IGCSE Coordinated Chemistry Workout 5

When water is heated to 100°C, it changes to steam. The steam has a larger volume than the water.

Which change on heating explains this increase in volume?

• The bonds between hydrogen and oxygen break.

• The molecules become lighter.

• The spacing between the molecules increases.

• The water molecules expand.

A silver coin contains the same number of atoms as a gold coin. Is the mass, and number of electrons, the same for the two coins?

• A

• B

• C

• D

A small piece of element X is dropped into a bowl of water. The diagrams show what happens. When the reaction stops, the remaining solution turns Universal Indicator blue.

To which group of the Periodic Table does element X belong?

• 1

• 3

• 5

• 6

The diagram shows some of the useful products manufactured in the chemical industry from substance X. What is substance X?

• limestone

• methane

• petroleum

• salt

It is unusual for a hot drink to be served in a metal cup. Why is this?

• Metals are usually hard.

• Metals are usually strong.

• Metals have high porosity.

• Metals have high thermal conductivity.

Neon and nitrogen are gaseous non-metals. Which of these elements can be oxidised?

• A

• B

• C

• D

The gas from a leaking cylinder is tested by using damp litmus paper. The damp litmus paper is bleached. What is the gas?

• ammonia

• chlorine

• hydrogen

• oxygen

The diagram shows the electrolysis of acidified water. Gas X ignites with a pop when tested with a lighted splint.

What is gas X and at which electrode is it formed?

• hydrogen at the anode

• hydrogen at the cathode

• oxygen at the anode

• oxygen at the cathode

In the extraction of iron, its ore is first treated with sulphuric acid. This leaves a solid waste which contains unreacted acid.

The best way of treating this waste is to neutralise the acid. How could this be done?

• by adding lime

• by adding rock salt

• by adding sand

• by adding water

The diagram shows apparatus used to investigate the reactivity of metals with a dilute acid. The experiment is repeated using an equal volume of the same acid each time, but changing the metal.

With which metal is the time taken to fill the syringe the shortest?

• copper foil

• copper powder

• magnesium powder

• magnesium ribbon