Edexcel GCSE Combined Science Paper 4: Chemistry 2 Foundation June 2025 question paper 1SC0/2CF

The elements in group 7 of the periodic table are called the halogens.

Give the symbol of the element astatine.

Use the periodic table to help you.

What is the colour of chlorine gas at room temperature?

Damp blue litmus paper can be used to test for chlorine gas.

Use words from the box to complete the sentences.

When damp blue litmus paper is added to chlorine gas there are two colour changes.

The damp blue litmus paper changes from blue to_........ .

The colour of the litmus paper then changes to_........ .

Figure 1 shows the atomic number and boiling point of some of the halogens.

Describe the trend in the boiling points of the first three halogens in Figure 1.

Using the information in Figure 1, predict the boiling point of iodine.

Write your prediction on the answer line below.

A student investigates the temperature change when 10 g of solid magnesium chloride is dissolved in 100 cm³ of water.

Figure 2 shows the apparatus the student uses.

Name the piece of apparatus labelled X in Figure 2.

The student carries out the following steps

step 1 measure the initial temperature of the water in the beaker

step 2 add the magnesium chloride

step 3 stir the mixture

step 4 record the new temperature.

State why the mixture is stirred in step 3.

State two ways the apparatus could be changed to reduce the heat energy lost during the investigation.

The student carries out the experiment three times.

Figure 3 shows the results.

Calculate the mean temperature change for this investigation.

Explain, using the information in Figure 3, the type of reaction that occurs when magnesium chloride dissolves in water.

Which gas made up the greatest proportion of the Earth’s early atmosphere?

Figure 4 shows the composition by volume of the Earth’s atmosphere today.

Give the name of the gas in Earth’s atmosphere today that makes up the largest proportion.

Using the information in Figure 4, calculate the percentage of argon and other gases in the Earth’s atmosphere today.

The percentage of oxygen in air can be measured using the apparatus shown in Figure 5.

The oxygen in the air reacts with the heated zinc.

Explain one change that would be seen during the reaction.

Name the product formed when the zinc reacts with oxygen in this experiment.

Figure 6 shows the electron configuration of an argon atom.

State why argon is unreactive.

Argon makes up 0.93% of the Earth’s atmosphere today.

Calculate the volume of argon, in cm³, in 4000 cm³ of air.

Lithium is an alkali metal.

State which group of the periodic table contains the alkali metals.

Which of the following is a property of lithium?

A teacher adds a small piece of lithium to water containing universal indicator.

The universal indicator changes colour.

State the colour change shown by the universal indicator.

When lithium is added to water, lithium hydroxide and a gas are produced.

What is the name of the gas produced in this reaction?

Lithium hydroxide contains lithium ions, Li⁺.

Describe how a lithium atom becomes a lithium ion.

Calculate the percentage by mass of hydrogen in lithium hydroxide, LiOH.

(relative atomic masses: Li = 7, O = 16, H = 1.0)

When solutions P and Q are mixed together, a purple mixture forms. This mixture slowly becomes colourless.

A student pours 25 cm³ of solution P into a conical flask and then adds 25 cm³ of solution Q.

The student uses a beaker to measure out these volumes.

Name a piece of apparatus that could be used to measure these volumes more accurately.

The student investigates this reaction using the apparatus shown in Figure 7. The student measures the time taken for the cross to become visible. The experiment is repeated at different temperatures.

Figure 8 shows the results.

The concentrations of the solutions are kept constant in each experiment.

State one other variable that should be kept constant.

State, and explain in terms of particles, how the time taken for the cross to become visible would change if a temperature of 80 °C was used.

The concentration of solution Q is 26.8 g dm^–3.

Calculate the mass of solid Q present in 25 cm³ of solution Q.

The student repeats the experiment at 20 °C, with the addition of a catalyst.

Explain how the addition of a catalyst will affect the rate of reaction.

Hydrogen peroxide, H₂O₂, decomposes into oxygen and water.

A catalyst can be used to increase the rate of this reaction.

Use a word or phrase from the box to complete the sentence about the mass of the catalyst in a reaction.

During a reaction, the mass of a catalyst_........ .

Complete the balanced equation for this reaction and add the missing state symbol.

Crude oil is a mixture of hydrocarbons.

The majority of hydrocarbons in crude oil belong to one homologous series.

Give the name of this series.

When hydrocarbons undergo combustion, water is produced.

Draw a dot and cross diagram of a molecule of water.

One compound in crude oil contains 0.96 g of carbon atoms combined with 0.32 g of hydrogen atoms.

Calculate the empirical formula of this compound.

(relative atomic masses: C = 12, H = 1.0)

*(d) Crude oil is separated into useful products called fractions using fractional distillation.

Figure 9 shows a fractional distillation column and the fractions kerosene and fuel oil.

Kerosene and fuel oil have different uses depending on their properties.

Describe the properties and uses of kerosene and fuel oil. Include in your answer

• the difference in boiling point

• the difference in viscosity

• the difference in ease of ignition

• their uses and how fuel oil can be converted into kerosene.