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The structures of diamond and graphite are shown - Edexcel - GCSE Chemistry - Question 6 - 2015 - Paper 1
Question 6
The structures of diamond and graphite are shown. (a) (i) State the maximum number of covalent bonds formed by a carbon atom in a diamond crystal. (ii) Which of t... show full transcript
Worked Solution & Example Answer:The structures of diamond and graphite are shown - Edexcel - GCSE Chemistry - Question 6 - 2015 - Paper 1
Step 1
State the maximum number of covalent bonds formed by a carbon atom in a diamond crystal.
Answer
In a diamond crystal, a carbon atom is bonded to four other carbon atoms through covalent bonds. Therefore, the maximum number of covalent bonds formed by a carbon atom in a diamond crystal is four.
Step 2
Which of the following statements about diamond and graphite is true?
Answer
The correct statement is D. they both have high melting points. Diamond has a very high melting point due to the strong covalent bonds in its structure, and graphite also has a high melting point, though it is composed of layers that can slide over one another.
Step 3
Explain, in terms of its structure, why graphite is able to be used as a lubricant.
Answer
Graphite consists of layered structures where carbon atoms are arranged in hexagonal planes. The layers are held together by weak van der Waals forces, allowing them to slide over one another easily. This slip of the layers makes graphite effective as a lubricant, as it reduces friction between surfaces.