Edexcel IGCSE Chemistry Chemistry Paper 1 June 2024 question paper 4CH1/1CR

This question is about atomic structure.

The table shows the number of protons, neutrons and electrons in five species, V, W, X, Y and Z.

The letters represent the species but are not symbols from the Periodic Table.

Choose letters from the table to answer these questions.

Each letter may be used once, more than once or not at all.

Which species is an atom?

Which species is an ion with a positive charge?

Which species is an ion with a 3− charge?

State what is meant by the term atomic number.

State what is meant by the term mass number.

This question is about methane, CH₄

The diagram shows a Bunsen burner that uses methane.

During combustion, methane reacts with a gas in the air.

Give the name of this gas.

Give the two products of the complete combustion of methane.

During the incomplete combustion of methane, carbon monoxide forms.

Give a reason why carbon monoxide forms during incomplete combustion.

State why carbon monoxide is poisonous.

The equation shows the reaction of methane with bromine.

Give the name of this type of chemical reaction.

This question is about elements, mixtures and compounds.

The box gives some methods used to separate mixtures.

Choose methods from the box to answer these questions.

Identify a method to remove sand from a mixture of sand and seawater.

Identify a method to separate a mixture of liquids with different boiling points.

The diagram shows part of the structure of silicon dioxide.

Explain why silicon dioxide is a compound.

The molecular formula of the compound insulin is C₂₅₇H₃₈₃N₆₅O₇₇S₆

Determine the number of different elements in C₂₅₇H₃₈₃N₆₅O₇₇S₆

Determine the number of atoms in a molecule of C₂₅₇H₃₈₃N₆₅O₇₇S₆

Magnalium is a mixture of magnesium atoms and aluminium atoms.

The diagram shows a sample of magnalium.

Calculate the percentage of magnesium atoms in this sample.

This question is about the alkali metals.

A teacher demonstrates the reaction between sodium and water.

The teacher fills a trough with water and then adds a piece of sodium.

The sodium reacts with the water, forming bubbles of hydrogen gas and a colourless solution.

State two other observations that would be made.

Give a test to show that, at the end of the reaction, the solution contains sodium ions.

Lithium, sodium and potassium react in a similar way when added to water.

State, with reference to the electronic configurations of atoms, why these elements have similar reactions.

The table shows the atomic radius of a lithium atom, a sodium atom and a potassium atom.

Deduce the relationship between the atomic radius and the reactivity of the metals.

Chromatography is used to separate the components in a mixture.

Diagram 1 shows the apparatus used to separate the different dyes in a food colouring.

Diagram 1

Complete the diagram by adding the missing labels.

Give a reason why the baseline is drawn in pencil.

Diagram 2 shows a chromatogram produced from four different food colourings, W, X, Y and Z.

Which two food colourings contain the same dye?

Calculate the R_f value of the dye in food colouring W.

A student uses this apparatus to find the heat energy released by the combustion of liquid fuels.

Explain what is meant by the term fuel.

In one experiment, the student uses liquid ethanol as the fuel.

The thermometer shows the temperature of the water at the start of the experiment.

Complete the table by giving the temperatures to the nearest 0.1 °C.

The metal can contains water of mass 150 g.

Show, by calculation, that the heat energy change (Q) for this reaction is approximately 36 000 J.

[for water, c = 4.2 J/g/°C]

In the experiment, 2.3 g of ethanol (M_r = 46) is burned.

Calculate the molar enthalpy change (Δ H), in kJ/mol, for the combustion of ethanol, C₂H₅OH

Include a sign in your answer.

Give your answer to two significant figures.

In this experiment, the calculated value of Δ H is less than the value given in a data book.

Give a possible reason for the difference in values.

A student uses this apparatus to investigate the rate of reaction between dilute sulfuric acid and an excess of small pieces of zinc.

This is the student’s method.

Step 1 use 50 cm³ of dilute sulfuric acid

Step 2 add approximately 5 g of small zinc pieces to the sulfuric acid

Step 3 quickly connect the gas syringe

Step 4 record the reading on the gas syringe every 30 seconds until the reaction stops

Name a suitable piece of apparatus to measure the volume of sulfuric acid.

Give a reason why the mass of zinc pieces does not need to be measured accurately.

Give a reason why the student quickly connects the gas syringe in step 3.

State how the student would know when the reaction stops.

The graph shows the volume of gas collected in the syringe during the experiment.

A tangent to the curve has been drawn at a time of 80 s.

Use the tangent to calculate the rate of reaction at 80 s.

Show your working on the graph.

Give the unit.

Explain the shape of the graph in these regions.

from 0 s to 60 s

from 60 s to 150 s

from 150 s to 240 s

This question is about crude oil.

Describe how crude oil is separated into fractions by fractional distillation.

Some of the products of fractional distillation are then cracked.

This equation represents a reaction that occurs during cracking.

Explain why cracking is an important process in the oil industry.

Fuels obtained from crude oil may contain impurities.

Explain how an impurity found in fuels can cause an environmental problem.

The table shows the formulae of some positive and negative ions, and the formulae of some compounds containing these ions.

Complete the table by giving the formulae of the missing compounds.

Give the name of the compound with the formula ZnSO₄

Hydrogen chloride and magnesium chloride have different types of bonding and have different structures.

Complete the dot-and-cross diagram to show the outer shell electrons in a molecule of hydrogen chloride.

H C l

The diagram shows the electronic configuration of a magnesium atom and of a chlorine atom.

Draw the electronic configuration of a magnesium ion and of a chloride ion in the boxes.

Show the charge on each ion.

Explain why magnesium chloride has a much higher melting point than hydrogen chloride.

Refer to structure and bonding in your answer.

This is the equation for the decomposition of hydrogen peroxide.

The rate of reaction increases when a catalyst of manganese(IV) oxide is added.

Describe how a catalyst increases the rate of a reaction.

A student adds 50 cm³ of hydrogen peroxide solution to a glass container and then adds 1.0 g of manganese(IV) oxide.

The diagram shows the apparatus the student uses.

Name the glass container the student uses.

The student waits until the hydrogen peroxide solution completely decomposes.

Describe how the student could then show that the manganese(IV) oxide was a catalyst and not a reactant.

Diamond and graphite are both forms of the element carbon.

Diamond and graphite both have covalent bonds and giant covalent structures.

The diagram represents the structure of diamond and the structure of graphite.

Give a reason why diamond is an element.

Describe the forces of attraction in a covalent bond.

Explain why graphite conducts electricity.

Explain why diamond is hard but graphite is soft.

Another form of carbon has molecules with the formula C_x

x represents the number of carbon atoms in each molecule.

Each molecule of C_x has a mass of 1.40 × 10⁻²¹ g.

One mole of C_x contains 6.02 × 10²³ molecules.

Calculate the M_r of C_x and the value of x

[for carbon, A_r = 12]

This question is about the metal tantalum, Ta.

Tantalum metal can be produced by heating tantalum chloride (TaCl₅) and hydrogen gas in a furnace.

The other product of the reaction is hydrogen chloride.

Complete the equation for the reaction.

As tantalum chloride is heated, the mass of solid in the furnace decreases leaving tantalum as the only solid product.

The table shows the mass of solid in the furnace at one-hour intervals.

State how the data in the table shows that the reaction is complete.

Use the data to show that the formula of tantalum chloride is TaCl₅

[for tantalum, A_r = 181 for chlorine, A_r = 35.5]

QUESTION 12 CONTINUES ON NEXT PAGE.

Another method of extracting tantalum is by reacting tantalum(V) oxide with carbon.

This is the equation for the reaction.

Explain why this is a redox reaction.

2000 mol of tantalum(V) oxide is heated with 500 000 g of carbon.

Show by calculation that the carbon is in excess.

[for carbon, A_r = 12]

Calculate the maximum mass, in grams, of tantalum that can be obtained from 2000 mol of tantalum(V) oxide.

[for tantalum, A_r = 181]