redox rusting wnd iron

Question 1

chemical name for rust

Answer 1

hydrated iron (III) oxide

Question 2

observations for the reaction of copper oxide and hydrogen

Answer 2

-black copper turns red
-condensation seen on boiling tube

Question 3

what’s being oxidised in the reaction between copper oxide and hydrogen

Answer 3

H2 as hydrogen as gained oxygen

Question 4

what being reduced in the reaction between copper oxide and hydrogen

Answer 4

CuO as copper oxide loses oxygen

Question 5

what’s the oxidising agent in the reaction between copper oxide and hydrogen

Answer 5

CuO as it gives oxygen to hydrogen

Question 6

what’s the reducing agent in the reaction of copper oxide and hydrogen

Answer 6

H2 as it takes oxygen from copper oxide

Question 7

why do u keep heating after gas is switched off

Answer 7

to ensure copper stays reduced and isn’t re oxidised

Question 8

safety precaution of reaction between copper oxide and hydrogen

Answer 8

burn off excess H2

Question 9

chemical formula for rust

Answer 9

Fe2O3.xH2O

Question 10

conditions needed for rust

Answer 10

water and oxygen

Question 11

purpose of anhydrous calcium carbonate

Answer 11

absorbs water

Question 12

purpose of boiled water

Answer 12

removes air from water

Question 13

purpose of oil layer

Answer 13

stops oxygen from getting in

Question 14

appearance of rust

Answer 14

red-brown flaky solid

Question 15

why is rust a problem

Answer 15

-weakens metal
-looks unattractive
-costs money to repair

Question 16

preventing rust

Answer 16

-painting
-oiling/greasing
-plastic coating
-plating
-galvanising(coating with zinc)

Question 17

sacrificial protection

Answer 17

mg/zn is more reactive that iron so mg/zn reacts with oxygen/water first, galvanising is also sacrificial protection

Question 18

raw materials in the blast furnace

Answer 18

haematite- iron ore
coke- carbon
limestone- calcium carbonate
hot air in at the bottom

Question 19

step 1 of blast furnace

Answer 19

coke burns in air to form carbon dioxide
C+O2-> CO2
carbon is being oxidised

Question 20

step 2 of blast furnace method

Answer 20

carbon dioxide reacts with more coke to create carbon monoxide
CO2+C-> 2CO

Question 21

step 3 of blast furnace

Answer 21

-iron oxide is reduced by carbon monoxide to iron
-Fe2O3+3CO->2Fe+3CO2
-iron oxide is being reduced carbon monoxide is being oxidised so it’s a redox reaction

Question 22

step 4 of blast furnace

Answer 22

limestone thermally decomposes to form calcium oxide and carbon dioxide
CaCO3-> CaO+ CO2

Question 23

step 5 of blast furnace

Answer 23

-calcium oxide (basic) reacts with (neutralises) silicon dioxide (acidic impurity) to form molten slag
-lies as crust on top of Fe -used for roads and selling reduces process cost
-CaO+ SiO2-> CaSiO3

Question 24

how is iron removed from the blast furnace

Answer 24

iron is removed by the tap at the bottom of the furnace as it’s a molten liquid

Question 25

reducing iron furnaces process cost

Answer 25

recycle iron- doesn’t pollute and cheaper
hot gases-heat trapped and used to heat blasts of hot air into furnace

Question 26

environmental problems of blast furnace

Answer 26

-CO2 produced causing global warming
-CO produced which is a toxic gas
-Noise and dust pollution

Question 27

why is iron/steel so widely used for construction?

Answer 27

it’s strong