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Chapter 10 — Chapter 10 — Environmental Chemistry

6 topics + Exercise· CHEMISTRY — 9
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Topic 1 · pp. 130–131 · Free

Environmental Chemistry and Composition of Air

Source: Chemistry 9 (PCTB), Ch 10, pp. 130–131

📘Easy summary

Environmental chemistry studies chemicals and pollutants in the environment and their adverse effects. Environmental education aims to make people, especially students, aware of protecting and conserving the environment. Air (by volume): nitrogen 78.0%, oxygen 21.0%, noble gases about 1.0% (argon 0.934%), carbon dioxide 0.04%, water vapour variable (humidity).

⭐Key points

  • Composition varies slightly with place, season, day and night.
  • Fossil fuels and excessive fertilizers/pesticides have damaged the environment since the industrial revolution.

🔬Diagram

Clean dry airN₂ 78%O₂ 21%Noble gases ~1%CO₂ 0.04%Atmosphere

🌿Real-life example

Opening a fizzy drink releases CO₂.

💡Exam tip

  • Remember Ar 0.934% within noble gases.

✅Quick check

1. Most abundant gas in air:

2. CO₂ in air:

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