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Covalent bonding

Covalent bonding

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Question 11

Hydrogen fluoride is formed in the reaction between hydrogen and fluorine. The equation for the reaction is:

H2+F2→2HF \text{H}_2 + \text{F}_2 \rightarrow 2\text{HF} H2​+F2​→2HF
a.

Each molecule in this equation contains the same type of bonding. Name this type of chemical bonding.

[1]
b.

The covalent bonds inside a fluorine molecule are strong. Explain why the boiling point of fluorine is low.

[2]
c.

Explain how the two fluorine atoms in a fluorine molecule (F2\text{F}_2F2​) are held together.

[2]
d.

In a dot-and-cross diagram showing only the outer-shell electrons of a hydrogen fluoride (HF\text{HF}HF) molecule:

  1. State the number of shared electrons between the hydrogen and fluorine atoms.
  2. State the number of non-bonding (unshared) outer-shell electrons on the fluorine atom.
[2]
e.

Hydrogen bromide gas (HBr\text{HBr}HBr) dissolves in water to form solution X. Hydrogen bromide gas dissolves in methylbenzene to form solution Y. A student adds a piece of calcium carbonate to each solution. Explain why effervescence is observed with solution X but not with solution Y.

[4]
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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