AQA GCSE Chemistry Paper 1 Higher June 2023 question paper 8462/1H

Discoveries in chemistry led to a better understanding of atomic structure.

Atoms were originally thought to be tiny spheres that could not be divided. The plum pudding model of the atom was then developed. Figure 1 represents the plum pudding model of the atom.

Describe the plum pudding model of the atom.

Atoms contain electrons, neutrons and protons. Write these three particles in order of their discovery.

Very few atoms of the element tennessine (Ts) have ever been identified. The atomic number of tennessine is 117

Predict the number of outer shell electrons in an atom of tennessine. Give one reason for your answer. Use the periodic table. Number of outer shell electrons

Tennessine was first identified by a small group of scientists in 2010. Suggest one reason why tennessine was not accepted as a new element by other scientists until 2015.

The discovery of isotopes explained why some relative atomic masses are not whole numbers. Element R has two isotopes. Table 1 shows the mass numbers and percentage abundances of the isotopes of element R.

Calculate the relative atomic mass (A_r) of element R. Give your answer to 1 decimal place.

This question is about temperature changes.

A student investigated the change in temperature of a solution when different masses of ammonium nitrate were dissolved in water. This is the method used.

1. Measure 200 cm³ of water into a polystyrene cup.

2. Measure the temperature of the water.

3. Add 4.0 g of ammonium nitrate to the water.

4. Stir the solution until all the ammonium nitrate has dissolved.

5. Measure the lowest temperature reached by the solution.

6. Repeat steps 1 to 5 with different masses of ammonium nitrate.

Give the independent variable and the dependent variable in the investigation. Independent variable Dependent variable

Table 2 shows the results.

Plot the data from Table 2 on Figure 2. Draw a line of best fit.

Determine the initial temperature of the water. You should extend your line of best fit on Figure 2.

How do the results show that dissolving ammonium nitrate in water is endothermic?

The student repeated the experiment three more times. Table 3 shows the results for 8.0 g of ammonium nitrate.

The student recorded the mean lowest temperature of the solution for 8.0 g of ammonium nitrate as 16.5 ± 0.3 ºC. Explain why the student included ± 0.3 ºC after the mean lowest temperature.

What type of error is shown by the results in Table 3 ? Tick (✓) one box.

This question is about making a soluble salt.

Plan a method to make pure, dry crystals of zinc chloride from zinc carbonate and a dilute acid.

Name two other substances that can each be reacted with a dilute acid to make zinc chloride. Do not refer to zinc carbonate in your answer.

This question is about hydrogen and compounds of hydrogen. Figure 3 shows the displayed formulae for the reaction between hydrogen and chlorine.

Figure 3

Table 4 shows the bond energies.

Which expression shows how to calculate the overall energy change for the reaction in Figure 3 ? Use Table 4. Tick (✓) one box.

The reaction between hydrogen and chlorine is exothermic.

Explain why this reaction releases energy to the surroundings.

Figure 4 shows part of a reaction profile for the reaction between hydrogen and chlorine. Complete the reaction profile in Figure 4. You should:

• label the activation energy

• label the overall energy change.

Draw a dot and cross diagram for a molecule of hydrogen chloride (HC l). Show the outer shell electrons only.

Figure 5 represents molecules of methane and of poly(ethene).

Methane is a gas at room temperature but poly(ethene) is a solid at room temperature.

Explain why methane and poly(ethene) exist in different states at room temperature.

This question is about acids and alkalis.

Ethanoic acid is a weak acid. What is meant by ‘weak acid’? Answer in terms of ionisation.

The concentration of an acid can be measured in mol/dm³. Which combination of changes increases the concentration of an acid? Tick (✓) one box.

The concentration of an acid can be determined by titration. An indicator is added to an alkali in a flask.

Name an indicator that can be used in this titration. Give the colour change of the indicator when acid from a burette is added to the alkali in the flask.

Sodium carbonate dissolves in water to produce an alkaline solution. Give the formula of the ion that makes a solution alkaline.

A student does a titration using sodium carbonate solution and nitric acid. The equation for the reaction is:

25.0 cm³ of 0.124 mol/dm³ sodium carbonate solution is neutralised by

Calculate the concentration of the nitric acid. Give your answer to 3 significant figures. You should calculate:

• the number of moles of sodium carbonate in 25.0 cm³ of the solution

• the number of moles of nitric acid in 23.6 cm³ of the nitric acid

• the concentration of the nitric acid in mol/dm³.

When hydrochloric acid dissolves in water, hydrogen ions (H⁺) and chloride ions (Cl⁻) are produced.

A solution of hydrochloric acid with pH 4.5 has a concentration of H⁺ ions of

What is the concentration of H⁺ ions in a solution of hydrochloric acid with pH 2.5?

Which element has atoms that have the same electronic structure as the chloride ion? Use the periodic table.

This question is about uses of metals in electrical wires. Electrical wires can be made from:

• aluminium

• copper

• silver.

Figure 6 shows three uses of electrical wires.

Table 5 shows information about the metals. The higher the value for electrical conductivity, the better the metal is at conducting electricity.

Evaluate the use of aluminium, copper and silver for the types of electrical wires shown in Figure 6. Use Table 5.

Describe how metals conduct electricity.

Electrical wires are usually made of pure metals and not alloys. This is because pure metals are better electrical conductors. Suggest why alloys do not conduct electricity as well as pure metals. Answer in terms of structure and bonding.

This question is about electrolysis.

Aluminium is manufactured by electrolysing a molten mixture of aluminium oxide

Complete the half equation for the reaction occurring at the negative electrode.

Cryolite contains Na⁺ ions as well as Al³⁺ ions. Suggest one reason why sodium is not a product of the electrolysis.

A student investigated the electrolysis of an aqueous solution of a different compound. Figure 7 shows the apparatus.

Hydrogen was produced at the negative electrode and oxygen was produced at the positive electrode.

Explain how oxygen was produced from water during the electrolysis of this aqueous solution.

The student compared the volumes of the two gases collected. How can the student change the apparatus in Figure 7 to compare the volumes of the two gases produced more accurately? Give one reason for your answer.

The overall equation for the reaction is:

What is the volume of oxygen produced when 20 cm³ of hydrogen has been produced?

Tick (✓) one box.

This question is about elements in the periodic table.

Argon has the atomic number 18 Explain why argon does not form compounds. Answer in terms of electrons.

Phosphorus (P) is the element below nitrogen in the periodic table. Predict the formula of the compound formed between phosphorus and hydrogen.

Tellurium is the element with atomic number 52 Predict whether tellurium reacts with metals. Explain your answer. Answer in terms of the position of tellurium in the periodic table.

Barium (Ba) is an element in Group 2 of the periodic table. Barium reacts with hydrochloric acid.

Suggest two observations that could be made when barium reacts with hydrochloric acid.

Write a balanced symbol equation for the reaction between barium and hydrochloric acid.

This question is about displacement reactions.

Iron is extracted from iron oxide by a displacement reaction with carbon. The equation for the reaction is:

Which substance in the equation is reduced? Give one reason for your answer. Answer in terms of oxygen.

Which expression shows how to calculate the mass of carbon needed to produce 1 mole of iron from iron oxide? Relative atomic mass (A_r): C = 12 Tick (✓) one box.

A student investigated displacement reactions of four different metals represented by A, B, C and D. A, B, C and D are not the actual chemical symbols for the metals. The student:

• added each metal to aqueous solutions of the metal nitrates

• observed whether a reaction took place.

Table 6 shows information about three of the reaction mixtures.

The ionic equation for Reaction 1 is:

Why is this a redox reaction?

Tick () one box.

Which of the four metals has the greatest tendency to form positive ions? Use Table 6. Tick (✓) one box.

The nitrate ion has the formula NO₃^– Which of the four metals could be aluminium? Explain your answer. Use Table 6.

Metal X is extracted from an oxide of metal X by reaction with hydrogen. The equation for the reaction is:

The percentage atom economy for obtaining metal X by this method is 77.3%. Calculate the relative atomic mass (A_r) of metal X. Relative atomic masses (A_r): H = 1 O = 16

This question is about titanium dioxide (TiO₂).

Self-cleaning windows are coated with a layer of nanoparticles of titanium dioxide. Titanium dioxide:

• helps sunlight break down dirt particles

• attracts water, so dirt is washed away by rain.

Nanoparticles of titanium dioxide are used instead of fine particles of titanium dioxide for coating self-cleaning windows. Suggest two reasons why.

Titanium is extracted from titanium dioxide in a two-stage process. The equation for the first stage in the process is:

Calculate the volume of chlorine gas needed to react completely with 100 kg of titanium dioxide. Relative atomic masses (A_r): O = 16 Ti = 48 The volume of one mole of gas = 24 dm³