Explain what is meant by the term covalent bonding.
Describe or draw a dot-and-cross diagram to show the bonding in a molecule of hydrogen sulfide, H2S\text{H}_2\text{S}H2S. Show only the outer electrons.
Substances A and B are covalently bonded and have simple molecular structures. The table below gives the boiling points for substances A and B.
| Substance | Boiling point in ∘C^\circ\text{C}∘C |
|---|---|
| A | -112 |
| B | -6.3 |
Explain why substances with simple molecular structures have low boiling points.
Suggest why the boiling point of B is higher than the boiling point of A.
Substance B has the empirical formula CH2\text{CH}_2CH2 and an MrM_rMr value of 56. Determine the molecular formula of substance B.
Substance W is also covalently bonded, but its structure is different from that of A and B. It has a boiling point of 2230 ∘C2230\ ^\circ\text{C}2230 ∘C.
Explain, in terms of its structure, why W has such a high boiling point.
