Grade 9 · CAPS

Grade 9 Reaction of non-metals with oxygen

Natural Sciences and Technology practice questions with answers

Grade 9 Reaction of Non-metals with Oxygen is part of the CAPS Natural Sciences and Technology curriculum, covering what happens when non-metals such as sulphur and carbon burn in oxygen to form non-metal oxides. Learners practise naming these products, testing for carbon dioxide using lime water, and explaining, in general terms, what type of compound forms when a non-metal reacts with oxygen. The practice questions below are drawn from ReClass's own question bank, based on real Grade 9 CAPS assessments, so learners can check their understanding against the kind of questions used in an actual test.

Worked example

Sulphur powder is burned in oxygen inside a closed glass beaker. Why should the glass beaker be closed with a lid during this reaction?

Answer & explanation

The lid prevents the gas that forms (sulphur dioxide) from escaping into the air, since it is harmful and should not be inhaled.

You'll also practise

  • 2.5 When phosphorus reacts with oxygen, which product is commonly produced and used in matches?
  • When sulphur is burned in oxygen, white fumes form and moist litmus paper turns from blue to red. What is the chemical name of the white fumes?
  • Sulphur is burned in oxygen and the product formed turns moist blue litmus paper red. Are non-metal oxides, such as this one, acidic, basic or neutral?
  • Give the correct term: a compound that is formed when a non-metal burns in oxygen.
  • Explain, in general, what type of product is formed when a non-metal reacts with oxygen.
  • Carbon (found in coal) burns in enough oxygen with a bright, luminous yellow flame and produces an invisible gas with no smell. Name the substance that is a source of carbon for this reaction.
  • Carbon burns completely in oxygen to produce an invisible gas with no smell. Name this gas.
  • Give the chemical formula of the gas produced when carbon burns completely in oxygen.
  • Describe how you could test to prove that carbon dioxide gas was produced by this reaction.
  • An element (sulphur) reacts with oxygen to form an oxide. Give the name of the oxide that forms.

Common mistakes

  • Assuming all oxides are basic, when non-metal oxides are typically acidic.
  • Forgetting that a positive lime-water test (turning milky) confirms carbon dioxide specifically.
  • Mixing up the non-metal reacting with the oxide it produces.

Aligned to CAPS Grade 9 Natural Sciences and Technology — Reaction of non-metals with oxygen.

Check your own understanding

Start a personalised Grade 9 Reaction of non-metals with oxygen practice session on ReClass.