Chemical changes - Oxidation, reduction, redox

Question 1

what is an oxidation reaction

Answer 1

a reaction that involves gaining oxygen, can also involve losing electrons

Question 2

What is a reduction reaction

Answer 2

a reaction where oxygen is lost,can also be when electrons are gained

Question 3

what does OILRIG stand for

Answer 3

oxidation is loss ( of electrons ) reduction is gain

Question 4

example of an oxidation reaction

Answer 4

2Mg + O2 – 2MgO

magnesium is oxidised to make magnesium oxide

Question 5

example of reduction reaction

Answer 5

2CuO + C – 2Cu + CO2

copper oxide is reduced to copper

Question 6

how are metals extracted from their ores

Answer 6

by reduction using carbon

- in the reaction, the ore is reduced as oxygen is removed from it and carbon gains oxygen so is oxidised

Question 7

how are metals with higher reactivity than carbon extracted

Answer 7

using electrolysis

Question 8

what is a redox reaction

Answer 8

a reaction where oxidation and reduction happen at the same time, also when electrons are transferred

Question 9

example of redox reactions

Answer 9

displacement reactions, where a more reactive metal displaces a less reactive one in a compound

• for example iron + copper sulfate – iron sulfate + copper
• the iron loses 2 electrons, becomes a 2+ ion and is oxidised
• copper gains 2 electrons to become a copper atom, it’s reduced

Question 10

in displacement reactions, what gets oxidised and what gets reduced

Answer 10

• less reactive metal is reduced
• more reactive metal is oxidised

Question 11

what is an ionic equation

Answer 11

an equation which only shows the particles that react and the products they form

Question 12

what are spectator ions

Answer 12

ions that don’t change during the reaction and can be crossed out in an ionic equation

Question 13

why is carbon used to extract metals

Answer 13

because it’s cheap and abundant