1.  Chemistry, Equations and you!!!! Balancing Equations

2. Learning Objective  To explain what is meant by a “chemical reaction”  To be able to name some chemical compounds  To be able to balance equations on your work sheet

3. So what are Equations?  Information  Format  Symbol/Naming  Subscript?  Balanced

4. Information  What is a chemical equation? Reactants Products  Chemical Reaction

5. Format Left Right Reactants Products

6. Symbols Remember Periodic table?

7. Symbols/Naming Remember Periodic table? RULE 1: If two identical elements combine the name does not change This happens with the following elements: H 2 N 2 O 2

8. Symbols/Naming RULE 2: When two elements join and one is a halogen, oxygen or sulphur the name ends with ____ide  e.g. Magnesium + oxygen → magnesium oxide Halogens

9. Symbols/Naming RULE 2: When two elements join and one is a halogen, oxygen or sulphur the name ends with ____ide  e.g. Magnesium + oxygen → magnesium oxide Sodium + chlorine Magnesium + fluorine

10. Rule 3: When three or more elements combine, and one of them is oxygen, the name ends with ____ate  e.g. Copper + sulphur + oxygen → Copper sulfate Calcium + carbon + oxygen Potassium + carbon + oxygen

11. Symbols/Naming RULE 4: When three or more elements combine, and two of them are hydrogen and oxygen, the name ends with hydroxide  e.g. Sodium + hydrogen + oxygen → Sodium hydroxide Potassium + hydrogen + oxygen Calcium + hydrogen + oxygen

12. Subscript? Oxygen gas   O 2 Water  H 2 O

13. Subscript? 2H 2 O or 2(H 2 O) or 2 oxygen or

14. Step One K + Cl ₂ → KCl ElementBefore ReactionAfter K11 Cl21 LOOK ✔ ✔ ✔ ✗

15. Step Two K + Cl ₂ → 2 KCl ElementBefore ReactionAfter K12 Cl22 ✔ ✔ ✔ ✗

16. Step Three 2 K + Cl ₂ → 2 KCl ElementBefore ReactionAfter K22 Cl22 ✔ ✔ ✔ ✔

17. Step One H 2 + 0 2 → H 2 0 LOOK ElementBefore ReactionAfter H22 O21 ✔ ✔ ✔ ✗

18. Step Two H 2 + 0 2 → 2 H 2 0 ElementBefore ReactionAfter H24 O22 ✔ ✔✔ ✗

19. Step Three 2 H 2 + 0 2 → 2 H 2 0 ElementBefore ReactionAfter H44 O22 ✔ ✔✔ ✔

20. What have we learnt?  To explain what a reactant and product are!  To use our periodic table to name chemical symbols!  How subscript is used in Chemistry!  How to balance chemical equations!

21. Plenary  Group 1 on the periodic table refers to the Reactive metals as we progress down the group the metals become More reactive  When 2 or more elements combine it makes a Compound  The two types of particles found in a nucleus of an atom are Protons & Neutrons  The mass number on the periodic table refers to the total number of Protons & Neutrons  Isotopes are: different atomic forms of the same element, which have the same number of protons but different numbers of neutrons.