Year 7 Science · Unit 2 · Lesson 16
Apply Worksheet
Learning Goals
Read the graph — composition of air
Study the bar chart, then answer the three questions below.
Data: Bureau of Meteorology / standard atmospheric chemistry values
(a) Describe what the chart tells you about the most common gas in air.
(b) Estimate what percentage of air is NOT nitrogen or oxygen. Show your working.
(c) People often say "we breathe oxygen." Based on the chart, why is this statement a simplification? Explain using data from the graph.
Compare two — Pure Copper vs Brass
Complete the table to compare pure copper and brass. Use what you know from the lesson.
| Feature | Pure Copper | Brass (Cu + Zn) |
|---|---|---|
| Main element(s) | ||
| Hardness (relative) | ||
| Resistance to corrosion | ||
| Colour / appearance | ||
| One common use |
1. A musician's trumpet is made from brass rather than pure copper. Using evidence from the comparison table, give TWO reasons why brass is a better choice for making musical instruments.
2. A student says: "Brass must be a compound because it's made by melting copper and zinc together." Do you agree? Explain why or why not, using the correct scientific terms.
Wrap Up
In one sentence, what was the main idea of this lesson?