S

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:

H2

N2

O2

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 oxideSodium + 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 O2

Water H2O

Subscript?

2H2O or 2(H2O) or 2 oxygen

or or

Step One

K + Cl₂ → KCl Element Before Reaction After

K 1 1

Cl 2 1

LOOK

✔ ✔✔ ✗

Step Two

K + Cl₂ → 2KCl Element Before Reaction After

K 1 2

Cl 2 2✔ ✔

✔ ✗

Step Three

2K + Cl₂ → 2KCl Element Before Reaction After

K 2 2

Cl 2 2✔ ✔

✔ ✔

Step One

H2 + 02 → H20 LOOK

Element Before Reaction After

H 2 2

O 2 1

✔ ✔✔ ✗

Step Two

H2 + 02 → 2H20

Element Before Reaction After

H 2 4

O 2 2

✔✔✔✗

Step Three

2H2 + 02 → 2H20

Element Before Reaction After

H 4 4

O 2 2

✔✔✔✔

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.