Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
Simple differences between mixtures and compounds
19 practice questions
Practice questions
1–8 of 8 · Normal
Question 1
2 marks · Normal
Answer and see the solution →State whether each of the following substances is an element, a compound, or a mixture. (a) Silver (b) Seawater
Question 2
4 marks · Normal
Answer and see the solution →(a)[2 marks]Explain how you could use melting point to distinguish between pure salt and a mixture of salt and sand. (2 marks)
(b)[2 marks]Predict how the boiling point of a mixture of water and alcohol compares to the pure substances, and explain your answer. (2 marks)
Question 3
3 marks · Normal
Answer and see the solution →A sample contains 8 g of oxygen and 2 g of hydrogen. Describe whether this sample is a compound or a mixture, and state the formula of the compound (if any) that could be formed by these elements. Show your calculation.
Question 4
3 marks · Normal
Answer and see the solution →Paracetamol is a pure compound. Explain, using ideas about melting and boiling points, how you could prove that a sample of paracetamol is not a mixture. (3 marks)
Question 5
4 marks · Normal
Answer and see the solution →Sample table showing types of substances found in air. Substance Type Oxygen Water vapour Carbon dioxide Helium Dust particles (a)[3 marks]Complete the table by identifying each substance as an element, a compound, or a mixture. (3 marks)
(b)[1 mark]Is air itself an element, a compound, or a mixture? Explain your answer. (1 mark)
Question 6
1 mark · Normal
Answer and check →Which statement describes a key difference between a pure substance and a mixture?
- A.A pure substance has a sharp melting point; a mixture melts over a range.
- B.A pure substance can be separated by physical means only.
- C.A mixture contains only one type of atom.
- D.A pure substance always contains two different elements.
Question 7
2 marks · Normal
Answer and see the solution →State whether each of the following is an element, a compound, or a mixture: (a) Hydrogen chloride gas (b) Brass
Question 8
4 marks · Normal
Answer and see the solution →(a)[2 marks]Describe the melting point behaviour of a pure solid and a mixture during heating. (2 marks)
(b)[2 marks]A student finds that her sample of a white solid melts over the range 150°C to 163°C. What does this suggest about the purity of the sample? (2 marks)