4CH1/2CR — June 2026 (Edexcel IGCSE Chemistry): Past Paper

This question is about elements, compounds and mixtures.

Name the element that burns with a lilac flame.

Name the technique used to separate a mixture of liquids with different boiling points.

The box gives the names of some substances. air helium gallium mercury sulfur dioxide Choose substances from the box to answer these questions.

Identify the substance that is a mixture.

Identify the substance in Group 3 of the Periodic Table.

Explain why hydrogen chloride is a compound.

This question is about aluminium.

Why does solid aluminium conduct electricity?

Explain why aluminium is malleable.

Aluminium is extracted from aluminium oxide by electrolysis. The diagram shows the electrolysis of aluminium oxide. + – positive electrode negative electrode molten aluminium oxide molten aluminium steel tank

Why is aluminium not extracted by heating aluminium oxide with carbon?

Aluminium is formed at the negative electrode. Name the product formed at the positive electrode.

Suggest why the electrolysis of aluminium oxide is expensive.

Aluminium is used to make cans for drinks because it is malleable. Give another reason why aluminium is used to make cans for drinks.

This question is about the solubility of salts.

State what is meant by the term saturated solution.

The graph shows the solubilities of sodium chloride and potassium chloride at different temperatures. 55 potassium chloride 45 sodium chloride Solubility in g per 100 g of water 0 20 40 60 80 100 Temperature in C

Deduce the temperature at which sodium chloride and potassium chloride have the same solubility. temperature = °C

A saturated solution of potassium chloride in 100 g of water is cooled from 80 °C to 60 °C. Determine the mass, in grams, of potassium chloride that crystallises. mass = g

A student uses this apparatus to determine the solubility of potassium nitrate in water. thermometer water potassium nitrate beaker of hot water heat This is the student’s method. Step 1 add 6.2 g of potassium nitrate to a boiling tube Step 2 add 20 cm³ of water to the boiling tube Step 3 place the boiling tube in a beaker of water Step 4 heat the beaker gently, stirring the mixture in the boiling tube continuously until the potassium nitrate dissolves Step 5 remove the boiling tube from the beaker and allow the mixture to cool Step 6 record the temperature at which crystals start to form in the boiling tube

Name a piece of apparatus that the student could use in step 2 to measure 20 cm³ of water.

Give a reason why the student uses a beaker of hot water in step 3, rather than directly heating the boiling tube with a Bunsen burner.

In step 6, crystals start to form at 32 °C. Calculate the solubility of the solid, in g per 100 g of water, at 32 °C. [1.0 cm³ of pure water has a mass of 1.0 g] solubility = g per 100 g of water

The table gives some properties of the halogens fluorine, chlorine, bromine and iodine

Complete the table by giving the predicted properties of astatine.

A sample of fluorine contains two isotopes.

Describe, in terms of sub-atomic particles, what is meant by the term isotopes.

The two isotopes in this sample of fluorine are 189 F and 199 F The relative atomic mass (Ar) of the sample of fluorine is 18.998 Explain the relative abundances of the two isotopes. You do not need to do a calculation.

A student is given colourless solutions of chlorine and sodium bromide. Describe how the student can use these two solutions to show that chlorine is more reactive than bromine.

Explain why chlorine is more reactive than bromine. Refer to the atomic structures of chlorine and bromine in your answer.

This question is about alcohols.

Give two conditions needed for the production of ethanol by the fermentation of glucose. 1 2

A student uses this apparatus to find the molar enthalpy change, ΔH, for the combustion of propanol, C₃H₇OH thermometer copper can water spirit burner propanol

These are the student’s results. mass of water 125 g initial temperature of water 19.5 °C maximum temperature of water 52.8 °C Calculate the heat energy change, Q, in joules. [for water, c = 4.2 J / g / °C] Q = J

In a different experiment, the student burns 0.75 g of propanol. The heat energy change for this experiment is 19 500 J. Calculate the molar enthalpy change, ΔH, in kJ / mol. Include a sign in your answer. [for propanol, Mr = 60] ΔH = kJ / mol

This is the equation for the combustion of ethanol. C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O

Explain, in terms of bonds broken and bonds made, why this reaction is exothermic.

Draw an energy level diagram for this reaction. You should show ΔH as a single-headed arrow. Energy

This question is about sugars.

Sugar A has this percentage composition by mass. C = 44.7% H = 7.5% O = 47.8% Determine the empirical formula of sugar A. [Ar values: C = 12 H=1 O = 16] empirical formula =

A 5.00 cm³ sample of blood contains 0.00510 g of glucose, C₆H₁₂O₆ Calculate the concentration, in mol / dm³, of glucose in this sample. Give your answer to three significant figures. [1 dm³ = 1000 cm³] [for C₆H₁₂O₆ Mr = 180] concentration = mol / dm³

This equation represents the complete combustion of 1 mol of sugar B. B + y O₂ → 12CO₂ + zH₂O 8.55 g of sugar B is burned, producing 7200 cm³ of carbon dioxide at rtp. Use the equation to calculate the Mr of sugar B. [one mole of any gas occupies 24 000 cm³ at rtp] Mr =

This question is about nitric acid. This is the equation for a reaction that occurs in the manufacture of nitric acid. 4NH₃(g) + 5O₂(g) ⇌ 4NO(g) + 6H₂O(g) ΔH = –900 kJ / mol After several hours in a closed system, this reaction reaches dynamic equilibrium.

Give the meaning of the symbol ⇌

State what is meant by the term dynamic equilibrium.

Typical conditions for this reaction are a temperature of 800 °C and a pressure of 10 atm.

Explain the effects on rate of reaction and yield of products if the temperature is changed to 1000 °C but the pressure is kept at 10 atm. rate of reaction yield of products

Lowering the pressure would increase the yield of products. Give a reason why a lower pressure is not used.

A student does a titration using dilute nitric acid and a solution of sodium hydroxide with a known concentration. These are the first four steps in the student’s method. • add 25.0 cm³ of nitric acid to a conical flask • add sodium hydroxide solution to a burette and record the initial volume • add a few drops of methyl orange indicator to the flask • use the burette to add sodium hydroxide solution to the flask until the indicator changes colour Describe how the student could modify their method to obtain an accurate value for the volume of sodium hydroxide solution needed to neutralise 25.0 cm³ of nitric acid.