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Covalent bonding

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Question 8

This question is about different structures of group 14 compounds: silicon carbide (SiC\text{SiC}SiC) and carbon disulfide (CS2\text{CS}_2CS2​).

a.

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

[1]
b.

Explain, in terms of structure and bonding, why silicon carbide has an extremely high melting point.

[3]
c.

Carbon disulfide has a simple molecular structure. Explain why it has a very low boiling point.

[2]
d.

Silicon carbide exists in different crystalline forms (polytypes), such as β\betaβ-SiC and α\alphaα-SiC. They can be interconverted according to the equilibrium:

SiC(β)⇌SiC(α)ΔH=+2.1 kJ/mol \text{SiC}(\beta) \rightleftharpoons \text{SiC}(\alpha) \quad \Delta H = +2.1 \text{ kJ/mol} SiC(β)⇌SiC(α)ΔH=+2.1 kJ/mol

Would a low or a high temperature favour the conversion of β\betaβ-SiC into α\alphaα-SiC? Give a reason for your choice.

[2]

Covalent bonding Questions

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