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Covalent bonding

Covalent bonding

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Question 13

This question is about different structures of group 14 oxides: silicon dioxide (SiO2\text{SiO}_2SiO2​) and carbon dioxide (CO2\text{CO}_2CO2​).

a.

Name the type of chemical bond that exists between the atoms within both silicon dioxide and carbon dioxide.

[1]
b.

Explain, in terms of structure and bonding, why silicon dioxide has a very high melting point.

[3]
c.

Carbon dioxide has a simple molecular structure. Explain why it has a very low sublimation temperature.

[2]
d.

Cristobalite and quartz are two different crystalline forms of silica. They can be interconverted according to the equation:

SiO2(cristobalite)⇌SiO2(quartz)ΔH=−1.5 kJ/mol \text{SiO}_2(\text{cristobalite}) \rightleftharpoons \text{SiO}_2(\text{quartz}) \quad \Delta H = -1.5 \text{ kJ/mol} SiO2​(cristobalite)⇌SiO2​(quartz)ΔH=−1.5 kJ/mol

Would a low or a high temperature favour the conversion of cristobalite into quartz? Give a reason for your choice.

[2]
Markscheme

Covalent bonding Questions

  1. IGCSE
  2. /Chemistry
  3. /Covalent bonding

15 exam-style questions on Edexcel IGCSE Chemistry Covalent bonding. Each one has a worked solution and a mark scheme showing where the marks go.

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