 - SO4 2- Some people will: Be able to balance equations with unusual compounds not covered in class

IMPORTANT ATOMS CANNOT BE CREATED OR DESTROYED!

Remember: Hydrogen and Chlorine are diatomic Hydrogen + chlorine  hydrogen chloride H2 + Cl2  HCl Remember: Hydrogen and Chlorine are diatomic  + REACTANTS 2 H atoms 2 Cl atoms PRODUCTS 1 H atom 1 Cl atom This is impossible as it implies that atoms have been destroyed.

What do we do? We need to make the number of atoms equal on both sides of the equation, in order to get the equation to BALANCE.

What do we do? We need to make the number of atoms equal on both sides of the equation, in order to get the equation to BALANCE. Equation is now balanced, as there are the same number hydrogen atoms (2) and the same number of chlorine atoms (2) on the products and reactant side.

Firstly you need an equation with the correct “formulae” in……… Firstly you need an equation with the correct “formulae” in………. You’ll probably be given this in the question Just like this one Mg + O2  MgO Then all you do is list the atoms that are involved on each side of the arrow Mg + O2  MgO Mg O

Mg + O2  MgO Mg + O2  MgO 2 Then start balancing: [1] Just count up the atoms on each side Mg + O2  MgO Mg O 1 1 2 1 [2] The numbers aren’t balanced so then add “BIG” numbers to make up for any shortages Mg + O2  MgO Mg O 1 2 2 2 2 And adjust totals

WE SAY THAT THE EQUATION IS BALANCED!! But the numbers still aren’t equal, so add another “BIG” number 2 Mg + O2  MgO Mg O 1 2 2 And adjust totals again NOW BOTH SIDES HAVE EQUAL NUMBERS OF ATOMS WE SAY THAT THE EQUATION IS BALANCED!!

Why didn’t anyone tell me it was so easy to balance equations???!!! GROUP ACTIVITY: Try to balance these equations using the same method You have 5 min! Why didn’t anyone tell me it was so easy to balance equations???!!! [1] Na + Cl2  NaCl [2] CH4 + O2  CO2 + H2O [3] Li + HNO3  LiNO3 + H2 [4] Al + O2  Al2O3

How did you get on?? Here are the answers: [1] 2 Na + Cl2  2 NaCl [2] CH4 + 2 O2  CO2 + 2 H2O [3] 2 Li + 2 HNO3  2 LiNO3 + H2 [4] 4 Al + 3 O2  2 Al2O3

Examples 2 2 2 2 3 4 2 2 2