corrosion

Question 1

definition

Answer 1

gradual destruction of metals because of chemical reactions between metals and the oxygen and water around them

Question 2

rusting reaction

Answer 2

iron + water + oxygen –> hydrated iron (III) oxide

Question 3

preventing corrosion

Answer 3

applying coating eg paint that acts as a barrier
sacrificial method- metal requiring protection will have a more reactive metal attached to it ( water and oxy will react will sacrificial metal rather than one being protected)
galvanising- hybrid of coating and sacrificial method

Question 4

disad of barrier

Answer 4

if coating is damaged, metal will become exposed and start corroding

Question 5

steel

Answer 5

alloys of iron that contain carbon and other metals
high carbon - strong but brittle
low carbon- soft but malleable
stainless steel- strong and resistant to corrosion

Question 6

bronze

Answer 6

alloy of copper and tin
adding tin increases hardness
uses: coins, statues , electrical hardware

Question 7

uses of high/low carbon/ stainless steel

Answer 7

high c- cutting tools and blades
low c - car bodies
stainless steel- cooking utensils and cutlery

Question 8

gold

Answer 8

silver/ copper / zinc often added to produce more resilient substance due to softness of pure gold
24 carats= pure gold

Question 9

brass

Answer 9

alloy of copper and zinc
zinc makes material more malleable
uses - hinges, locks, plumbing, plug sockets

Question 10

aluminium

Answer 10

alloys have low density
uses- manufacturing planes, armour plating for military vehicles