Properties of materials (OCR Gateway GCSE Chemistry)

Exam Questions

2 hours39 questions
1a4 marks

The diagrams show the structures of diamond and graphite.

q21-paper-1-june-2018-ocr-gcse-chem

One property of diamond is that it is very hard. One property of graphite is that it is slippery.

Write about the other properties of diamond and graphite.

Diamond ...........................................................

Graphite ............................................................

1b1 mark

Describe the type of bonding between the carbon atoms in diamond.

1c2 marks

Graphite is slippery.

Use the structure of graphite to explain why.

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1a2 marks

Look at the diagram. It shows the displayed formula of succinic acid.

q17-paper-1-june-2018-ocr-gcse-chem

Complete the table to show the number of atoms of each element in this displayed formula.

Element Number of atoms
C ..............................
H ..............................
O ..............................

1b1 mark

What is the empirical formula of succinic acid?

1c2 marks

Succinic acid has a melting point of 184°C and a boiling point of 235°C.

What is the state of succinic acid at 25°C?

Explain your answer.

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2a3 marks

A new solid, compound X, has been discovered. Scientists investigated the effect of heat on compound X.

Look at the graph. It shows how the state of compound X changes as it is heated.

q17-paper-1-june-2019-ocr-gcse-chem

i)
What is the melting point of compound X?

Melting point = ................................................. °C[1]

ii)
A scientist describes compound X as a pure substance.
Explain what scientists mean when they describe compounds as pure.

[1]

iii)
Explain how the scientists tell from the graph that compound X is a pure substance.

[1]

2b6 marks

Scientists find out some more information about compound X.

q17b-paper-1-june-2019-ocr-gcse-chem

Describe and explain the type of bonding found in compound X.

Use all the information above to justify your answer.

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3a3 marks

The diagrams show three different structures of carbon.

q20-paper-1-june-2019-ocr-gcse-chem

i)
What is the name of structure Y?

[1]

ii)
Diamond can be described as having a giant lattice structure.

Why is diamond described as a giant lattice structure?

[2]

3b3 marks
i)
Diamond is the hardest naturally occurring substance on Earth.

Explain why diamond is hard.

[2]

ii)
Graphite is used in pencils. Graphite is a soft material.

Explain why graphite is soft.

[1]

3c2 marks

Graphene is another substance made of carbon atoms. Graphene is a single layer of graphite.

It is just one atom thick. Graphene can be used to make touchscreens for electronic devices.

q20c-paper-1-june-2019-ocr-gcse-chem

Look at the table. It shows some properties of graphite and graphene.

Substance Cost

Electrical

conductivity

Density Strength Colour
Graphite low high low low black
Graphene high high low high transparent

Explain why graphene is suitable for making touchscreens.

Use the information from the table.

3d4 marks
i)
Carbon reacts with hydrogen to make methane, CH4.

Complete the dot and cross diagram to show the bonding in methane.

q20d-paper-1-june-2019-ocr-gcse-chem

[2]

ii)
Methane has a low melting point.

Explain why methane has a low melting point.

Use ideas about structure and bonding in your answer.
[2]

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4a1 mark

Look at the data about some hydrocarbons.

Hydrocarbon Number of carbon atoms in molecule Molecular formula Boiling point (°C)
ethane 2 C2H6 –88
propane 3 C3H8 –42
pentane 5 C5H12 36
hexane 6 C6H14 69

Butane contains 4 carbon atoms.

Use the table to suggest the molecular formula of butane.

4b5 marks

The boiling points of ethane and propane have been plotted on the graph.

i)

Plot the boiling points for pentane and hexane on the graph.

Draw the line of best fit.

q21b-paper-1-specimen-2016-ocr-gcse-chemistry

[2]

ii)
Use your graph to estimate the boiling point of butane.
[1]

Answer: …………………………………. °C

iii)
Describe the relationship between the number of carbon atoms in a molecule and its boiling point.

Use ideas about forces between molecules to explain your answer.
[2]
4c2 marks

Propane burns in oxygen, O2.

Carbon dioxide and water are made.

Write a balanced symbol equation for this reaction.

4d
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3 marks

Propane gives out 50 000 J/g when it reacts with oxygen.

  • A propane burner is used to boil water to make a cup of tea.

  • 63 000 J of energy are needed to boil the water.

  • There is only 3 g of propane in the burner.

Do a calculation to find out if there is enough propane in the burner to boil the water.

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5a2 marks

Nanoparticles are used as catalysts.

Describe a property of nanoparticles that make them useful as catalysts.

5b
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2 marks

A student is synthesising a new titanium dioxide (TiO2) nanoparticle for use as a catalyst.

One TiO2 nanoparticle has a mass of 5.0 × 10–3 mg.

Calculate how many TiO2 nanoparticles are in 80.0 mg of TiO2.

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6a5 marks

Lithium is a metal found in Group 1 of the Periodic Table.

i)
Describe the structure and bonding in a metal.

You may include a diagram in your answer.

[2]

ii)
Lithium is malleable even though metallic bonds are strong.

Explain why metals are malleable.

[1]

iii)
Lithium can conduct electricity in the solid and liquid state.

Explain why metals can conduct electricity.

[2]

6b2 marks

An alloy is a mixture of a metal with one or more other elements.

When lithium is mixed with aluminium it makes an alloy that can be used in aircraft.

Adding different amounts of lithium to the aluminium changes the properties of the alloy.

Alloy Percentage
of lithium
(%)
Density
(g/cm3)
Melting
point (°C)
Strength
(MPa)
A 2.00 2.58 670 550
B 2.20 2.56 580 555
C 2.45 2.55 655 565

A scientist thinks that alloy C is best for making an aircraft.

Is she correct?

Explain your answer using evidence from the table.

6c
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2 marks

The scientist uses the particle model to show the elements present in alloy B.

q22c-paper-1-june-2019-ocr-gcse-chem

i)
Calculate the percentage of lithium atoms in the diagram of alloy B.

Percentage of lithium atoms = ..................................................... %

[1]

ii)
Use your answer to part (c)(i) to explain if the diagram accurately shows the structure of alloy B.
[1]

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7a1 mark

A new sun cream has been developed using zinc oxide nanoparticles.

The small particles provide better protection from the sun and they do not leave white marks on the skin.

Explain one possible risk of using nanoparticles in sun cream.

7b4 marks

A cube-shaped nanoparticle has sides of length 50nm.

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Calculate the surface area to volume ratio for this nanoparticle.

Use the equation: ratio = surface area ÷ volume

Surface area to volume ratio = ...................................................

7c
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4 marks
i)
Scientists compare the size of nanoparticles to the sizes of other small objects.

Look at the table.

Object Diameter (nm)
Gold atom 0.14
Water molecule 0.27
DNA strand 2.5
Zinc oxide nanoparticle 32
Red blood cell 7000
Human hair 100000

The diameter of a DNA strand is 2.5nm.

Explain why DNA is a nanoparticle but a water molecule is not a nanoparticle.
[2]
ii)
Calculate how many zinc oxide nanoparticles would fit across a human hair.

Give your answer to 2 significant figures.

Number of nanoparticles = ............................................. [2]

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8a2 marks

A student is measuring the boiling point of some liquids.

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She measures the boiling point of water, petrol and ethanol.

The student’s method is not safe.

Explain why it is not safe and explain how she could improve her method to make it safer.

8b2 marks

The student looks up some data on melting points and boiling points.

Substance Formula Melting point (°C) Boiling point (°C) State at 25 °C
Propane C3H8 –188 –42 .........................
Hexane C6H14 –95 69 .........................
Icosane C20H42 37 343 Solid

Complete the table to show the states of propane and hexane at 25 °C.

8c2 marks

Propane burns in oxygen, O2. Carbon dioxide and water are made.

Write a balanced symbol equation for this reaction.

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9a2 marks

Look at the diagrams of sodium chloride and water.

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Sodium chloride has a melting point of 801 °C.

Use the diagram of sodium chloride to explain why.

9b2 marks

Water has a low melting point and boiling point.

Explain why.

9c3 marks

Magnesium oxide has a similar structure to sodium chloride.

Draw ‘dot and cross’ diagrams to show the ionic bonding in magnesium oxide.

  • Include the charges on the ions.
  • The electronic structure of magnesium is 2.8.2.
  • The electronic structure of oxygen is 2.6.

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106 marks

Look at the data about some substances.

Substance Melting point
(°C)
Boiling point
(°C)
Does it conduct
electricity?
Density (g / cm3)
A 0 100 No 1.0
B 1085 2562 Good conductor 9.0
C 801 1413 Solid does not conduct but conducts when melted or when dissolved in water 2.2

What is the type of bonding present in each of substances A, B and C?

Explain how you can tell.

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116 marks

Look at the data about some substances

Substance  Melting point
(°C)
Boiling point
(°C)
Does it conduct
electricity?
Density
(g / cm3)
A 0 100 no 1.0
B >3000 >4000 no 3.5
C 801 1413 Solid does not conduct
but conducts when melted or when dissolved in water
2.2


Explain the type of bonding present in each substance A, B and C.

Relate the type of bonding to the properties of each substance.

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