9F

The gas in the air that reacts with metals most easily is:

• argon

• carbon dioxide

• nitrogen

• oxygen

A metal that does not react with the air is:

• calcium

• gold

• iron

• magnesium

Complete the word equation:

iron + oxygen -->

• iron sulphate

• iron oxide

• carbon dioxide

• carbon monoxide

A copper coin is shiny when it is new, but will eventually go black and dull. The two words which best describe this process are:

• oxidation and neutralisation

• corrosion and neutralisation

• corrosion and reduction.

• oxidation and tarnishing

The gas which is given off when metals react with water is:

• carbon dioxide

• hydrogen

• oxygen

• nitrogen

Complete the word equation:

calcium + water -->

• calcium oxide + carbon dioxide

• calcium sulphate + oxygen

• oxygen + hydrogen

• calcium hydroxide + hydrogen

Reactive metals such as sodium, magnesium and calcium:

• have been known since ancient times because they do not join with other elements.

• are easily extracted from their oxides by heating with carbon which makes carbon dioxide.

• are extracted from their compounds using electricity to break the bonds.

• cannot be extracted from their compounds

  because they are too reactive.

When iron corrodes:

• it evaporates into the air.

• it forms a protective layer on its surface.

• it reacts with chemicals in the environment to form compounds.

• it turns green because it forms a coating of

  copper carbonate

Some window frames are made of a metal which does not need to be painted, because it forms a naturally protective layer. A metal which can be used in this way is:

• copper

• PVC

• iron

• aluminium

Complete the word equation:

magnesium + sulphuric acid -->

• magnesium oxide + hydrogen

• magnesium oxide + sulphur dioxide

• magnesium sulphate + hydrogen

• magnesium sulphate + carbon dioxide