OCR Gateway GCSE Combined Science June 2018 Paper 3: timed practice

4 marksFoundation

Spec and skills

Some substances are listed below. Copper, carbon dioxide, air, sodium chloride.

.1

Which substance is an element?

[1 mark]

.2

Which substance is a mixture?

[1 mark]

.3

Give the number of different elements in the formula

\mathrm{CaCO_{3}}

.

[1 mark]

.4

A student has a mixture of sand and water. Choose the best method to get the sand.

[1 mark]

6 marksFoundation and Higher

Spec and skills

Diamond and graphite are both forms of carbon.

Compare the structure and bonding of diamond and graphite, and use them to explain the differences in hardness and electrical conductivity.

[6 marks]

6 marksFoundation and Higher

Spec and skills

A student investigates what is produced when aqueous solutions of copper chloride and sodium chloride are electrolysed using inert electrodes.

Plan an investigation to find the products at each electrode for both solutions. Include how you would identify any gases.

[6 marks]

4 marksFoundation and Higher

Spec and skills

Aluminium oxide is an ionic compound. It contains

\mathrm{Al^{3+}}

and

\mathrm{O^{2-}}

ions.

.1

Write the formula of aluminium oxide.

[1 mark]

.2

Describe the structure of aluminium oxide.

[3 marks]

6 marksFoundation and Higher

Spec and skills

A student wants to make pure, dry crystals of copper sulfate from copper oxide (an insoluble black powder) and dilute sulfuric acid.

Plan a method the student could use. In your answer, explain the reason for each step.

[6 marks]