Edexcel IGCSE Chemistry Chemistry Paper 1 June 2023 question paper 4CH1/1C

The box gives some methods that are involved in the separation of mixtures.

Use words from the box to identify the method involved in each of these separations.

Give the best method for obtaining gasoline from crude oil.

Give the best method for separating the dyes in black ink.

Give the best method for obtaining pure water from seawater.

A sample of solid hydrated copper(II) sulfate can be obtained from a mixture of copper(II) oxide and copper(II) sulfate.

Complete the passage by using words from the box.

The mixture of copper(II) oxide and copper(II) sulfate can be separated by first

_........ the copper(II) sulfate in distilled water.

The copper(II) oxide is then removed by

Some of the water from the copper(II) sulfate solution is then removed by

A pure sample of hydrated copper(II) sulfate is then obtained by

This question is about the reactions of iron.

Iron rusts when exposed to water and oxygen.

Give the chemical name of the compound that forms when iron rusts.

What type of reaction occurs when iron rusts?

Galvanising is a method used to prevent iron from rusting.

Give the name of the metal used to galvanise iron.

When iron reacts with dilute sulfuric acid, the products are iron(II) sulfate and hydrogen.

Give a chemical equation for the reaction between iron and sulfuric acid.

Give a test for hydrogen.

An excess of iron is added to copper(II) sulfate solution.

Name the type of reaction that occurs.

State the appearance of the solid that forms in the reaction.

Give the reason why no reaction occurs when iron is added to magnesium sulfate solution.

The table gives some information about three substances, X, Y and Z.

Complete the table by giving the missing information.

Explain why substance X has a low melting point.

This question is about unsaturated hydrocarbons.

Ethene (C₂H₄) is a member of the homologous series of alkenes.

Give two characteristics of a homologous series.

Draw a dot-and-cross diagram to show the bonding in a molecule of ethene.

Show outer electrons only.

Propene (C₃H₆) is another member of the homologous series of alkenes.

State why the empirical formula of all alkenes in this homologous series is CH₂

Propene can be polymerised to form poly(propene).

Draw the displayed formula of propene and the repeat unit of poly(propene).

propene
repeat unit of poly(propene)

This is the structural formula of another hydrocarbon compound.

Give the molecular formula and the empirical formula of this compound.

molecular formula

empirical formula

Explain why this compound is an unsaturated hydrocarbon.

Describe a test to show that this hydrocarbon is unsaturated.

This question is about lithium and some of its compounds.

A small piece of lithium is added to a trough containing water.

The lithium floats on the surface of the water and a vigorous reaction occurs.

Give two other observations when lithium reacts with water.

A few drops of methyl orange are added to the solution in the trough.

Explain the final colour of the solution.

An unlabelled bottle containing a white powder is found in a laboratory.

Describe tests to show that the white powder in the bottle is lithium carbonate.

Lithium carbonate has ionic bonding.

State what is meant by the term ionic bonding.

When solutions of lead(II) nitrate and potassium chloride are mixed, a precipitate of lead(II) chloride forms.

Complete the equation for the reaction by adding the state symbols.

Give the formula of each ion in lead(II) nitrate.

lead ion

nitrate ion

Calculate the relative formula mass (M_r) of lead(II) nitrate, Pb(NO₃)₂

A student investigates the height of the precipitate formed when lead(II) nitrate solution is added to potassium chloride solution.

This is the student’s method.

Step 1&$pour=NRKM cm³ of potassium chloride solution into a boiling tube

Step 2&$~dd=OKM cm³ of lead(II) nitrate solution and allow the precipitate to settle

Step 3 measure the height of the precipitate

Repeat steps 2 and 3 until a total of 14.0 cm³ of lead(II) nitrate solution has been added.

The table shows the student’s results.

Plot the results on the grid.

Draw a circle around the anomalous result.

Draw a line of best fit through the first four points and another line of best fit through the last three points. Make sure that the lines cross.

Volume of lead(II) nitrate in cm³

Give two possible mistakes the student could have made to cause the anomalous result.

State why the first line of best fit should pass through the origin.

Use your graph to determine the volume of lead(II) nitrate solution needed to react completely with 15.0 cm³ of potassium chloride solution.

This question is about the three halogens, bromine, chlorine and iodine.

Give the number of protons and the number of neutrons in an atom of iodine–127

number of protons

number of neutrons

A sample of bromine contains two isotopes.

• Br–79 with relative abundance 52.8 %

• Br–81 with relative abundance 47.2 %

Calculate the relative atomic mass (A_r) of this sample of bromine.

Give your answer to three significant figures.

Aluminium reacts with chlorine to form aluminium chloride.

This is the equation for the reaction.

Calculate the minimum mass of chlorine needed to form 26.7 g of aluminium chloride.

[for Cl₂, M_r = 71 for AlCl₃, M_r = 133.5]

A student mixes the following pairs of solutions.

Pair 1 bromine solution and potassium chloride solution

Pair 2 bromine solution and potassium iodide solution

Explain how the student can use the results of these experiments to show the order of reactivity of the three halogens, bromine, chlorine and iodine.

Include observations in your answer.

A student uses this apparatus to find the molar enthalpy change (Δ H) of combustion for the liquid fuel, pentanol.

This is the student’s method.

• find the initial mass of the spirit burner and pentanol

• add 100 cm³ of water to the copper can

• record the initial temperature of the water

• light the wick of the spirit burner to heat the water

• stir the water until the temperature rises by 35.0 °C

• extinguish the flame and immediately find the final mass of the spirit burner and pentanol

State why the student stirs the water.

Suggest why it is important that the student immediately finds the final mass of the spirit burner and pentanol.

The diagram shows the initial temperature of the water.

Complete the table to show the temperature readings.

Give both values to the nearest 0.1 °C.

Show by calculation that the heat energy (Q) supplied by the pentanol is approximately 15 000 J.

[for water, c = 4.2 J / g / °C]

[for 1.0 cm³ of water, mass = 1.0 g]

The table gives the initial and final mass readings.

Use your answer to part (c)(i) and the information in the table to calculate the molar enthalpy change (Δ H) of combustion, in kJ / mol, for pentanol.

[for pentanol, M_r = 88]

Include a sign in your answer.

ΔH for pentanol =_........ kJ / mol

The formula of pentanol is C₅H₁₁OH

Write a chemical equation for the complete combustion of pentanol.

This question is about different hydrated forms of sodium sulfate.

A compound has the formula Na₂SO₄.7H₂O

How many different elements are there in the formula Na₂SO₄.7H₂O?

What is the total number of atoms in the formula Na₂SO₄.7H₂O?

Another hydrated form of sodium sulfate has the formula Na₂SO₄.xH₂O

A student uses this apparatus to find the value of x.

This is the student’s method.

• find the mass of an empty tube

• add solid hydrated sodium sulfate to the tube

• find the mass of the tube and hydrated sodium sulfate

• heat the tube for several minutes

• allow the tube to cool and find the mass of the tube and contents

Describe what the student should do next to make sure that all the water is removed from the hydrated sodium sulfate.

Explain the role of the ice in the beaker.

Describe how the student could prove that the liquid collected is pure water.

The table gives the student’s results.

Use the student’s results to calculate the value of x.

[for Na₂SO₄, M_r = 142 for H₂O, M_r = 18]

Zinc reacts with dilute hydrochloric acid to form zinc chloride and hydrogen gas.

This is the equation for the reaction.

In an experiment, 20 cm³ of hydrochloric acid containing 0.0036 mol are reacted with 1.3 g of zinc granules at a temperature of 30 °C.

Show by calculation that the zinc is in excess.

The volume of hydrogen collected is measured at regular time intervals.

Curve A shows the results of this experiment.

The experiment is repeated using 1.3 g of zinc powder instead of zinc granules.

All other conditions are kept the same.

On the grid, draw the curve you would expect to obtain.

In the original experiment, 20 cm³ of hydrochloric acid containing 0.0036 mol were reacted with 1.3 g of zinc granules at a temperature of 30 °C and curve A was obtained.

The student does two more experiments and obtains curves B and C.

In one of these experiments the student repeats the original method but at a temperature of 20 °C.

Explain in terms of particle collision theory why the curve obtained could be curve B.

In the other experiment the student repeats the original method but uses 20 cm³ of hydrochloric acid containing 0.0018 mol.

Explain why curve C shows the results the student obtained.

Catalysts can be used to speed up reactions.

Describe how a catalyst works.