Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
The physical properties of ionic substances
19 practice questions
Practice questions
11–19 of 19
Question 11
3 marks · Normal
Answer and see the solution →Explain why sodium chloride forms a giant ionic lattice instead of individual molecules. In your answer, refer to the charges on the ions and the overall structure.
Question 12
1 mark · Normal
Answer and check →Which statement best explains why ionic compounds, such as sodium chloride, are often crystalline?
- A.Because their ions are free to move in the lattice.
- B.Because the ions are arranged in a regular repeating pattern.
- C.Because they are made up of molecules.
- D.Because they contain only one type of atom.
Question 13
2 marks · Normal
Answer and see the solution →State what is meant by a 'giant ionic lattice' as found in sodium chloride.
Question 14
4 marks · Normal
Answer and see the solution →(a)[2 marks]Explain why a large amount of energy is required to melt an ionic compound such as sodium chloride.
(b)[2 marks]Compare the melting points of sodium chloride and potassium chloride. Both are ionic, but sodium chloride melts at 801 °C and potassium chloride at 770 °C. Suggest a reason for this difference.
Question 15
3 marks · Normal
Answer and see the solution →A student looks at two samples of different ionic compounds under a microscope. Sample A forms visible cube-shaped grains, but Sample B appears as a fine white powder and individual grains are not visible to the naked eye.
Using ideas about the arrangement of ions, calculate and explain how the crystalline property of ionic compounds is demonstrated in both samples.
Question 16
4 marks · Normal
Answer and see the solution →Two ionic compounds, sodium chloride (NaCl) and magnesium oxide (MgO), have the following melting points:
Compound Melting Point (°C) NaCl 801 MgO 2852 Analyse the data. Explain why magnesium oxide has a much higher melting point than sodium chloride. Your answer should consider the type of particles and the forces between them.
Question 17
2 marks · Hard
Answer and see the solution →Explain, in terms of the forces present, why ionic compounds such as sodium chloride have high boiling points.
Question 18
5 marks · Hard
Answer and see the solution →Crystals of sodium chloride are often seen as large, regular cubes under the microscope.
(a)[1 mark]State what is meant by the term 'crystalline' when describing a substance.
(b)[2 marks]Describe the arrangement of ions in the giant ionic lattice of sodium chloride as it relates to its crystalline appearance.
(c)[2 marks]Explain why the regular arrangement of ions results in sodium chloride crystals having a regular shape.
Question 19
2 marks · Hard
Answer and see the solution →Describe the arrangement of sodium and chloride ions in the giant ionic lattice of sodium chloride.