This question is about different structures of group 14 compounds: silicon carbide (SiC\text{SiC}SiC) and carbon disulfide (CS2\text{CS}_2CS2).
Name the type of chemical bond that exists between the atoms within both silicon carbide and carbon disulfide.
Explain, in terms of structure and bonding, why silicon carbide has an extremely high melting point.
Carbon disulfide has a simple molecular structure. Explain why it has a very low boiling point.
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/molWould a low or a high temperature favour the conversion of β\betaβ-SiC into α\alphaα-SiC? Give a reason for your choice.
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.