Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
Simple differences between mixtures and compounds
19 practice questions
Practice questions
1–8 of 8 · Easy
Question 1
1 mark · Easy
Answer and see the solution →State whether sodium chloride (table salt) is an element, a compound, or a mixture.
Question 2
3 marks · Easy
Answer and see the solution →The table below shows the melting points of three samples. Use the data to answer the questions.
Melting points of three substances Sample Melting point (°C) A 801 B 112–130 C 0 (a)[1 mark]Which sample is a pure substance? Explain your answer.
(b)[1 mark]State what the melting range in sample B tells you about its purity.
(c)[1 mark]The boiling point of sample C is 100°C. Is C most likely a pure substance or a mixture? Give a reason.
Question 3
2 marks · Easy
Answer and see the solution →Explain why a mixture of ethanol and water does not have a sharp boiling point.
Question 4
3 marks · Easy
Answer and see the solution →Classify each substance in the table as an element, a compound, or a mixture.
Classification of substances Substance Classification Argon Sea water Ammonia (NH₃) Question 5
1 mark · Easy
Answer and see the solution →State what you would observe about the melting behaviour of a pure substance.
Question 6
3 marks · Easy
Answer and see the solution →A student has the following substances:
Substance Description Hydrogen Colourless gas, only one kind of atom Calcium oxide Solid, contains calcium and oxygen chemically combined Air Mixture of different gases (a)[1 mark]Which substance is an element? Explain your answer.
(b)[1 mark]Which substance is a compound? State its chemical formula.
(c)[1 mark]Why is air described as a mixture?
Question 7
2 marks · Easy
Answer and see the solution →A liquid mixture has a boiling range from 83°C to 97°C. Calculate the difference in temperature across its boiling range.
Question 8
2 marks · Easy
Answer and see the solution →A sealed container holds 36 g of water and 12 g of oxygen gas. Calculate the total mass of compound present and the total mass of element present in the container. Identify which substance is a compound and which is an element.