0620/42_Summer_2023_Q1
(a) State which of the oxides, A to H, is responsible for acid rain.
(b) State which of the oxides, A to H, has a giant covalent structure.
(c) State which of the oxides, A to H, is a reducing agent in the blast furnace.
(d) State which of the oxides, A to H, is the main constituent of bauxite.
(e) State which of the oxides, A to H, is the main impurity in iron ore.
(f) State which of the oxides, A to H, can be reduced by heating with copper.
0620/42_Summer_2023_Q2
(a) State the name given to Group VII elements.
(b) Explain why Group VII elements have similar chemical properties.
(c) Complete Table 2.1 to show the colour and state at r.t.p. of some Group VII elements.
\begin{align}
\begin{aligned}
&\text { Table } 2.1\\
&\begin{array}{|c|c|c|}
\hline \text { element } & \text { colour } & \text { state at r.t.p. } \\
\hline \text { fluorine } & \text { pale yellow } & \\
\hline \text { chlorine } & & \\
\hline \text { bromine } & & \text { liquid } \\
\hline
\end{array}
\end{aligned}
\end{align}
(d) Bromine has two naturally occurring isotopes, ⁷⁹Br and ⁸¹Br.
(i) State the term given to the numbers 79 and 81 in these isotopes of bromine.
(ii) Complete Table 2.2 to show the number of protons, neutrons and electrons in the atom and ion of bromine shown.
\begin{align}
\begin{aligned}
&\text { Table } 2.2\\
&
\end{aligned}
\end{align}
(iii) Table 2.3 shows the relative abundances of the two naturally occurring isotopes of bromine.
\begin{align}
\begin{aligned}
&\text { Table } 2.3\\
&\begin{array}{|l|c|c|}
\hline \text { isotope } & { }^{79} \mathrm{Br} & { }^{81} \mathrm{Br} \\
\hline \text { relative abundance } & 55 \% & 45 \% \\
\hline
\end{array}
\end{aligned}
\end{align}
Calculate the relative atomic mass of bromine to one decimal place.
(e) Chlorine displaces bromine from aqueous potassium bromide but does not displace fluorine from aqueous sodium fluoride.
(i) Write the symbol equation for the reaction between chlorine and aqueous potassium bromide.
(ii) State why chlorine does not displace fluorine from aqueous sodium fluoride.
(f) Aqueous silver nitrate is a colourless solution containing Ag⁺(aq) ions.
(i) Describe what is seen when aqueous silver nitrate is added to aqueous sodium chloride.
(ii) Write the ionic equation for the reaction between aqueous silver nitrate and aqueous sodium chloride. Include state symbols.
0620/42_Summer_2023_Q3
(a) State the name of the process used to manufacture sulfuric acid.
(b) Part of the manufacture of sulfuric acid involves converting sulfur dioxide to sulfur trioxide.
(i) Describe two methods by which sulfur dioxide is obtained.
The conversion of sulfur dioxide to sulfur trioxide is a reversible reaction which can reach equilibrium.
(ii) State two features of an equilibrium.
(iii) State the typical conditions and name the catalyst used in the conversion of sulfur dioxide to sulfur trioxide.
(iv) Complete Table 3.1 to show the effect, if any, when the following changes are applied to the conversion of sulfur dioxide to sulfur trioxide.
\begin{align}
2 \mathrm{SO}_2(\mathrm{~g})+\mathrm{O}_2(\mathrm{~g}) \rightleftharpoons 2 \mathrm{SO}_3(\mathrm{~g})
\end{align}
The forward reaction is exothermic.
Only use the words increases, decreases or no change.
\begin{align}
\begin{aligned}
&\text { Table } 3.1\\
&\begin{array}{|c|c|c|}
\hline \text { change } & \begin{array}{c}
\text { effect on the rate of } \\
\text { the forward reaction }
\end{array} & \begin{array}{c}
\text { effect on the concentration } \\
\text { of } \mathrm{SO}_3(\mathrm{~g}) \text { at equilibrium }
\end{array} \\
\hline \text { temperature decreases } & \text { decreases } & \\
\hline \text { pressure increases } & & \\
\hline \text { no catalyst } & \text { decreases } & \\
\hline
\end{array}
\end{aligned}
\end{align}
(v) Explain in terms of collision theory why reducing the temperature decreases the rate of the forward reaction.
(c) Sulfuric acid contains SO₄²⁻ ions.
The oxidation number of O atoms in SO₄²⁻ ions is –2. Determine the oxidation number of S atoms in SO₄²⁻ ions.
Show your working.
0620/42_Summer_2023_Q4
(a) State what is meant by the term base.
(b) State the term given to a base which dissolves to form an aqueous solution.
(c) State the color of thymolphthalein in NaOH(aq).
(d) Complete the word equation for the reaction of NaOH(aq) with ammonium chloride.
(e) Some metal oxides react with NaOH(aq).
(i) State the term given to metal oxides which react with bases such as NaOH(aq).
(ii) Name a metal oxide which reacts with NaOH(aq).
(f) Ethanoic acid, CH₃COOH, is a weak acid.
(i) Complete the dot-and-cross diagram in Fig. 4.1 of a molecule of ethanoic acid.
(ii) Suggest the pH of dilute ethanoic acid.
(iii) Complete the symbol equation to show the dissociation of ethanoic acid.
(g) In a titration, 25.0 cm³ of 0.0800 mol/dm³ aqueous potassium hydroxide, KOH(aq), is neutralized by 20.0 cm³ of dilute sulfuric acid, H₂SO₄(aq).
\begin{align}
2 \mathrm{KOH}(\mathrm{aq})+\mathrm{H}_2 \mathrm{SO}_4(\mathrm{aq}) \rightarrow \mathrm{K}_2 \mathrm{SO}_4(\mathrm{aq})+2 \mathrm{H}_2 \mathrm{O}(\mathrm{l})
\end{align}
Calculate the concentration of \(\mathrm{H}_2 \mathrm{SO}_4\), in \(\mathrm{g} / \mathrm{dm}^3\) using the following steps.
(i) Calculate the concentration of H₂SO₄, in g/dm³ using the following steps.
• Calculate the number of moles of KOH used.
• Determine the number of moles of H₂SO₄ which react with the KOH.
• Calculate the concentration of H₂SO₄ in mol/dm³.
• Calculate the concentration of H₂SO₄ in g/dm³.
0620/42_Summer_2023_Q5
When a molecule of propane, C₃H₈, reacts with chlorine in the presence of ultraviolet light, one atom of hydrogen is replaced by one atom of chlorine.
(i) State the term given to reactions in which one atom in an alkane is replaced by another atom.
(ii) State the purpose of ultraviolet light in this reaction.
(iii) State the term given to any reaction which requires ultraviolet light.
(iv) Write the symbol equation for the reaction between propane and chlorine.
A molecule of propene, C₃H₆, is unsaturated and will react with chlorine at room temperature.
(i) State why propene is an unsaturated molecule.
(ii) Give the structural formula of the product of this reaction.
Propene undergoes addition reactions with steam. There are two possible products, A and B.
Draw the displayed formula and name each product.
displayed formula of product A
name of product A
displayed formula of product B
name of product B
0620/42_Summer_2023_Q6
(a) Name the ester formed when butanoic acid, CH₃CH₂CH₂COOH, reacts with ethanol, CH₃CH₂OH.
(b) Identify the other product formed in this reaction.
(c) Deduce the empirical formula of the ester formed.
(d) PET is a polyester. Part of the structure of PET is shown in Fig. 6.1.
(i) Circle one repeat unit of this polymer.
(ii) Draw the structures of the monomers which make up PET. Draw the functional groups using displayed formulae.
(iii) State the type of polymerisation used in making PET.
0620/42_Winter_2023_Q1
(a) State which of the atoms or ions, A to G, could be a noble gas atom.
(b) State which of the atoms or ions, A to G, could be an atom of an element in Group VI.
(c) State which of the atoms or ions, A to G, could be an atom with an atomic number of 14.
(d) State which of the atoms or ions, A to G, could be atoms from the same group.
(e) State which of the atoms or ions, A to G, could be a halogen atom.
(f) State which of the atoms or ions, A to G, could be an atom of an element which is a good conductor of electricity.
(g) State which of the atoms or ions, A to G, could be a stable ion of a Group V element.