Free Elements, compounds & mixtures questions for IGCSE Chemistry (0620), part of Atoms, elements & compounds. Each question has the answer and the marking points an examiner would look for.
Generate a full Elements, Compounds & Mixtures worksheet →All Atoms, elements & compounds questionsAir, sea water, carbon dioxide and steel are compared.
1 The components of a mixture can be separated by physical methods.
2 Air is a mixture of elements and compounds.
3 Steel is a compound of iron and carbon.
Which statements are correct?
Answer: B
Which term is described by this statement?
“A substance containing two or more elements chemically combined.”
Answer: A
Air, sea water, carbon dioxide and steel are compared.
1 Steel is a compound of iron and carbon.
2 Carbon dioxide is a compound because its elements are chemically combined.
3 Sea water has a fixed boiling point because it is mostly water.
Which statements are correct?
Answer: D
Iron filings and sulfur powder are mixed and then heated strongly. A black solid forms.
Describe how iron could be separated from the mixture before heating.
Explain why the iron cannot be removed with a magnet after heating.
State two differences between a mixture and a compound.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | use a magnet use a magnet B1 | 1 |
| (b) | compound formed, iron chemically combined a chemical reaction has formed iron(II) sulfide, a compound B1 the iron is chemically combined so it is no longer magnetic B1 | 2 |
| (c) | fixed composition; separation; properties Any 2 of: a compound has a fixed composition, a mixture does not; a compound can only be separated chemically; a compound has different properties from its elements B2 | 2 |
Distinguish between atoms, molecules and ions.
State what is meant by a molecule.
Give an example of a molecule of an element and a molecule of a compound.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | two or more atoms covalently bonded two or more atoms chemically (covalently) bonded together B1 | 1 |
| (b) | O₂; H₂O element: O₂/N₂/H₂/Cl₂ B1 compound: H₂O/CO₂/CH₄ B1 | 2 |
Substances can be classified as elements, compounds or mixtures.
Define an element.
Define a compound.
Explain why air is a mixture and not a compound.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | cannot be broken down chemically a substance made of only one type of atom (that cannot be broken down into simpler substances) B1 | 1 |
| (b) | two or more elements chemically combined in fixed proportions two or more elements B1 chemically combined (in fixed proportions) B1 | 2 |
| (c) | not chemically joined; variable composition the gases in air are not chemically combined B1 its composition can vary / it can be separated by physical means B1 | 2 |
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