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

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

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

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

Format Left Right Reactants Products

Symbols Remember Periodic table?

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

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

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

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

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

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

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

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

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

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

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

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

Step Three 2 H → 2 H 2 0 ElementBefore ReactionAfter H44 O22 ✔ ✔✔ ✔

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!

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.