Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Chapter
Covalent Bonding
68 practice questions
Topics covered
Practice questions
11–12 of 12 · Hard
Question 11
7 marks · Hard
Answer and see the solution →This question is about how the physical properties of substances are linked to their structures and electrical conductivity.
(a)[0 marks]The table shows data for some simple molecular and giant covalent substances:
Melting and boiling points of selected substances. Substance Relative molecular mass / Mr Melting point / °C Boiling point / °C Chlorine (Cl₂) 71 -101 -34 Bromine (Br₂) 160 -7 59 Iodine (I₂) 254 114 184 Diamond – 3550 4830 (b)[2 marks]Using data from the table, describe and explain how the melting and boiling points of the halogens change as the relative molecular mass increases.
(c)[2 marks]Explain why the melting point of diamond is much higher than those of the halogens listed, using ideas about structure and bonding.
(d)[3 marks]State whether graphite conducts electricity. Suggest, based on your knowledge of its structure, why this is different from diamond and the halogens.
Question 12
7 marks · Hard
Answer and see the solution →This question is about how the type of structure affects properties in covalent and giant covalent substances.
(a)[2 marks]Explain what is meant by a 'simple molecular structure', using water (H₂O) as an example.
(b)[3 marks]Compare the structure and bonding found in C₆₀ fullerene with that in graphite.
(c)[2 marks]State which would have a higher melting point, graphite or C₆₀ fullerene. Explain your answer in terms of their bonding and structures.