Edexcel IGCSE Chemistry Chemistry Paper 1 June 2022 question paper 4CH1/1CR

The diagram represents an atom of an element.

Use numbers from the box to complete the table.

You may use each number once, more than once or not at all.

In terms of sub‑atomic particles, state a similarity and a difference for isotopes of the same element.

similarity

difference

This question is about apparatus used in the laboratory.

Complete the table by giving the name of each piece of apparatus and a unit used for the quantity it measures.

The diagram shows apparatus used to obtain pure water from sodium chloride solution by simple distillation.

Explain why it is necessary for water to flow continuously in and out of the apparatus.

Describe a chemical test to show that the sodium chloride solution contains chloride ions.

Describe a physical test to show that the liquid in the conical flask is pure water.

The diagram shows a chromatogram of the food dyes in four different food colourings, A, B, C and D.

Give the letter of the food colouring that contains three different food dyes.

Give the letters of the two food colourings that contain the same dye.

Using the scale on the diagram, determine the R_f value of the dye in food colouring C.

Give a reason why the dye in food colouring D moves the furthest from the start line.

Describe how a student could obtain a chromatogram similar to the one shown in the diagram.

The diagram shows the positions of some elements in part of the Periodic Table.

Na A l S C l

K Xe

Give the symbol of a metal from the diagram.

Give the symbol of an element from the diagram that forms an acidic oxide.

Give a similarity in the electron configurations of A l and I n.

Explain which element in the diagram is unreactive.

A teacher adds a small piece of sodium to a glass trough containing water and universal indicator.

The universal indicator changes colour.

The equation for the reaction is

Explain the final colour of the universal indicator.

The teacher repeats the experiment with potassium instead of sodium.

Give one similarity and one difference observed with potassium.

similarity

difference

The reaction with sodium produces 0.036 g of hydrogen gas.

One mole of hydrogen gas contains 6.010²³ molecules.

Calculate the number of molecules of hydrogen gas produced in the reaction with sodium.

Give your answer to two significant figures.

This question is about metal carbonates.

When heated, some metal carbonates decompose to form a metal oxide and carbon dioxide gas.

A student is given three solid metal carbonates, a timer, some limewater and this apparatus.

Describe a method the student can use to find out which metal carbonate decomposes fastest when heated.

A student is given a solid metal carbonate with the formula XCO₃

X represents the symbol of a Group 2 metal.

A student uses this apparatus to heat a sample of XCO₃ until it all decomposes.

The equation for the decomposition of XCO₃ is

The student records the mass of XCO₃ and the mass of carbon dioxide that escapes through the cotton wool plug.

These are the student’s results.

Give a reason why the student uses a cotton wool plug.

Calculate the amount, in mol, of carbon dioxide produced.

[for carbon dioxide M_r = 44]

Use the equation to determine the amount, in mol, of XCO₃ that decomposed.

Use the mass of XCO₃ and your answer to (b)(iii) to calculate the relative formula mass (M_r) of XCO₃

Use your answer to (b)(iv) and the Periodic Table on page 2 to determine the identity of the Group 2 metal X.

Show your working.

Silicon hydride (SiH₄) and silicon dioxide (SiO₂) both contain covalent bonds but they have different structures.

Describe the forces of attraction in a covalent bond.

Complete the diagram to show the outer shell electrons in a molecule of silicon hydride (SiH₄).

The diagram represents part of the structure of silicon dioxide (SiO₂).

State how the diagram shows that the atom labelled A is oxygen, not silicon.

Silicon hydride has a simple molecular structure.

Silicon dioxide has the same type of structure as diamond.

Explain why silicon dioxide has a much higher melting point than silicon hydride.

Refer to structure and bonding in your answer.

Silicon hydride reacts with oxygen to form silicon dioxide and water.

Write a chemical equation for the reaction between silicon hydride and oxygen.

The diagram shows some important conversion processes used in the oil industry.

Describe how kerosene is produced from crude oil in process 1.

C₁₂H₂₆ is present in kerosene.

In process 2, C₁₂H₂₆ is cracked to produce two molecules of ethene and one molecule of another hydrocarbon.

Complete the equation for the cracking of C₁₂H₂₆

Explain why cracking is a useful process in the oil industry.

This is the equation for one of the reactions that may occur during process 3.

H H

C l C l

What is the name of this type of reaction?

Explain why the disposal of polymers such as poly(chloroethene) is difficult.

This question is about exothermic reactions.

A student uses this apparatus to measure the temperature increase when an excess of zinc powder is added to copper(II) sulfate solution.

Complete the word equation for the reaction.

zinc + copper(II) sulfate _........ +_........

Give a reason why the student uses a polystyrene cup inside a glass beaker.

State why zinc reacts with copper(II) sulfate solution.

The temperature at the start of the reaction is 19.7C.

The temperature at the end of the reaction is 48.3C.

Calculate the heat energy change, in joules, for the reaction.

[for the mixture, c = 4.2 J/g/C]

The reaction between zinc and silver nitrate solution is exothermic.

A mass of 0.65 g of zinc is added to excess silver nitrate solution.

The heat energy change is 800 J.

Calculate the molar enthalpy change, Δ H, in kJ/mol.

Include a sign in your answer.

ΔH =_........ kJ/mol

This is the ionic equation for the reaction between zinc and silver nitrate solution.

Explain, in terms of electrons, why this is a redox reaction.

This question is about rates of reaction.

A student uses this method to investigate the rate of reaction between iron(III) nitrate solution and sodium thiosulfate solution.

• pour 50 cm³ of iron(III) nitrate solution into a conical flask

• add one drop of catalyst solution

• add 50 cm³ of sodium thiosulfate solution to the conical flask

• record the time for the mixture to become colourless

The student repeats the method using different catalysts and also with no catalyst.

The table shows the student’s results.

Explain which is the best catalyst for the reaction.

Explain how a catalyst increases the rate of a reaction.

The rate of a reaction can also be altered by changing the temperature or by changing the concentration of solutions.

Explain, using the particle collision theory, how increasing the temperature affects the rate of a reaction.

Explain why using a solution of a lower concentration decreases the rate of reaction.

A student investigates how the electrical conductivity changes as dilute sulfuric acid is added to barium hydroxide solution.

This is the student’s method.

Step 1 =$~dd=RMKM cm³ of barium hydroxide solution to a beaker

Step 2 measure the electrical conductivity of the solution

Step 3 =$~dd=NMKM cm³ of dilute sulfuric acid to the beaker

Step 4 stir the mixture

Step 5 measure the electrical conductivity of the mixture

Step 6 repeat steps 3 to 5 until a total of 100 cm3³ of dilute sulfuric acid has been added

The table shows the student’s results.

Name a piece of apparatus the student could use to add 10.0 cm³ of dilute sulfuric acid to the beaker.

Plot the student’s results.

Ignoring the anomalous result, draw two lines of best fit, making sure that the two lines cross.

Total volume of acid added in cm³

Give the trend shown on the graph for the first 50 cm³ of acid added.

Suggest a mistake the student could have made to cause the anomalous result.

This is the equation for the reaction.

When 50 cm³ of dilute sulfuric acid have been added, only barium sulfate and water are present in the mixture.

Explain why this mixture does not conduct electricity. Refer to the type of bonding in barium sulfate and in water in your answer.

Name a technique the student could use to separate barium sulfate from the mixture after 100 cm³ of dilute sulfuric acid has been added.

A teacher uses this apparatus to reduce tungsten oxide.

This is the teacher’s method.

• record the mass of a weighing boat

• add tungsten oxide and record the mass again

• heat the weighing boat and tungsten oxide strongly for two minutes and then allow to cool

• record the mass of the weighing boat and its contents

Complete the equation by adding the state symbols.

Give an addition to the method to check that the tungsten oxide has been completely reduced.

The table shows the teacher’s results.

Use the teacher’s results to show that the empirical formula of tungsten oxide is WO₃

[for tungsten, A_r = 184 for oxygen, A_r = 16]

The teacher wears eye protection and a lab coat during the experiment.

Give one other safety precaution the teacher should take.

In industry, tungsten oxide is reduced on a large scale using hydrogen.

The percentage yield of tungsten is 73.5%

This is the equation for the reaction.

Calculate the mass, in tonnes, of tungsten that is produced when 2784 tonnes of tungsten oxide are reacted with an excess of hydrogen.

[1 tonne = 110⁶g]

[for tungsten, A_r = 184 for oxygen, A_r = 16]

mass of tungsten =_........ tonnes