What is air?

What is the percentage of oxygen in the air?

What is the percentage of nitrogen in the air?

Are there relatively small of relatively large amounts of water vapour, carbon dioxide, neon and argon in the air?

What is dry air?

How can dry air be used to obtain oxygen and nitrogen?

What can elements burn in air to form?

What do water-soluble oxides of metals give?

What do water-soluble oxides of non-metals give?

What are substances reacting with when they burn in air?

Describe the test for oxygen

What do oxidation and reduction reacts involve?

What is air polluted by?

How does carbon monoxide arise?

What is the effect of carbon monoxide?

How does sulfur dioxide arise?

What is the effect of sulfur dioxide?

How do oxides of nitrogen arise?

What is the effect of oxides of nitrogen?