topic 4 (majority - just whats needed for mocks)

Question 1

oxidation

Answer 1

gain of oxygen, loss of electrons

Question 2

reduction

Answer 2

loss of oxygen, gain of electrons

Question 3

combustion

Answer 3

involve oxidation

- they are always exothermic

Question 4

reactivity series

Answer 4

list of metals in order of reactivity,

the least reactive are most resistant to oxidation

most reactive easily lose their electrons to form cations

Question 5

reactivity of metals based on how they react with acid

Answer 5

the more reactive the metal the faster the reaction with the acid will go

very reactive metals will fizz vigorously, less reactive will bubble a bit

you can show hydrogen is forming using a burning splint test. the louder the squeaky pop the more hydrogen = more reactive

Question 6

what is an ore

Answer 6

a rock which contains metals often chemically combined with other substances

a rock which contains enough metal to make it economically worthwhile - found in earth’s crust

Question 7

displacement reactions

Answer 7

redox reactions

• more reactive metal is oxidised and less reactive metal is reduced
• more reactive metals displace less reactive ones
  e. g cooper sulfate + iron - iron sulfate + copper

Question 8

explain how some metals can be extracted

Answer 8

a metal can be extracted from its ore chemically by reduction using carbon. When the ore is reduced, oxygen is removed from it. The position of the metal in the reactivity series determines whether it can be extracted by reduction with carbon

Question 9

reduction with carbon and reactivity series

Answer 9

metals higher than carbon in the reactivity series have to extracted using electrolysis (expensive)

metals below carbon in the reactivity series can be extracted by reduction using carbon. (iron oxide is reduced in a blast furnace to make iron)

this is because carbon can only take the oxygen away from metals which are less reactive than carbon itself is

Question 10

electrolysis

Answer 10

• BREAKING DOWN OF A SUBSTANCE USING ELECTRCITY
• once the metal ore is melted an electric current is passed through it. Metal is discharged at cathode, non-metal at the anode
• expensive
• ## large amounts of electricity

Question 11

biological methods to extract metal

Answer 11

bioleaching

phytoextraction

Question 12

bioleaching

Answer 12

uses bacteria to separate metals from their ores. The bacteria get energy from the bonds between the atoms in the ore, separating out the metal. The leachate contains metal ions which can be extracted by electrolysis or displacement electrolysis with a more reactive metal

Question 13

phytoextraction

Answer 13

involves growing plants in the soil that contains metal compounds. The plants can’t be used or get ride of the metal gradually build up in the leaves. The plants can be harvested, dried and burned in a furnace. The ash contains metal compounds from which the metal can be extracted by electrolysis or displacement reactions

Question 14

forward reaction

Answer 14

exothermic A reaction that transfers energy from reactants to the environment. Increase temperature
The position of equilibrium will shift in the endothermic direction. This means that the amount of products generated by the endothermic reaction will increase.

Question 15

backwards reaction

Answer 15

endothermic A reaction that transfers energy from the environment to reactants Increase temperature
The position of equilibrium will shift in the endothermic direction. This means that the amount of products generated by the endothermic reaction will increase.