Air and Its Composition
Dry air is about 78 percent nitrogen and 21 percent oxygen, with small amounts of argon, carbon dioxide and other gases.
▶ Interact
Play with the controls to see the idea in action.
📘 Learn
Dry air is about 78 percent nitrogen and 21 percent oxygen, with small amounts of argon, carbon dioxide and other gases.
- Nitrogen is the most abundant gas
- Oxygen supports combustion
- Carbon dioxide is about 0.04 percent
🧠 Quick quiz
Three questions. Score 2 or more to complete the topic.
What is Air and Its Composition?
Within Chemistry, which covers atoms, bonding, reactions, the periodic table, organic chemistry and the chemistry of everyday life, this topic explains Air and Its Composition. Chemistry links what you can see in the lab to the particles and bonds behind it, so each topic here shows that link in a model.
Check that you can explain Air and Its Composition in your own words and give one example from everyday life. If you can do that, you have understood the core idea.
Understanding Air and Its Composition helps you explain why substances behave as they do, from cleaning products and food to medicines.
Air and Its Composition in detail
Dry air is about 78% nitrogen, 21% oxygen, 0.9% argon and 0.04% carbon dioxide, with traces of other noble gases and variable water vapour. The composition has been fairly stable for about 200 million years.
Early Earth's atmosphere came from volcanic activity, mostly carbon dioxide, and the oxygen came from photosynthesis by algae and plants, which also removed carbon dioxide. Oxygen content can be measured by passing air over heated copper and measuring the volume decrease. Air is separated into its gases by fractional distillation of liquid air.
How the interactive helps you understand Air and Its Composition
Watch the pie chart in the interactive. Use any sliders or buttons it offers to change the values and see how the pie chart responds.
Before you change anything, predict the result. Then change one value at a time and check whether your prediction was right. This is a quick way to build a correct mental model of Air and Its Composition.
Real-life uses and examples
- Use Air and Its Composition to explain what happens in a lab experiment and why.
- Link Air and Its Composition to everyday products such as cleaning agents, food and medicines.
- Read a chemical equation or diagram and work out what Air and Its Composition shows.
Common mistakes to avoid
- Describing what happens without explaining the particles or bonds involved.
- Mixing up the names of substances or ions when you describe Air and Its Composition.
- Learning the definition without testing it. Use the quiz and the interactive to check that you can apply the idea.
Frequently asked questions about Air and Its Composition
What is Air and Its Composition?
Dry air is about 78 percent nitrogen and 21 percent oxygen, with small amounts of argon, carbon dioxide and other gases.
What are the most important points about Air and Its Composition?
The main points are: Nitrogen is the most abundant gas; Oxygen supports combustion; Carbon dioxide is about 0.04 percent.
Why is Air and Its Composition useful?
Understanding Air and Its Composition helps you explain why substances behave as they do, from cleaning products and food to medicines.
How can I practise Air and Its Composition?
Open the interactive at the top of this page and change the controls one at a time. Predict the result before each change, then take the three-question quiz. A score of two or more marks the topic as complete on this device.
Which topics are related to Air and Its Composition?
Related topics in Chemistry include Climate Change and Chemistry, Flame Tests and Cation Tests, Solubility and Saturated Solutions.