C10B.3 Rusting

What is the chemical name for rust?

• Iron oxide

• Hydrated iron(III) oxide

• Iron hydroxide

What two substances are needed for iron to rust?

• Oxygen and carbon dioxide

• Water and sodium chloride

• Water and oxygen

Which condition does not lead to rusting of iron?

• Air without water

• Moist air

• Saltwater

Which gas is involved in the oxidation process during rusting?

• Nitrogen

• Oxygen

• Carbon dioxide

What is the role of calcium chloride in rust experiments?

• To catalyse the rusting process

• To remove oxygen from the air

• To absorb water from the air

What is meant by ‘galvanising’?

• Coating iron with a layer of zinc

• Covering iron with plastic

• Painting iron with oil

Why does zinc protect iron even if scratched?

• Zinc is less reactive than iron

• Zinc forms a waterproof layer

• Zinc is more reactive and undergoes sacrificial protection

What is sacrificial protection?

• Removing oxygen from iron’s environment

• Coating iron with aluminium

• Using a more reactive metal to prevent iron from rusting

Why is aluminium used to protect metals?

• It forms a brittle outer coating

• It forms a protective oxide layer

• It absorbs moisture

Which of these is an example of sacrificial protection in real life?

• Painting a car

• Attaching magnesium to iron pipes

• Wrapping iron in plastic