redox rusting wnd iron Flashcards
chemical name for rust
hydrated iron (III) oxide
observations for the reaction of copper oxide and hydrogen
-black copper turns red
-condensation seen on boiling tube
what’s being oxidised in the reaction between copper oxide and hydrogen
H2 as hydrogen as gained oxygen
what being reduced in the reaction between copper oxide and hydrogen
CuO as copper oxide loses oxygen
what’s the oxidising agent in the reaction between copper oxide and hydrogen
CuO as it gives oxygen to hydrogen
what’s the reducing agent in the reaction of copper oxide and hydrogen
H2 as it takes oxygen from copper oxide
why do u keep heating after gas is switched off
to ensure copper stays reduced and isn’t re oxidised
safety precaution of reaction between copper oxide and hydrogen
burn off excess H2
chemical formula for rust
Fe2O3.xH2O
conditions needed for rust
water and oxygen
purpose of anhydrous calcium carbonate
absorbs water
purpose of boiled water
removes air from water
purpose of oil layer
stops oxygen from getting in
appearance of rust
red-brown flaky solid
why is rust a problem
-weakens metal
-looks unattractive
-costs money to repair
preventing rust
-painting
-oiling/greasing
-plastic coating
-plating
-galvanising(coating with zinc)
sacrificial protection
mg/zn is more reactive that iron so mg/zn reacts with oxygen/water first, galvanising is also sacrificial protection
raw materials in the blast furnace
haematite- iron ore
coke- carbon
limestone- calcium carbonate
hot air in at the bottom
step 1 of blast furnace
coke burns in air to form carbon dioxide
C+O2-> CO2
carbon is being oxidised
step 2 of blast furnace method
carbon dioxide reacts with more coke to create carbon monoxide
CO2+C-> 2CO
step 3 of blast furnace
-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
step 4 of blast furnace
limestone thermally decomposes to form calcium oxide and carbon dioxide
CaCO3-> CaO+ CO2
step 5 of blast furnace
-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
how is iron removed from the blast furnace
iron is removed by the tap at the bottom of the furnace as it’s a molten liquid
reducing iron furnaces process cost
recycle iron- doesn’t pollute and cheaper
hot gases-heat trapped and used to heat blasts of hot air into furnace
environmental problems of blast furnace
-CO2 produced causing global warming
-CO produced which is a toxic gas
-Noise and dust pollution
why is iron/steel so widely used for construction?
it’s strong
