Practice Paper 1 (Edexcel IGCSE Chemistry)

This question is about ammonium chloride.

Give the formula of the ammonium ion.

Describe a test to show that ammonium chloride contains ammonium ions.

The equation shows the thermal decomposition of ammonium chloride.

NH₄Cl(s) $\rightleftharpoons$ NH₃(g) + HCl(g)

State what the $\rightleftharpoons$ symbol indicates about this reaction.

The diagram shows the formation of ammonium chloride in a glass tube.

i) Explain how the mean speed of ammonia molecules compares with the mean speed of hydrogen chloride molecules.

ii) Gas particles travel very quickly.

Give two reasons why it takes several minutes for the ammonium chloride to form.

This question is about the solubility of salts.

The table shows how the solubility of a salt in water varies at six different temperatures.

i) Plot the points on the grid provided

ii) Draw the curve of best fit

A saturated solution of the salt in 100 g of water is cooled from 60°C to 10°C.

Using your graph, find the mass of salt that crystallises out as the solution cools.

Indicate your working clearly on the graph.

When solutions of lead nitrate and potassium sulfate are mixed, one product is solid lead sulfate.

This is the equation for the reaction.

Pb(NO₃)₂ (aq) + K₂SO₄ (aq) → PbSO₄ (s) + 2KNO₃ (aq)

Identify, at the end of the reaction,

the solute: ............................................

the solvent: ..........................................

the solution: ........................................

Which pair of solutions produces an insoluble salt when mixed?

The table shows information about the two isotopes of boron.

The relative atomic mass of this sample of boron is:

Use the Periodic Table to help you answer this question.

i) Name the element with atomic number 14

ii) Name the element with a relative atomic mass of 11

iii) Name the element in Group 2 and Period 3

i) Determine the number of neutrons in a phosphorus atom with mass number 31

ii) State the electronic configuration of an aluminium atom.

iii) State why neon is unreactive.

This question is about alkanes.

The graph shows the boiling points of several unbranched alkanes.

i) Draw a curve of best fit.

ii) Use the graph to find the boiling point of the alkane with 7 carbon atoms in its molecule.

Show on the graph how you obtain your answer.

boiling point = .............................................................. °C

iii) Explain the trend shown by the graph.

The diagram represents two isomers with the formula C₅H₁₂

Explain why these compounds are isomers.

i) An alkane contains 82.8% carbon and 17.2% hydrogen by mass. Show by calculation that the empirical formula of this alkane is C₂H₅

ii) Deduce the molecular formula of this alkane.

The equation for the complete combustion of one mole of an alkane can be represented by

alkane + ZO₂ → XCO₂ + YH₂O

Complete combustion of one mole of the alkane produces 308 g of carbon dioxide and 144 g of water.

X, Y and Z are the numbers used to balance the equation.

Calculate the values of X, Y and Z.

[M_r of CO₂ = 44, M_r of H₂O = 18]

X = ................................

Y = ................................

Z = ................................

Which of the following dot-and-cross diagrams shows the correct arrangement of electrons in lithium sulfide?

The diagram shows the structures of three substances that have giant covalent structures.

Which does not provide the correct explanation of the property of a substance?

Copper is a typical metal.

Explain how the particles in copper are held together and why the metal is malleable.

You may use a diagram in your answer.

Metals are good conductors of electricity.

Electrical conductivity increases across Period 3, from sodium to aluminium.

Explain why.

Copper can react with oxygen to form copper (II) oxide. Explain the charge on the oxide ion.

Write a half equation for the process that copper undergoes when it reacts with oxygen.

This question is about the electrolysis of copper(II) sulfate solution.

The diagram shows the apparatus used for the electrolysis.

A student records the total increase in mass of the negative electrode every minute for 8 minutes.

The table shows the results.

i) Plot the student’s results.

ii) Draw a curve of best fit.

iii) Explain the shape of the graph.

The product at the positive electrode is oxygen gas.

i) The student repeats the electrolysis using different apparatus.

Describe how the student should collect a sample of pure oxygen at the positive electrode.

ii) Give an ionic half-equation for the formation of oxygen.

The wire used to connect the power supply to the electrodes is made of copper metal.

The diagram shows the arrangement of the ions in a metal.

i) Metals that are malleable can also be stretched to form long, thin wires.

Suggest why metals can be stretched to form wires.

ii) Explain why metals conduct electricity.