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Edexcel IGCSE Chemistry 1.49 Giant covalent structures

Practise explaining the high melting points and hardness of giant covalent structures such as diamond and silicon dioxide.

Syllabus
First assessment 2019
Course
Chemistry 4CH1

Exam points

  • explain high melting points by linking giant covalent lattices to many strong bonds
  • compare SiO2 with simple molecular substances using bonds broken versus forces overcome
  • link hardness in diamond or silicon dioxide to a rigid network of covalent bonds

1.49 Giant covalent structures question 1

[Maximum number: 5]

This question is about the covalent compounds hydrogen chloride and silicon dioxide.

The diagram shows part of the structure of silicon dioxide.

Figure for Question 1.49 Giant covalent structures question 1 — Edexcel IGCSE Chemistry

Silicon dioxide has the same structure as diamond.

Silicon dioxide is very hard and has a very high melting point.
Explain these properties.
Refer to the structure and bonding of silicon dioxide in your answer.

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