Year 7 Science · Unit 2 · Lesson 4

Pure Substances vs Mixtures

Foundation Worksheet

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Date

Class

Learning Goals

Classify substances as pure substances, homogeneous mixtures or heterogeneous mixtures.
Explain what "pure" means in chemistry and why it differs from everyday use.
Match key terms (pure substance, mixture, homogeneous, heterogeneous, solution) to their definitions.

Warm Up

Sort it!

Write each substance from the pool into the correct category box below.

Distilled water Seawater Pure gold Trail mix Saltwater Beach sand Oxygen gas (lab cylinder) Air Muesli Table sugar (sucrose)

Pure Substance

Homogeneous Mixture

Heterogeneous Mixture

Match each term to its definition

Draw a line connecting each term on the left to its correct definition on the right. Or write the matching letter next to each term.

Term	Your answer	Definition
Pure substance		A. A homogeneous mixture where one substance is dissolved in another.
Mixture		B. A mixture where you can clearly see different parts — like muesli or beach sand.
Homogeneous		C. Matter made of only one kind of particle — like distilled water or pure gold.
Heterogeneous		D. Two or more substances physically combined; each keeps its own properties.
Solution		E. A mixture that looks the same all the way through — every scoop is identical.
Particle diagram		F. A drawing that shows how particles are arranged to reveal whether a substance is pure or mixed.

1. A student says "100% pure orange juice is a pure substance." Is this correct? Explain using the chemistry meaning of "pure".

Recall 2 marks

2. Describe one physical method you could use to separate seawater into its parts. Name the method and explain what it does.

Recall 2 marks

Wrap Up

In one sentence, what was the main idea of this lesson?