SC11b Ores

Question 1

11.4 Recall that: ​
a) most metals are extracted from ores found in the Earth’s crust ​
b) unreactive metals are found in the Earth’s crust as the uncombined elements

Question 2

11.7 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) ​
b) electrolysis (including aluminium)

Question 3

Higher: 11.8 Evaluate biological methods of metal extraction.

Question 4

what type of metals are found in their native state?

Answer 4

very unreactive metals

Question 5

how are more reactive metals found in nature?

Answer 5

as compounds in rocks

Question 6

what is extraction?

Answer 6

process of obtaining a metal from compounds

Question 7

what is an ore?

Answer 7

rock that contains enough of a compound to extract a metal for profit

Question 8

what ore contains iron oxide?

Answer 8

haematite

Question 9

how is iron extracted from its compound?

Answer 9

heating the iron oxide with carbon which displaces the iron which leaves iron and cardon dioxide

Question 10

Iron oxide + Carbon →

2Fe2O3 + 3C →

Answer 10

Iron + Carbon dioxide​

4Fe + 3CO2​

Question 11

Can all metals be extracted by heating them with carbon?​

Answer 11

no

Question 12

what type of metals can be extracted by heating with carbon?

Answer 12

Only metals less reactive than carbon can be extracted using carbon.​
Metals more reactive than carbon need to be extracted by a more powerful method.​

Question 13

how can more powerful metals be extracted?

Answer 13

electrolysis

Question 14

how does extracting metals by electrolysis work?

Answer 14

Electrolysis involves passing electricity through a molten ionic compound to decompose it into its elements.​

Question 15

what ore is aluminium oxide found in?

Answer 15

bauxite

Question 16

equation for the electrolysis of aluminium oxide with letter number equation

Answer 16

Aluminium oxide → Aluminium + Oxygen​

2Al2O3 → 4Al + 3O2​

Question 17

negative of using electrolysis for extracting metals

Answer 17

very expensive as a lot of energy is needed

Question 18

why are we starting to use new biological methods of extraction rather than heating with carbon? 2

Answer 18

~copper ores are running out
~biological methods don’t release harmful gases

Question 19

negative of using the new biological methods?

Answer 19

take longer

Question 20

what are the 2 biological methods of extraction?

Answer 20

~bioleaching
~phytoextraction

Question 21

what is bioleaching?

Answer 21

~uses bacteria grown on a low grade ore

Question 22

how does bio leaching work?

Answer 22

~bacteria is grown on a low grade ore
~the bacteria produces a solution containing copper ions, called a leachate. ​
~Copper is extracted from the leachate by displacement using scrap iron, then purified by electrolysis.​

Question 23

what metals can bio leaching be used on

Answer 23

~nickel
~cobalt
~zinc
~copper

Question 24

what is phytoextraction?

Answer 24

growing plants that absorb metal compounds

Question 25

how does phytoextraction work?

Answer 25

~Plants are grown ~Metals can be extracted from contaminated soils.​ ~The plants are burned to form ash, from which the metal is extracted. ​

Question 26

advantages of bioleaching? 4

Answer 26

~no harmful gases produced ~less damage to the landscape than mining ~conserves supplies of higher grade ores ~does not require high temperatures

Question 27

disadvantages of bio leaching? 2

Answer 27

~toxic substances and sulfuric acid can be produced by the process, and damage the environment ~very slow

Question 28

advantages of phytoextraction? 5

Answer 28

~no harmful gases produced ~less damage to the landscape than mining ~conserves supplies of higher grade ores ~can extract metals from contaminated soils

Question 29

disadvantages of phytoextraction? 3

Answer 29

~more expensive than mining some ores ~plants cant grow in some weather conditions ~very slow

Question 30

Sodium is more reactive than aluminium. Describe a method to extract sodium from sodium chloride. Give a reason for your answer. (3 marks)

Answer 30

~Electrolysis. ​ ~Sodium is more reactive than carbon ​ ~so carbon cannot be used to extract it.