Atoms, elements & compounds

The table gives some information about five gases.

Use gases from the table to answer these questions.

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

Name the gas needed for combustion.

Name the gas that is most abundant in air.

Name the gas that can bleach damp litmus paper.

Explain why hydrogen chloride is classified as a compound.

Why does chlorine have the highest boiling point of the gases in the table?

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.

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 gases.

The table gives information about five gases.

Use information from the table to answer these questions. Each gas may be used once, more than once or not at all.

Give the name of the gas that is about 79 % of the atmosphere by volume.

Give the name of the gas that is a compound.

Give the name of the least reactive gas.

Give the name of the gas that is not normally found in the atmosphere.

Give the name of the gas that affects global warming.

Calculate the M_r for carbon dioxide.

Give a reason why it is not possible to give information for air in the table.

When copper(II) carbonate is heated, the products are copper(II) oxide and carbon dioxide.

Give the name for this type of reaction.

Give the colour change that occurs during this reaction.

Give a chemical equation for this reaction.

This question is about mixtures and compounds.

The box gives some techniques used to separate mixtures.

The table lists some substances and mixtures.

Complete the table using words from the box to show the best technique to obtain the named substance from each mixture.

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

State how the box represents a mixture.

Food colourings are mixtures of food dyes.

A student uses paper chromatography to separate the food dyes contained in food colouring D.

The student places spots of three food dyes A, B and C and food colouring D on chromatography paper.

The diagram shows the appearance of the paper after the experiment.

Describe the composition of food colouring D.

A compound has the formula Ca(HCO₃)₂

Determine the number of different elements in Ca(HCO₃)₂

Determine the number of atoms in the formula of Ca(HCO₃)₂

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]

This question is about elements, mixtures and compounds.

Which of these is the formula of a molecule of an element?

Which method can be used to separate an insoluble solid from a liquid?

Give the name of a method used to separate a mixture of liquids with different boiling points.

A student adds a crystal of substance X to some water in a beaker and leaves the beaker for one day.

The diagram shows the beaker immediately after adding the crystal, and after

Which equation gives the correct state symbols for a process that occurs in the beaker?

Which other process occurs in the beaker?

After one day the student does two tests on the liquid in the beaker.

The table shows the student’s results.

Identify substance X.

In this question the answer to each part is a number.

Give the pH value of a neutral solution.

Give a pH value of a weakly acidic solution.

Give the number of the Group in the Periodic Table that contains the elements that do not readily react.

Give the number of different elements present in glucose, C₆H₁₂O₆

The table shows properties of four substances, A, B, C and D.

Use information from the table to identify these substances.

Which substance could be a metal?

Which substance could be diamond?

Which substance is a gas at 600 °C?

One of the substances in the table is a compound with the formula C₁₀H₁₆N₂O₃S

Give the number of different elements in C₁₀H₁₆N₂O₃S

Determine the number of atoms in a molecule of C₁₀H₁₆N₂O₃S

A potassium permanganate crystal is placed in a beaker of water.

After several days a coloured solution forms.

Give the names of the two processes that cause the coloured solution to form.

The formula of potassium permanganate is KMnO₄

How many different types of atom are in KMnO₄?

Calculate the relative formula mass (M_r) of KMnO₄

Potassium permanganate can be used as an oxidising agent.

State what is meant by the term oxidising agent.

This question is about mixtures and compounds.

The box gives some methods used to separate mixtures.

Choose methods from the box to answer the following questions.

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

Identify a method to separate a single food dye from a mixture of food dyes.

Identify a method to separate gasoline from crude oil.

Identify a method to separate water from copper(II) sulfate solution.

The diagram represents a molecule.

Explain why this molecule is a compound.

The molecular formula of another compound is C₃H₅N₃O₉

State the number of different elements in C₃H₅N₃O₉

Determine the number of atoms in a molecule of C₃H₅N₃O₉

Two substances are needed to cause iron to rust.

Name these two substances.

The box gives the names of some substances.

Use words from the box to answer these questions.

Give the name of a non-metallic element.

Give the name of a compound.

Give the name of the metal that is lowest in the reactivity series.

The box lists some substances.

Choose substances from the box to answer these questions.

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

Name a metallic element.

Name a compound.

Name a mixture.

Name an element that is a gas at room temperature.

Name an element that forms a basic oxide.

Name two elements that are in the same group of the Periodic Table.

This question is about gases.

The box gives the names of some gases.

Use gases from the box to answer these questions.

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

Name the most abundant gas in the Earth’s atmosphere.

Name the gas that is a compound.

Name the least reactive of the gases.

Name the gas formed by the complete combustion of hydrocarbons.

Describe the test for hydrogen gas.

The diagram shows the displayed formula of the organic compound methanol, CH₃OH

Determine the number of atoms in one molecule of methanol.

State why methanol is not a hydrocarbon.

The atoms in methanol are held together by covalent bonds.

State what is meant by the term covalent bond.

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

Show only the outer electrons of each atom.

Another organic compound has the percentage composition by mass

C = 38.7% H = 9.7% O = 51.6%

Calculate the empirical formula of this compound.

The relative molecular mass (M_r) of the compound is 62

Determine the molecular formula of the compound.

This question is about elements, compounds and mixtures.

Name the element that burns with a lilac flame.

Name the technique used to separate the mixture of colours in black ink.

The box gives the names of some substances.

Choose substances from the box to answer these questions.

Identify the compound.

Identify the mixture.

Identify the non‑metal element that is a solid at room temperature.

Substances can be classified as elements, mixtures or compounds.

Each box represents an element, a mixture or a compound.

Box 1
Box 2
Box 3
Box 4
Box 5

Which box represents a mixture?

Which two boxes represent elements?

Explain why Box 5 represents a compound.

The Periodic Table contains all the known elements.

How are the elements arranged in the Periodic Table?

Elements in the same group have the same number of

This question is about gases in the atmosphere.

The box gives the names of some gases in the atmosphere.

Use gases from the box to answer the questions.

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

Identify the two noble gases.

Identify the gas that is a compound.

Identify the most abundant gas in the atmosphere.

Identify the greenhouse gas.

Describe the test for oxygen.