UNIT OVERVIEW

Everything around us is made of substances. Some substances are simple, made of just one type of atom. Others are more complex, made when different atoms join together. In this unit, you will learn how scientists describe and organise these substances, and what happens when substances change into new substances.

What you will learn:

• The difference between elements, compounds, and mixtures
• How to read and understand simple chemical formulas
• How to name common compounds
• What happens during a chemical reaction
• How to write and balance simple chemical equations

Why this matters:

Understanding how substances combine and change helps explain everyday things:

• Why salt dissolves in water but sand does not
• Why iron gates rust over time
• Why burning wood produces smoke and ash
• How your body gets energy from food

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