States of matter

Junior High 7 questions

What states of matter means

You learn how solids, liquids and gases behave, and how they change from one state to another. This helps you explain everyday events such as ice melting, water boiling and clothes drying.

What you will practise

Identify solids, liquids and gases from their properties
Match each state to particle arrangement and movement
Name changes such as melting, freezing and evaporation
Use simple examples from daily life to show state changes

Before you start

You should already know basic particle ideas and simple words for heat and temperature. It also helps if you can recognise common materials around you.

Worked example

One question from this skill's own question bank, shown with its full working.

Question

What is the process of a liquid turning into a gas called?

Freezing
Melting
Evaporation
Condensation

Answer: Evaporation

Working: Evaporation is when a liquid changes into a gas.

Common mistakes to avoid

Thinking all changes of state need only cooling. Some changes need heating, while others need cooling.
Mixing up melting and evaporation. Melting changes a solid to a liquid, while evaporation changes a liquid to a gas.
Saying gases are packed tightly like solids. Gas particles are far apart and move freely.
Forgetting that ice melts at 0°C at standard pressure. Learn this as a key reference point.

Curriculum and exam alignment

Ghana GES Basic 7 to 9 syllabusBECE

This topic normally appears in Junior High School Chemistry when learners study matter, particle ideas and physical changes. It supports preparation for BECE questions on states, properties and common changes of state.

Curriculum notes are a general guide to where this work normally sits. Always check the syllabus your school or examination body is currently using.