Extracting metals

Question 1

what is an ore

Answer 1

a rock that contains metals or their compounds where it will contain enough metal for it to make extraction economical

Question 2

what is a low-grade ore

Answer 2

rocks that don’t have enough metal to make extraction worthwhile

Question 3

how do metals corrode

Answer 3

when they react with substances around them, such as air and water

Question 4

why are some metals found in their native state in the earth’s crust

Answer 4

because they are not reactive and do not combine with other elements

Question 5

what are the 2 ways to chemically extract metals

Answer 5

• electrolysis of a molten compound
• reduction of its oxide using carbon

Question 6

what 5 metals can be extracted using the electrolysis method

Answer 6

potassium
sodium
calcium
magnesium
aluminium

Question 7

what elements can be extracted using the reduction method and why

Answer 7

metals less reactive than carbon, zinc iron copper

Question 8

how are metals extracted using the reduction method

Answer 8

metal oxide and carbon is reacted inside a blast furnace to produce a metal and carbon monoxide or carbon dioxide

Question 9

how are metals extracted using the electrolysis reaction

Answer 9

the metal oxide is dissolved in a molten cryolite, which reduces the temperature needed for electrolysis. as the current passes through aluminium ions gain electrons and are reduced to aluminium atoms at the cathode. at the anode, oxide ions lose electrons and form oxygen gas

Question 10

what method is used to counteract the running out of high-grade iron ores

Answer 10

using scrap iron

Question 11

what is the word equation where scrap iron is used to extract copper from copper salts

Answer 11

iron + copper sulfate –> iron sulfate + copper

Question 12

what is the benefit of using low-grade ore

Answer 12

more common as most high-grade ores have already been used

Question 13

what are 3 cons of low-grade ores

Answer 13

• less profitable
• use more energy
• produce more waste when used

Question 14

what are 2 ways of using biological metal extractions

Answer 14

phytoextraction
bioleaching

Question 15

what happens in phytoextraction

Answer 15

the roots of a plant absorb metal compounds, the plant concentrates the metal compounds in its shoots and leaves. the plant is then burned and ash will contain the metal compound

Question 16

what happens in bioleaching

Answer 16

using bacteria to extract metal by oxidizing compounds and releasing metal ions

Question 17

what is the leachate

Answer 17

the solution that bacteria produce in bioleaching

Question 18

what are 3 cons of extracting materials

Answer 18

uses up limited recources
uses a lot of energy
damages the environment

Question 19

what are 5 pros of recycling metals

Answer 19

metal ores will last longer
less energy is needed
fewer quarries and mines are needed
less noise and dust are produced
less land is needed

Question 20

what are 3 drawbacks of metal recycling

Answer 20

used metal items must be collected and transported to the recycling centre
different metals must be sorted
will save different amounts of energy depending on the metal

Question 21

what is LCA

Answer 21

a life cycle assessment of a product is a “cradle to grave” analysis of its impact on the environment

Question 22

what are the 4 stages of an LCA

Answer 22

obtaining raw material
manufacturing the product
using the product
disposing of the product

Question 23

give 5 pieces of data that an LCA will need

Answer 23

the use of energy
the release of waste materials
transport and storage
whether the raw materials are renewable or non-renewable
whether the product can be recycled or reused
ho the product is disposed of