中文（繁體）
中文（简体）
English
P4 General Studies: Air, Burning and Rusting (Paper 1: basics)
Tutor Prep Guide · composition of air, conditions for burning, conditions for rusting and ways to prevent rust
P4 General Studies: Air, Burning and Rusting (Paper 1: basics)
The first paper builds the base: learn the shares of the gases in air and be clear about what burning and rusting each need.
Direct answers Before answering, ask whether oxygen and water are present, and the two conditions become clear.
01 Paper details (check answers afterwards)
| Item | Detail |
|---|---|
| Questions | 10 |
| Suggested time | 20 |
| Difficulty mix | Foundation 3 · Intermediate 3 · Challenge 3 · Error redo 1 |
| Chapter | Chapter: P4 General Studies: Air, Burning and Rusting |
| Level | composition of air, conditions for burning, conditions for rusting and ways to prevent rust |
02 Questions (10 items)
- FoundationWhich gas is the most abundant in air?
- FoundationWhich gas in the air is needed for burning?
- FoundationWhich two conditions must both be present for iron to rust?
- IntermediateAbout what share of air is oxygen?
- IntermediateWhat happens to a burning candle once a glass is placed over it?
- IntermediateWill a nail rust after a week in a sealed jar with a drying agent?
- ChallengeAbout how many millilitres of oxygen are in 1 litre of air?
- ChallengeWhy is carbon dioxide used to put out fires?
- ChallengeWhat kind of change is iron rusting?
- Error redoA pupil says rusting is only iron getting wet with no new substance. What is wrong?
03 Answers and one-line notes
| # | Answer | One-line note |
|---|---|---|
| 1 | Nitrogen | Nitrogen makes up about 78 per cent of air, more than oxygen. |
| 2 | Oxygen | Without oxygen a flame goes out, which is why putting out a fire means cutting off oxygen. |
| 3 | Oxygen and water | Both are needed, which is why iron lasts much longer in a dry place. |
| 4 | About 21 per cent | Nitrogen is about 78 per cent and oxygen about 21 per cent, with the rest carbon dioxide and other gases. |
| 5 | It goes out after a while | The oxygen inside the glass is used up, so the flame can no longer burn. |
| 6 | No, it will not rust | There is no water vapour in the jar, so one of the two conditions for rusting is missing. |
| 7 | About 210 millilitres | 1 000 millilitres times 21 per cent gives 210 millilitres, roughly one fifth. |
| 8 | It is denser than air, so it sinks and covers the fire | Being heavier it settles over the flames and keeps oxygen away. |
| 9 | A chemical change | Rusting makes a new substance, rust, so it is a chemical change. |
| 10 | Rusting makes a new substance, rust, so it is a chemical change | Rust has a different colour and composition from iron, and it weighs more than the iron did. |
04 What to do after marking
- After marking, redo only the wrong items and write down which step went wrong (formula, unit, or misread number).
- Repeat the same item two days later; move to the next paper only when both attempts are correct.
- Parents only need the answer and note columns; there is no need to explain every item.
After paper one, try paper two to fix the air composition figures in memory.Tutor Registration →
Questions and answers are written originally by the TutorZone team and are not taken from any school, publisher or examination authority paper. Every value is checked by computer.