Year 7 Science · Unit 2 · Lesson 16
Foundation Worksheet
Learning Goals
Match each material to its composition
Draw a line connecting each material on the left to its correct composition on the right. Or write the matching letter next to each material.
| Material | Your answer | Composition |
|---|---|---|
| Air | A. Copper (Cu) + Zinc (Zn) | |
| Seawater | B. Iron (Fe) + Carbon (C) | |
| Steel | C. ~78% N₂, 21% O₂, ~1% Ar, ~0.04% CO₂ | |
| Bronze | D. Water + dissolved salts (~3.5% NaCl + minerals) | |
| Brass | E. Copper (Cu) + Tin (Sn) | |
| Pure water | F. H₂O only — a single compound, no dissolved minerals |
Odd one out
Circle the item that does not belong in each group. Then explain why it doesn't fit.
| # | Group | Your answer (odd one + reason) |
|---|---|---|
| 1 | Steel Bronze Brass Gold | |
| 2 | Air Seawater Steel Distilled water | |
| 3 | Nitrogen Oxygen Argon Salt |
1. A scientist boils seawater in a flask until all the water evaporates. She notices a white solid is left behind. What does this tell us about seawater? Use the word mixture in your answer.
2. Engineers often use steel instead of pure iron to build bridges and cars. Name ONE reason why steel is a better choice than pure iron, and explain why steel is still classified as a mixture.
Wrap Up
In one sentence, what was the main idea of this lesson?