OCR GCSE Chemistry A (Gateway) Paper 3 Higher June 2022 question paper J248/03

Which particle model diagram shows evaporation?

The radius of a helium atom is 0.14 nm.

What is the radius of a helium atom in metres?

0.14 × 10^–10 m A

1.4 × 10^–10 m B

1.4 × 10^–9 m C

14 × 10^–9 m D

A Group 1 element reacts with a Group 7 element, so that both elements have a full outer shell of electrons. The table shows what happens to both elements during the reaction.

Which row is correct?

The diagram of an atom shows that electrons occupy shells around the nucleus.

Which scientist proposed this atomic model?

A Bohr

B Dalton

C J. J. Thomson

D Mendeleev

What is an oxidising agent?

A A species that causes oxidation but does not get oxidised or reduced itself.

B A species that is oxidised and reduced.

C A species that is oxidised, while another species in the reaction is reduced.

D A species that is reduced, while another species in the reaction is oxidised.

Which statement about carbon allotropes is correct?

A Buckminsterfullerene is a type of carbon nanotube.

B Carbon atoms in diamond and graphite form 4 covalent bonds.

C Graphene and graphite both have carbon atoms arranged in layers.

D Strong covalent bonds cause diamond to have a high melting point.

A student wants to separate substances by filtration.

They write a method for the experiment but not in the correct order as shown.

1. Pour the mixture through the funnel into the conical flask.

2. Fold the filter paper.

3. Collect the filtrate in the conical flask.

4. Put the filter paper into the funnel.

5. Collect any insoluble substances on the filter paper.

What is the correct method order for this experiment?

A 1, 2, 4, 5, 3

B 2, 1, 4, 5, 3

C 2, 4, 1, 5, 3

D 4, 2, 5, 3, 1

Molten sodium chloride can be electrolysed.

What is the correct half equation for the reaction at the negative electrode (cathode)?

Why do some polymers have different flexibilities?

A They are more flexible because they contain covalent bonds.

B They are more flexible as they do not have strong cross-links.

C They are more rigid because they contain ionic bonds.

D They are more rigid because they have weak intermolecular forces.

A student investigates an endothermic reaction. Their results are shown in the table.

Which statement is correct for an endothermic reaction?

A scientist investigates the melting point of some substances that may contain paracetamol as shown in the table.

The melting point of pure paracetamol is 169 °C.

Which statement about the results is correct?

A All of the substances contain paracetamol.

B Substance 2 does not contain paracetamol.

C Substance 3 is pure paracetamol.

D Substance 4 is impure paracetamol.

A sample of propanoic acid, C₃H₆O₂, is made using an isotope of hydrogen, called deuterium.

The relative atomic mass of deuterium is 2.0.

What is the relative molecular mass, M_r, of propanoic acid when deuterium atoms replace all the hydrogen atoms?

A 68.0

B 74.0

C 80.0

D 86.0

Which statement about the bonding in magnesium oxide is correct?

A There are strong covalent bonds between atoms.

B There are strong covalent bonds between ions.

C There are strong electrostatic forces between atoms.

D There are strong electrostatic forces between ions.

An alloy that contains silver, copper and tin has 96% tin and 2.5% copper. The rest is silver.

What is the mass of silver in 12.0 g of the alloy?

A 0.18 g

B 0.3 g

C 1.8 g

D 3.0 g

The diagram shows a ball and stick model for ethene, C₂H₄.

Which statements about this ball and stick model of ethene are correct?

Tick (✓) two boxes.

Molecules can be drawn using dot and cross diagrams.

Complete the dot and cross diagram for bromine, Br₂.

Show the electrons in the outer shells only.

At room temperature, ethene is a gas and bromine is a liquid.

Use the particle model to describe two differences between the movement or arrangement of the particles in ethene and the particles in bromine.

Ethene reacts with bromine to make a product.

The relative formula mass of the product is 187.8.

There are 2 carbon atoms and 4 hydrogen atoms in the product.

Calculate how many bromine atoms are in the product.

A student has a sample of a liquid.

State a method the student uses to find out if the sample is pure.

The student finds out that the sample is impure.

The sample contains hexane, C₆H₁₄, and cyclohexane, C₆H₁₂.

What is the empirical formula of hexane?

The boiling point of hexane is lower than the boiling point of cyclohexane.

Describe a method the student could use to obtain a sample of pure hexane from the mixture of cyclohexane and hexane.

You can include a labelled diagram in your answer.

The student obtains 12.0 g of hexane from 15.2 g of the mixture of hexane and cyclohexane.

Calculate the percentage of hexane obtained.

Give your answer to 2 significant figures.

Hexane reacts with oxygen in a combustion reaction.

Complete the balanced symbol equation for this reaction.

A scientist investigates three solutions, A, B and C. They want to find out if the solutions are acids or alkalis. They don’t have any universal indicator or a pH probe.

• In test 1, they try to neutralise the solutions by adding 25 cm³ of dilute hydrochloric acid to 25 cm³ of each solution.

• In test 2, they add 1.0 g of magnesium carbonate to 25 cm³ of each solution.

The table shows the scientist’s observations.

* Use the observations from both test 1 and test 2 to state which solutions are acids and which solutions are alkalis.

Explain your answer.

The graphs show the titration curves for three different experiments.

Draw three lines to connect each titration curve with its correct description.

Write the ionic symbol equation for a neutralisation reaction.

Include state symbols.

Draw a line of best fit on the graph.

What is the volume of hydrogen gas given off after 23 minutes?

Which electrode is hydrogen gas given off at?

State the name of the product made at the other electrode.

A student repeats the teacher’s experiment with aqueous copper sulfate, CuSO₄. The student finds that no hydrogen gas is given off.

Explain why hydrogen gas is given off in the electrolysis of aqueous NaC l, but not in the electrolysis of aqueous CuSO₄.

In the electrolysis of aqueous copper sulfate, copper is also made.

The teacher sets up an experiment to measure the volume of oxygen gas made.

Explain how the student could change the experiment to measure the amount of copper formed.

Three cakes each contain a different brand of food colouring dye.

• The colour is the same in each cake, but the taste in one is different.

• The cakes’ baker thinks it is because of the food colouring dye.

The baker compares the food colouring dyes that were used in the three different cakes using thin layer chromatography. The chromatogram is shown in Fig. 20.1.

Fig. 20.1

Calculate the R_f value of the blue spot in the dye in cake 3.

Give your answer to 2 significant figures.

Which of the cakes would you expect to taste the same?

Explain your answer using data from Fig. 20.1.

The baker thinks the dyes are mixtures where the substances are combined in exact amounts.

What is the name given to this type of mixture?

Brass is also a mixture of different substances combined in exact amounts.

What type of substance is brass?

Tick (✓) one box.

The student tests another dye. The chromatogram is shown in Fig. 20.2.

Fig. 20.2

What should the student change in their experiment to separate the blue and yellow spots?

Phosphorus can exist as P₄ molecules.

Phosphorus trichloride, PCl₃, is made in the reaction of phosphorus, P₄, and chlorine as shown in the equation.

A scientist starts the reaction with 2.0 mol of phosphorus, P₄.

Calculate the mass of 2.0 mol of phosphorus.

Calculate the maximum mass of phosphorus trichloride, PCl₃, that could be made from 2.0 mol of phosphorus, P₄.

The scientist reacts the 2.0 mol of phosphorus, P₄, with 866.2 g of chlorine, Cl₂.

Which is the limiting reactant ? Explain your answer.

Limiting reactant........

Explanation........

Complete the table.

Phosphorus trichloride

Phosphorus pentachloride

Phosphorus trifluoride

Explain your answer using information from the table.

The scientist thinks phosphorus trichloride is a giant covalent compound.

Explain why the scientist is incorrect.

Compounds that contain the element zinc, Zn, have many uses.

Calculate the mass of one atom of zinc.

The Avogadro constant is 6.02 × 10^–23.

Give your answer to 3 significant figures.

Zinc bromide is an ionic compound made from zinc ions, Zn²⁺, and bromide ions, Br^–. (b)

Construct a balanced ionic equation for the formation of zinc bromide.

Zinc bromide can conduct electricity when aqueous or molten, but not when solid.

Zinc metal can conduct electricity when solid.

Explain why.

Zinc bromide........

Zinc metal........

Zinc oxide, ZnO, is another compound containing zinc.

The table shows some information about four different zinc oxide particles.

Which particles are nanoparticles?

Tick (✓) two boxes.

A scientist wants to buy some zinc oxide particles to use in suncream. A large surface area to volume ratio is important.

Which particle, A, B, C or D, would be the most suitable for use in suncream?

Explain your answer.

Particle........

Explanation........