2.3 Properties of materials

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.

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

[1]

[1]

Scientists find out some more information about compound X.

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

Use all the information above to justify your answer.

The diagrams show three different structures of carbon.

[1]

[2]

[2]

[1]

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.

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

Explain why graphene is suitable for making touchscreens.

Use the information from the table.

[2]

Look at the data about some hydrocarbons.

Butane contains 4 carbon atoms.

Use the table to suggest the molecular formula of butane.

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

[2]

Answer: …………………………………. °C

Propane burns in oxygen, O₂.

Carbon dioxide and water are made.

Write a balanced symbol equation for this reaction.

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.

Nanoparticles are used as catalysts.

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

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.

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

[2]

[1]

[2]

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.

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

Is she correct?

Explain your answer using evidence from the table.

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

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

[1]

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.

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

Calculate the surface area to volume ratio for this nanoparticle.

Use the equation: ratio = surface area ÷ volume

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

A student is measuring the boiling point of some liquids.

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.

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

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

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

Write a balanced symbol equation for this reaction.

Look at the diagrams of sodium chloride and water.

Sodium chloride has a melting point of 801 °C.

Use the diagram of sodium chloride to explain why.

Water has a low melting point and boiling point.

Explain why.

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.

Look at the data about some substances.

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

Explain how you can tell.

Look at the data about some substances

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

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