Redox , Rusting and Iron

3 definitions of oxidation

1. The gain of oxygen by a substance

2. The loss of hydrogen from a substance

3. The loss of electrons from a substance (OIL)

3 definitions of reduction?

1. The loss of oxygen from a substance

2. The gain of hydrogens by a substance

3. The gain do electrons by a substance ( RIG)

element combining with oxygen oxidation example

magnesium + oxygen → magnesium oxide

bright white light, forms white solid

2Mg + O₂ →2MgO

sulfur + oyxgen -. sulfur dioxide

S + 0₂ → S0₂

_{the yellow solid sulfur melts to a red liquid} which burns with a blue flame _{releasing heat and a colourless pungent and chocking gas called sulfur dioxide}

combustion of fuels

oxygen is added and an oxide is produced, heat is also released

Carbon + oyxgen → carbon dioxide

C +0₂ → CO₂

_{Black carbon (charcoal) is burned in a plentiful supply of oxygen and a colourless gas is formed}

reduction reaction example

chlorine + hydrogen → hyrdogen chloride

Cl₂ + H₂ → 2HCl

reduction is gain of hydrogen, chlorine gains hydrogen therefore chlorine has been reduced

what is redox

A redox reaction involves both oxidation and reduction in the same reaction

what colour is copper oxide

black soild

what colour is copper

pink-brown solid

copper oxide reduction

CuO + H₂ → Cu + H₂0

hyrdogen isg gaining oxygen so its oxidation

copper is losing oxygen soits reduction

the both make redox

Balance symbol equation :

Zn + CuSO₄ → Cu + ZnSO₄

Ionic Equation :

Zn + Cu²⁺ → Cu +Zn²⁺

Why does the sulfate ion not appear

becuase it is a spectator ion

Balance symbol equation :

Zn + CuSO₄ → Cu + ZnSO₄

Ionic Equation :

Zn + Cu²⁺ → Cu +Zn²⁺

What type of reaction is this

Redox because zinc is losing electrons- oxidation and copper ion is gaining electrons electrons to become a copper atom - reduction

How does rusting occur

iron and steel rust when it comes into contact with oxygen and water

What type of reaction is rusting

Oxidation and is a form of corrosion

Rusting chemical name

Hydrated iron (III) oxide

describe what rust looks like

red-brown flaky solid

word equation for rust

iron + water + oxygen → hydrated iron (III) oxide

Test Tube	Present	Rusting observed	Reason
A
B
C
D

Test Tube	Present	Rusting observed	Reason
A	Ox, Wa, Fe	Yes	all present
B	No ox, Wa, Fe	No	no oxygen
C	Ox, Wa , Fe	Yes	all present
D	Ox, No wa, Fe	No	calcium chloride removed water

difference between corrosion and rusting

corrosion is the reaction of any metal with air(oxygen) / rusting is the speicific name given to the corrosion of iron/steel

1 method of preventing rust

1. Barrier method - preventing water and oyxgen from reaching ron , painting, oiling, plastic coasting e.g Cars, bridges, bicycle chains

2nd way of preventing rust

Metal covering/ plating - cover with another thin layer metal using electroplating. Acting as a barrier. E.g food cans are covered in tin (non reactive, non toxic), chromium used for car for shiny

What is galvanising

Galvanising involves iron being coated with zinc. E.g buckets/ chains are often galvanised

How does sacrifical protection work?

Iron is coated with a more reactive metal e.g magnesiumor a more reactive metal is attached to iron. This reacts instead of the iron with oxygen/ water.

Why is iron important

Used in bridges and structures due to its strength, cheap metal and abundant.

Purpose of blast furnace

to extract pure iron from iron ore and acidic sand impurities

Chemical name for iron ore, and formula

Haematite , Iron (III) Oxide, Fe₂ O₃

What are the raw materials that go into a blast furnace

Iron ore, coke(carbon), limestone (calcium carbonate)

how do u form the reducing agent

hot air converts carbon into carbon dioxide and then carbon monoxide . Exothermic reaction

formation of reducing agent formula

Carbon + oxygen → carbon dioxide

C + O₂ → CO₂

Carbon dioxide + carbon → carbon monoxide

CO₂ + C → 2CO

reduction of iron oxide to iron

carbon monoxide reduces iron oxide to iron (reduction )

reduction of iron oxide to iron formula

Iron (III) oxide + Carbon monoxide → Iron + Carbon dioxide

Fe₂O₃ +3CO → 2Fe + 3CO₂

removal of impurity

limestone undergoes thermal decomposition and the calcium oxide produced reacts with the acidic impurities e.g sand/silicon dioxide) to produce molten slag. This falls to the bottom of the furnace ( used for tar road) . Molten iron is denser so it sinks below the slag. They are tapped off the base

removal of impurity formula

Calcium carbonate → calcium oxide + carbon dioxide

CaCO₃ → CaO + CO₂

Calcium oxide + silicon dioxide → Calcium sillicate

CaO + SiO₂ → CaSiO₃