IGCSE Coordinated Chemistry Workout 36

Which metal cannot be extracted from its ore by heating with carbon?

• copper

• aluminium

• iron

• zinc

Which statement explains how oxides of nitrogen are formed in a car engine?

• Nitrogen in the air reacts with the fuel.

• Oxygen and nitrogen in the air react together.

• Oxygen in the air reacts with nitrogen impurities in the fuel.

• Oxygen in the air reacts with the fuel.

The diagram shows an experiment about the rusting of iron. The apparatus is left for one week. Which row completes gaps 1 and 2?

After one week the water level has risen up the test-tube by ..1.. The remaining gases in the air, including ..2.., do not react with the iron.

• 1 = 20% and 2 = nitrogen

• 1 = 20% and 2 = oxygen

• 1 = 79% and 2 = nitrogen

• 1 = 79% and 2 = oxygen

Why do farmers add fertilisers to soil?

• It adds nitrogen, phosphorous and potassium to the soil.

• It adds nitrogen, phosphorous and calcium to the soil.

• To decrease the pH of the soil.

• To increase the pH of the soil.

Which structure represents a molecule of but-1-ene?

• A

• B

• C

• D

Collagen is a protein.

Boiling collagen with dilute acid produces amino acids.

What is the name of this process?

• condensation

• cracking

• hydrolysis

• polymerisation

Which row shows the electronic structure of a calcium atom and of a fluoride ion?

• A

• B

• C

• D

The electrolysis of concentrated aqueous sodium chloride is an important industrial process. Which words complete gaps 1, 2 and 3?

During this process ..1.. is produced at the cathode and ..2.. is produced at the anode. The solution formed turns litmus ..3.. .

• A

• B

• C

• D

In which word equation is the underlined substance being oxidised?

• carbon dioxide + carbon → carbon monoxide

• carbon monoxide + iron oxide → carbon dioxide + iron

• copper oxide + magnesium → magnesium oxide + copper

• magnesium oxide + hydrochloric acid → magnesium chloride + water

The equation for the reaction between aqueous calcium chloride and aqueous potassium sulfate is shown.

CaCl_2(aq) + K₂SO_4(aq) → CaSO_4(s) + 2KCl_(aq)

Which process is not used to produce the pure salt calcium sulfate?

• crystallisation of the salt from solution

• filtration to collect the salt

• mixing two soluble salts together

• washing the salt with cold water