OCR GCSE Chemistry A (Gateway) Paper 4 Higher June 2025 question paper J248/04

Which row in the table shows the change in the percentage of each gas in the Earth’s atmosphere today compared to the Earth’s early atmosphere?

An iron nail is left in a test tube containing water.

The iron nail rusts.

Which graph shows how the mass of the iron nail changes?

The alkanes are a homologous series of molecules.

Which statement about different alkane molecules is correct ?

A The molecular formula of the molecules differs by CH₃.

B The molecules all contain a double bond.

C The molecules all have the same general formula.

D The molecules all have the same physical properties.

The theoretical yield of a product in a reaction is 71 g.

The actual yield is 60 g.

What is the percentage yield ?

A 15.5%

B 18.3%

C 84.5%

D 118.3%

Which type of bond is found in butene?

A Covalent

B Electrostatic

C Ionic

D Metallic

What is a disadvantage of a hydrogen/oxygen fuel cell?

A Electricity is generated directly from the reaction.

B Greenhouse gases are not produced.

C Hydrogen gas is produced from hydrocarbons.

D There are no moving parts.

Nitrogen reacts with hydrogen to make ammonia.

What is the volume of ammonia made from 366 cm³ of hydrogen?

183 cm³ A

244 cm³ B

549 cm³ C

732 cm³ D

What is the correct equation for the complete combustion of butane?

Why do Group 1 metals become more reactive down the group?

A There is a stronger attraction between the outer electron and the nucleus.

B There is less shielding.

C The outer electron gets closer to the nucleus.

D The outer electron is lost more easily.

Potash alum, KAl (SO₄)₂, is a chemical compound.

What is the test to identify the Group 1 metal in potash alum?

A A flame test gives a lilac flame.

B A white precipitate is made when barium chloride solution is added.

C A white precipitate is made when a few drops of sodium hydroxide solution are added.

D Damp red litmus paper turns blue.

The equation shows one stage in the extraction of the metal titanium, Ti.

Which row in the table shows what is oxidised and what is reduced?

The reaction between sulfur dioxide gas and oxygen gas reaches equilibrium in a sealed container.

The reaction is exothermic.

Which conditions will move the position of equilibrium to the left ?

A student investigates the rate of the reaction between zinc and an excess of hydrochloric acid.

The diagram shows the equipment the student uses.

The student has made a mistake setting up the delivery tube in their experiment.

Describe the mistake and the problem this will cause.

Mistake........

Problem........

The student sets up the experiment correctly.

They measure the volume of gas every 20 seconds.

The graph shows their results.

Calculate the mean rate of reaction between 0 seconds and 60 seconds.

Use the graph and the equation:

Give the units for your answer.

The student repeats the experiment.

They use the same mass of zinc, but in smaller pieces.

Draw a line on the graph to show the student’s results.

The reaction is faster when more concentrated hydrochloric acid is used.

Explain why.

Ammonia is made from nitrogen and hydrogen in the Haber process.

The word equation for the reaction is:

A catalyst is used in the Haber process.

Explain how the catalyst speeds up the reaction.

Ammonia is used in the manufacture of fertilisers.

NPK fertilisers contain the essential elements nitrogen, phosphorus, and potassium.

The table shows the percentages of nitrogen, phosphorus, and potassium in four different fertilisers.

Plants do not grow well if they get too little of these essential elements because:

• too little nitrogen can cause yellow leaves

• too little phosphorus can cause poor root growth

• too little potassium can cause poor fruit growth.

A farmer buys a 25 kg bag of fertiliser C.

Calculate the mass of potassium in the bag of fertiliser.

Fertilisers are made in industry using a continuous process.

Fertilisers can be made in a school laboratory using a batch process.

State one advantage of using a continuous process.

A life-cycle assessment is an analysis of the overall environmental impact that a product may have throughout its lifetime.

The life-cycle assessment is broken down into four main stages.

The first stage is looking at obtaining the raw materials.

State two other stages in a life-cycle assessment.

A company does a life-cycle assessment to investigate three possible materials for making a single-use takeaway food container.

The table gives some of the information the company uses.

Suggest which material the company should use to make the food container.

Explain your answer using information from the table.

Material........

Explanation........

The displayed formulae of molecules X and Y are shown in Fig. 19.1.

Fig. 19.1

State the name of the functional group in molecule X and molecule Y.

Molecule X........

Molecule Y........

Polyester is a condensation polymer.

Nylon is also a condensation polymer.

Nylon can be made in the laboratory using two solutions, A and B, as shown in Fig. 19.3.

Solution A is poured into a beaker.

Solution B is carefully poured on top of solution A to minimise mixing.

Fig. 19.3

State where the nylon forms and describe how the nylon is removed from the beaker.

The nylon forms........

The nylon is removed from the beaker by........

A naturally occurring polymer is made by combining monomers called nucleotides.

State the name of this natural polymer.

A student plans a titration experiment to find the concentration of a solution of sulfuric acid.

This is their method:

• Fill the burette with dilute sulfuric acid.

• Add 25.0 cm³ of 0.50 mol / dm³ sodium hydroxide solution to a conical flask.

• Add 5 drops of indicator to the sodium hydroxide solution.

• Add the dilute sulfuric acid to the sodium hydroxide solution until the indicator changes colour.

• Repeat the titration.

(a) State the piece of apparatus the student should use to accurately measure the 25.0 cm³ of (i) sodium hydroxide solution.

State a suitable indicator for the student to use in the titration.

Suggest an improvement to the student’s method.

The reading at the start of the rough titration is 0.0 cm³. (b)

At the end of the rough titration the student reads the volume of dilute sulfuric acid added from the burette.

What is the volume of dilute sulfuric acid added?

Give your answer to 2 decimal places.

After the rough titration the student repeats the experiment five more times.

The table shows their results.

The student calculated that the mean of these results was 24.50 cm³.

Explain why.

Use data from the table.

The equation for the reaction in the student’s titration is

They used 25.0 cm³ of 0.40 mol / dm³ sodium hydroxide solution and 24.50 cm³ of dilute sulfuric acid.

Calculate the concentration of the dilute sulfuric acid in mol / dm³.

Give your answer to 2 significant figures.

Concentration of dilute sulfuric acid =........ mol / dm³

* A teacher finds an unlabelled beaker containing a white solid.

They know that the solid is one of the following:

• lithium bromide

• lithium iodide

• sodium bromide

• sodium carbonate.

Plan a series of experiments the teacher can do to identify the white solid.

Include the reactants and apparatus used and the results of each experiment.

Instrumental methods of analysis can be used to analyse chemical substances.

State two advantages of instrumental methods of analysis.

Chlorine, Cl₂, reacts with lithium bromide, LiBr.

Write the balanced symbol equation for the reaction.

Iodine, I₂, does not react with lithium bromide.

Explain why.

Copper ore can be obtained by quarrying.

Copper metal is then extracted by heating the copper ore in a furnace.

One type of copper ore contains copper oxide.

The copper oxide is heated with carbon.

Write the balanced symbol equation for this reaction.

Scientists have developed methods of extracting copper from ores that contain a low percentage of copper compounds.

Suggest two reasons why scientists have developed these methods.

Metals can also be extracted from their metal oxide by reduction with hydrogen.

Element X is a metal.

Explain how the equation shows that the metal oxide is reduced.

The sum of the relative formula masses (M_r) of the reactants is 149.9.

Identify element X.

Use the Periodic Table.

Relative atomic mass (A_r): H = 1.0 O = 16.0

In the last 75 years there has been an increase in both:

• the world population

• the concentration of carbon dioxide in the atmosphere.

Why may the increase in the world population have caused the increase in the concentration of carbon dioxide in the atmosphere?

State one possible problem associated with an increase in the concentration of carbon dioxide in the atmosphere.