Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Unit
Principles of Chemistry
991 practice questions
Topics covered
- States of Matter102 practice questions
- Elements, Compounds and Mixtures69 practice questions
- Atomic Structure108 practice questions
- The Periodic Table103 practice questions
- Chemical Formulae, Equations and Calculations Part 119 practice questions
- Chemical Formulae, Equations and Calculations Part 2144 practice questions
- Ionic Bonding143 practice questions
- Covalent Bonding68 practice questions
- Metallic Bonding19 practice questions
- Electrolysis198 practice questions
Practice questions
111–120 of 991
Question 111
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 112
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 113
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 114
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 115
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 116
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 117
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 118
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)
Question 119
2 marks · Hard
Answer and see the solution →A student is given three samples: Sample A contains only carbon atoms, Sample B contains molecules of carbon dioxide, and Sample C contains both carbon dioxide and oxygen gas mixed together. Classify each sample as an element, a compound, or a mixture.
Question 120
5 marks · Hard
Answer and see the solution →A researcher is investigating two samples: Sample X is a pure substance, and Sample Y is a mixture. She records the melting and boiling behaviour of each sample while heating.
(a)[2 marks]Describe the expected melting behaviour of Sample X and Sample Y as they are heated.
(b)[2 marks]Explain how boiling point data can be used to decide whether Sample X or Sample Y is pure or a mixture.
(c)[1 mark]A sample melts sharply at 801°C and boils at exactly 1465°C with no temperature change during the phase transitions. State whether it is pure or a mixture, and justify your answer with evidence from the data.