Combustion quiz for grade 8 science: 10 questions with answers

by aicko
28 October 202628 October 2026

Quick answer: Combustion is a fast reaction of a fuel with oxygen that releases heat and light. This grade 8 science quiz checks combustion with 10 multiple-choice questions and instant feedback; every answer comes with a short explanation.

Combustion quiz for grade 8 science: 10 questions with answers

This combustion quiz for grade 8 science has quick multiple-choice questions with instant feedback. Need a refresher first? Read the lesson or do the worksheet on combustion.

Choose the best option for each question. Only one is correct; the others reflect common mistakes about fire, burning equations and carbon monoxide.

Level: Grade 8 science (Year 9 · Class 8) · Curriculum: MS-PS1-2

Contents

Combustion quiz: the questions

Which three things make up the fire triangle?

What are the products of complete combustion of methane?

What does limewater do when carbon dioxide is bubbled through it?

Which gas is produced by incomplete combustion and is poisonous?

A fire blanket puts out a pan fire by

Which balanced equation is correct?

A yellow, sooty flame on a gas heater suggests

Why is carbon monoxide hard to notice?

Which fuel makes no carbon dioxide when it burns?

Steel wool gains mass when it burns because

Define combustion. — Reaction of a fuel with oxygen releasing heat and light.

Fire triangle parts? — Fuel, oxygen, heat.

Methane burning equation? — CH₄ + 2 O₂ → CO₂ + 2 H₂O

Test for carbon dioxide? — Limewater turns milky.

White solid in limewater test? — Calcium carbonate.

What is incomplete combustion? — Burning with limited oxygen.

Products of incomplete combustion? — Carbon monoxide and soot.

Why is CO dangerous? — Colourless, odourless, stops blood carrying oxygen.

Colour of complete-combustion flame? — Blue.

Is combustion exothermic? — Yes, it releases energy.

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