Year 8 Science · Unit 3 · Lesson 9
Foundation Worksheet
Learning Goals
Fill the gap
Choose the correct word from the word bank to complete each sentence. Two words will not be used.
A chemical is any process that produces new substances with different properties from the starting materials. Plants use sunlight, water and carbon dioxide to make glucose and oxygen in the process called . Your body cells break down glucose using oxygen to release energy through . When yeast breaks down sugar without oxygen, the process is called , and it produces carbon dioxide and ethanol. Iron reacts slowly with oxygen and water in the process called , forming a new substance: iron oxide. Enzymes in your stomach and intestines carry out , breaking large food molecules into smaller units your body can absorb.
Match each reaction to its description
Draw a line connecting each reaction on the left to its correct description on the right. Or write the matching letter next to each reaction.
| Reaction | Your answer | Description |
|---|---|---|
| Photosynthesis | A. Iron + oxygen + water → iron oxide; a slow chemical change that weakens metal | |
| Cellular respiration | B. The gradual chemical breakdown of a metal in air or water, reducing its strength | |
| Fermentation | C. CO₂ + H₂O → glucose + O₂; happens in plant cells using sunlight | |
| Rusting | D. Glucose + O₂ → CO₂ + H₂O + energy; releases energy in all living cells | |
| Corrosion | E. Rapid reaction with oxygen releasing heat and light; used in engines and fires | |
| Combustion | F. Yeast + glucose → CO₂ + ethanol; makes bread rise and produces alcoholic drinks |
1. A student says: "Breathing is the same as cellular respiration." Are they correct? Explain clearly why or why not, using what you know about both processes.
2. The Sydney Harbour Bridge maintenance team continuously paints the steel structure. Explain what chemical reaction they are trying to prevent, and why painting the bridge helps prevent it.
Wrap Up
In one sentence, what was the main idea of this lesson?