Obtaining and Using Metals - Paper 1

Question 1

Recite the reactivity series of metals.

Answer 1

potassium, sodium, calcium, magnesium, aluminium, (carbon), zinc, iron, (hydrogen), copper, silver, gold

Question 2

In what form are metals found?

Answer 2

Most metals are extracted from ores found in the Earth’s crust.
Unreactive metals are found in the Earth’s crust as the uncombined elements.

Question 3

Define oxidation

in terms of oxygen

Answer 3

Oxidation is the gain of oxygen.

Question 4

Define reduction

in terms of oxygen

Answer 4

Reduction is the loss of oxygen.

Question 5

Explain which method of extracting metal from its ore is used for which metals.

Answer 5

If a metal is less reactive than carbon (e.g. iron), it can be extracted from its compounds by heating with carbon.
Otherwise (e.g. aluminium), it can be extracted by electrolysis.

Question 6

Explain the process of phytoextraction.

Answer 6

• Plants are grown on a low-grade ore that contains lower amounts of metal.
• The plants absorb metal ions through their roots and concentrate these ions in their cells.
• The plants are harvested and burnt
  the ash left behind contains a higher concentration of the metal than the original ore.
• The ash is processed to obtain the metal.

Question 7

Evaluate phytoextraction as an alternative method of metal extraction.

Answer 7

• Phytoextraction is slow.
• It reduces the need to obtain new ore by mining.
• It conserves limited supplies of more valuable ores with higher metal content.

Question 8

Explain the process of bioleaching.

Answer 8

Certain bacteria can break down low-grade ores to produce an acidic solution containing metal ions, called leachate.

Question 9

Evaluate bioleaching as an alternative method of metal extraction.

Answer 9

Bioleaching does not need high temperatures, but it produces toxic substances, including sulfuric acid, which damage the environment.
Scrap iron can be used to cheaply displace the copper from the leachate.

Question 10

Give some advantages of recycling metals compared to producing metals from metal ores.

Answer 10

• Less energy is needed to produce a metal.
• Fewer quarries and mines - less noise and less heavy traffic.
• Reserves of metal ores will last longer.

Question 11

Give some disadvantages of the recycling process.

Answer 11

• The collection and transport of used items needs organisation, workers, vehicles and fuel.
• It can be difficult to sort different materials from one another.

Question 12

List the 4 key features of a Life Cycle Assessment (LCA).

Answer 12

• Obtaining the raw materials needed.
• Manufacturing the product.
• Using the product.
• Disposing of the product at the end of its useful life.