Reactions of Metals

Reactions of Metals

Reactions of Metals

Metal Oxides

Salts and hydrogen

React with oxygen to give React with acids to give

Example of Metal Reactions

Iron

Iron is moderately reactive.

It will react with steam or acids to displace Hydrogen Fe + 2HCl FeCl² + H²

Copper

Is one of the least reactive metals.

Does not react with dilute acid

If the metal is heated in air a black layer of copper oxide is formed.

2Cu + O² 2CuO

Example of Metal Reactions

• Copper statues and roofs become coated with a green layer of copper (II) carbonate.

• Copper carbonate will decompose on heating to release carbon dioxide.

CuCO³ CuO + CO²

Tests for Copper

• Compounds of copper give a blue green flame.

• Solutions of copper salts give a gelatinous precipitate of copper

hydroxide if sodium hydroxide is added.

• If the precipitate is heated it will turn black as it is unstable and it is converted to copper oxide.

• Ammonia solutions will also produce the same precipitate but will re-dissolve on adding excess solution.

Example of Metal Reactions

Zinc

Zinc is a moderately reactive metal.

It will displace hydrogen from steam or dilute acids.

Zn + H²O ZnO H²

Zn + 2HCl ZnCl² + H²

Example of Metal Reactions

Zinc carbonate decomposes on heating to give off carbon dioxide

ZnCO³ ZnO + CO²

Reactivitly of Metals

Reactivity of Metals

• Most elements in the periodic table are metals.

• Reactivity changes in particular groups.

• Reactivity:

• Reactivity is determined by investigating the following for a metal;

– Ease of extraction – Reaction with oxygen – Reaction with water

– Reaction with dilute acids

– Metal displacement in redox reactions – Heat stability

Reactivity Series

Extraction Techniques

• Electrolysis of molten ores

• Reduction of

oxides with carbon

• Occur native in the ground

Metal Displacement Reaction

• Use it to compare the reactivity of two metals.

• A more reactive metal displaces a less reactive metal.

• The metals are in direct competition.

Displacement Reaction

• Zinc displaces copper from solution so zinc is more reactive than copper.

• Zn + CuSO⁴ ZnSO⁴ + Cu

Redox Reactions

• Aluminium, the more reactive metal, removes oxygen from the less reactive iron.

Fe²O³ + 2Al Al²O³ + 2Fe

Activity

• Questions of page 239 and 244

• Exam style questions on page 246