Topic 4- extracting metals and equilibria

Deduce the relative reactivity of some metals, by their reactions

with water, acids and salt solutions

Most reactive - react with water

(metal + water = metal hydroxide + hydrogen)

Reactive - react with acid

(metal + acid = salt + hydrogen)

Least reactive - react with oxygen

(metal + oxygen = metal oxide)

4.2 Explain displacement reactions as redox reactions, in terms of gain or loss of electrons

In displacement reactions, both oxidation and reduction takes place.

- Most reactive metal is oxidised. (loses electrons)

- Least reactive metal is reduced. (gain electrons)

what is the reactivity series

how are most metals extracted

from ores found in the Earth's crust

where are unreactive metals found

in the Earth's crust as the uncombined elements

what is oxidation

gain of oxygen

what is reduction

loss of oxygen

what do the extraction of metals involve

the reduction of ores

4.7 Explain why the method used to extract a metal from its ore is related to its position in the reactivity series and the cost of the extraction process, illustrated by

a heating with carbon (including iron)

Ores are reduced using carbon to extract metals.

e.g iron oxide + carbon = iron + carbon dioxide

- Cheaper than electrolysis

(zinc - copper)

4.7 Explain why the method used to extract a metal from its ore is related to its position in the reactivity series and the cost of the extraction process, illustrated by

b electrolysis (including aluminium)

Ores are reduced using electrolysis to extract metals.

e.g aluminium oxide = aluminium + oxygen

- Requires large amounts of energy so very expensive

(aluminium - potas sium)

How to extract metals using biological processes (bacterial and phytoextraction)

Bioleaching/bacterial:

• The bacteria produce a solution containing copper ions called a leachate

• copper extracted from leachate using displacement using scrap iron then purified by electrolysis

Phytoextraction

• involves growing plants that absorbs metal compounds

• plants are burnt to form ash from which the metal is extracted

4.9 Explain how a metal's relative resistance to oxidation is related to its position in the reactivity series

The higher on the reactivity series, the least resistant to oxidation (the gain of electrons)

advantages of recycling

• ores supplies are finite

• prevents waste of metal

• use less energy than for extraction

• lower use of fossil fuels

• less greenhouse gases used

• reduced damage to habitats from the mining process

• does not end up in landfill

Describe that a life-cycle assessment for a product involves

consideration of the effect on the environment of obtaining the

raw materials, manufacturing the product, using the product