Simple molecules and covalent bonds: past paper questions

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• Question 1May/June 2026, paper 21Structured5 marks

  Choose from the following compounds to answer the questions.

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• Question 4Oct/Nov 2025, paper 11Multiple choice1 markHas a diagram

  The structure of hydroxylamine, ${\mathrm{N}\mathrm{H}}_2\mathrm{O}\mathrm{H}$, is shown. Which row about hydroxylamine is correct?

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• Question 6Oct/Nov 2024, paper 11Multiple choice1 mark

  Which pair of molecules have the same number of electrons in covalent bonds?

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• Question 5May/June 2023, paper 11Multiple choice1 mark

  Ethane, ${\text{C}}_2{\text{H}}_6$, and ammonia, ${\text{NH}}_3$, are covalent compounds. The dot-and-cross diagrams of these compounds are shown. Which statements are correct?

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• Question 2May/June 2026, paper 21Structured12 marks

  Sodium azide, ${\mathrm{N}\mathrm{a}\mathrm{N}}_3$, decomposes when heated to make sodium and nitrogen. $$2{\mathrm{N}\mathrm{a}\mathrm{N}}_3(\mathrm{s})\to 2\mathrm{N}\mathrm{a}(\mathrm{s})+3{\mathrm{N}}_2(\mathrm{g})$$ A sample of $13.6\mathrm{g}$ of sodium azide is fully decomposed.

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• Question 6Oct/Nov 2025, paper 12Multiple choice1 markHas a diagram

  Which row is correct?

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• Question 2Oct/Nov 2024, paper 12Multiple choice1 markHas a diagram

  Substance X has a simple molecular structure and substance Y has a giant covalent structure. Which row is correct?

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• Question 5May/June 2023, paper 12Multiple choice1 mark

  Which molecule has the largest number of electrons involved in covalent bonds?

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• Question 2May/June 2026, paper 22Structured11 marks

  Potassium superoxide, ${\mathrm{K}\mathrm{O}}_2$, reacts with carbon dioxide to make potassium carbonate and oxygen.

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• Question 4Oct/Nov 2025, paper 21Structured9 marks

  Fluorine, chlorine, bromine and iodine are elements in Group VII. Bromine has a low boiling point. It is a liquid at room temperature.

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• Question 6Oct/Nov 2024, paper 21Structured10 marksHas a diagram

  Fig. 6.1 shows the structures of zinc sulfide and disulfur dichloride. Zinc sulfide has a structure similar to diamond. Explain why zinc sulfide does not conduct electricity.

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• Question 25May/June 2023, paper 12Multiple choice1 markHas a diagram

  The element phosphorus, P, is immediately below nitrogen in the Periodic Table. It forms an oxide with the empirical formula ${\mathrm{P}}_2{\mathrm{O}}_5$. From the position of phosphorus in the Periodic Table, the element is expected to be ......1......

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• Question 6Oct/Nov 2025, paper 21Structured9 marksHas a diagram

  This question is about an unsaturated hydrocarbon called ethyne. Fig. 6.1 shows the displayed formula of ethyne. $$\mathrm{H}-\mathrm{C}\equiv \mathrm{C}-\mathrm{H}$$ Fig. 6.1 Draw a dot-and-cross diagram to show the electronic arrangement in a molecule of ethyne.

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• Question 6Oct/Nov 2024, paper 22Structured9 marksHas a diagram

  Fig. 6.1 shows the structures of boron nitride and hydrazine. Boron nitride has a structure similar to diamond. Explain why boron nitride has a high melting point.

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• Question 7May/June 2023, paper 21Structured11 marksHas a diagram

  Methanol, propan-1-ol and propan-2-ol are alcohols. The displayed formulae of methanol and propan-1-ol are shown in Fig. 7.1. State the general formula of the homologous series of alcohols.

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• Question 4Oct/Nov 2025, paper 22Structured8 marks

  Fluorine, chlorine, bromine and iodine are elements in Group VII. Fluorine has a low boiling point. It is a gas at room temperature.

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• Question 16May/June 2024, paper 11Multiple choice1 markHas a diagram

  Silicon(IV) chloride, ${\mathrm{S}\mathrm{i}\mathrm{C}\mathrm{l}}_4$, boils at $58{}^{\circ }\mathrm{C}$. Which row shows the type of change when silicon(IV) chloride boils and the explanation?

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• Question 7May/June 2023, paper 22Structured10 marksHas a diagram

  Ethene, but-1-ene and but-2-ene are alkenes. The displayed formulae of ethene and but-1-ene are shown in Fig. 7.1. State the general formula of the homologous series of alkenes.

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• Question 6May/June 2025, paper 11Multiple choice1 markHas a diagram

  Magnesium reacts with oxygen to form magnesium oxide. $$2\mathrm{M}\mathrm{g}+{\mathrm{O}}_2\to 2\mathrm{M}\mathrm{g}\mathrm{O}$$ Which row is correct?

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• Question 5May/June 2024, paper 12Multiple choice1 mark

  Which molecule has only four electrons involved in covalent bonds?

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• Question 3May/June 2025, paper 21Structured9 marksHas a diagram

  The equation for the reaction between methane and chlorine is shown in Fig. 3.1. Fig. 3.1 State one condition for this reaction.

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• Question 6May/June 2024, paper 12Multiple choice1 markHas a diagram

  The melting points and boiling points of four compounds, W, X, Y and Z, are given in the table.

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• Question 3May/June 2025, paper 22Structured9 marksHas a diagram

  The equation for the reaction between ethene and bromine is shown in Fig. 3.1. Describe the observation when ethene gas is bubbled through aqueous bromine.

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• Question 2May/June 2024, paper 21Structured13 marksHas a diagram

  Calcium carbide, $\mathrm{C}\mathrm{a}{\mathrm{C}}_2$, reacts with water to form a flammable gas ethyne, ${\mathrm{C}}_2{\mathrm{H}}_2$, and calcium hydroxide. Construct the symbol equation for this reaction.

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• Question 2May/June 2024, paper 22Structured12 marksHas a diagram

  Aluminium carbide, ${\mathrm{A}\mathrm{l}}_4{\mathrm{C}}_3$, reacts with water to form methane, ${\mathrm{C}\mathrm{H}}_4$, and aluminium hydroxide. Construct the symbol equation for this reaction.

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