Redox, Rusting And Iron Flashcards
What is a redox reaction?
A reaction where oxidation and reduction occurs at the same time
What is Oxidation?
Gain of oxygen, loss of hydrogen or loss of electrons
What is Reduction?
Loss of oxygen, gain of hydrogen, or gain of electrons
How do you answer questions asking “what is oxidised/reduced”
The answer will always be on the left hand (reacting) side of the equation
What is rust?
Hydrated iron(III) oxide
Fe2O3.xH2O
What is galvanising? Why is it used?
A process that bonds a layer of zinc onto the surface of steel
The zinc reacts with the air forming a protective layer over the iron.
This can also be done by attaching a chunk of a more reactive metal like zinc or magnesium to a steel structure, as this will react before the iron does. This is called sacrificial protection.
Label a diagram of a blast furnace.
Ok.
What is the first stage of iron production?
Formation of reacting agent (carbon monoxide)
Hot air (oxygen) is blown in at the base of the furnace and coke burns to heat the furnace to 1500C forming carbon dioxide
C(s) + O2(g) -> CO2
The carbon dioxide reacts with more coke to carbon monoxide
CO2(g) + C(s) -> 2CO(g)
What is the second stage of iron production?
Reduction of iron oxide to iron
The carbon monoxide reduces the iron oxide to iron. Carbon monoxide is the reducing agent.
Fe2O3(s) + 3CO(g) -> 2Fe(l) + 3CO2(g)
What is the third stage of iron production?
Removal of the impurity
The main impurity of iron ore is sand. The limestone added thermally decomposes to calcium oxide.
CaCO3(s) -> CO2(g) + CaO(s)
Calcium oxide combines with sandy impurities (silicon dioxide), in the iron ore to form slag (calcium silicate).
CaO(s) + SiO(s) -> CaSiO3(l)
What is slag?
Calcium silicate. Less dense than iron, so it floats on top of it during production.
Slag is used to make roads, landfill and building foundations.
What are some uses of iron?
Cheap, abundant metal. Used in many structures due to its strength.
