Pearson Edexcel IGCSE · Chemistry

Elements, compounds and mixtures: Practice Questions

5 multiple-choice questions marked as you go, and 5 written questions with worked solutions. All on Elements, compounds and mixtures.

10 questions19 marksFree, no account

Question 1

1 mark

Which mixture can be separated into its components using the technique of filtration?

Question 2

1 mark

A student performs a chromatography experiment. The solvent front moves \(12.0 \text{ cm}\) and a red dye moves \(4.8 \text{ cm}\). What is the \(R_f\) value of the red dye?

Question 3

1 mark

A chromatogram is obtained for an unknown food dye. It shows three distinct spots at different heights from the baseline. One of the spots aligns perfectly with the spot of a known banned additive. Which conclusion is most accurate?

Question 4

1 mark

Which of the following best defines a compound in chemical terms?

Question 5

1 mark

A student performs paper chromatography on a dye. The solvent front moves a distance of \( 15.0\text{ cm} \) from the baseline. If the component has an \( R_f \) value of \( 0.64 \), what is the distance moved by the spot from the baseline?

Question 6

2 marks

Classify the following substances as an element, a compound, or a mixture:
i) Magnesium ribbon
ii) Carbon dioxide gas

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Question 7

3 marks

In a paper chromatography experiment, explain why it is essential that the level of the solvent is below the baseline where the spots are placed.

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Question 8

2 marks

In a chromatography experiment, if a substance is insoluble in the chosen solvent, where will the spot be located on the final chromatogram?

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Question 9

3 marks

Substances can be classified into different categories based on their composition.

a) Define the term solvent.

b) A student has a mixture of sand and water. Explain why filtration is a suitable method to separate the sand from the water.

c) A different mixture contains sodium chloride dissolved in water. Name the experimental technique used to obtain pure water from this mixture.

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Question 10

4 marks

Substances can be classified as elements, compounds, or mixtures.

a) For each of the following, state whether it is an element, a compound, or a mixture:

i) Air
ii) Distilled water
iii) Oxygen gas
iv) Salt dissolved in water

b) Describe how you would separate a mixture of sand and iron filings, explaining the principle behind the chosen method.

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