Redox, Rusting And Iron Flashcards
What is Reduction? (3)
A reaction in which a substance either:
- gains electrons
- gains hydrogen
- loses oxygen
What is Oxidation? (3)
A reaction in which a substance either:
- loses electrons
- loses hydrogen
- gains oxygen
What is a redox reaction? (3)
- When oxidation and reduction occur
- at the same time
- in the same reaction
What is the chemical name and formula for rust?
Also, what is its appearance?
- Hydrated Iron (III) Oxide
- Fe2O3 . XH2O
- flakey orange-brown solid
What conditions are needed for rusting to occur? (2)
- water
- oxygen
What apparatus can be used to demonstrate the conditions for rusting in Iron?
- one test tube with:
1. O2 present.
2. Anhydrous Calcium Chloride to absorb water
3. Dried air
No rusting will occur - another test tube with:
1. H2O and O2 present
2. distilled water
3. air
Rusting will occur - another test tube with:
1. Only H2O present
2. A layer of oil
3. Boiled water
No rusting will occur
What methods can be used to prevent rusting?
- plastic coating
- painting
- oiling
- galvanising
- sacrificial protection
How is sacrificial protection used to prevent rusting of Iron? (2)
- water and oxygen reacts with a more reactive metal e.g. Zinc
- this coats the Iron
What is the common name for iron ore?
Haematite
What raw materials are used in a blast furnace?
- Haemitite
- Iron (III) Oxide = chemical name
- Fe2O3 = Formula - Coke
- Carbon = chemical name
- C = Formula - limestone
- Calcium Carbonate = chemical name
- CaCO3
In a blast furnace, how is the reducing agent made?
Hot air is blasted into the furnace:
- the oxygen reacts with he coke (carbon) to form CO2 (carbon dioxide
- the carbon dioxide reacts with the coke (carbon) to form CO (carbon monoxide)
Equations:
- O2 + C —> CO2
- CO2 + C —> 2CO
How is haemitite (Iron (III) Oxide) reduced to form Iron?
What type of reaction is this?
3CO + Fe2O3 —> 2Fe +3CO2
(Carbon monoxide acts as the reducing agent)
Redox reaction: Oxygen lost by Iron (reduction), gained by Carbon Monoxide (oxidation)
Explain the reactions involved in removing acidic impurities in a blast furnace.
- Thermal decomposition of Calcium Carbonate (Limestone)
HEAT
- CaCO3 —> CO2 + CaO - Calcium Oxide + Silicon Dioxide —> Calcium Silicate (Slag)
- CaO + SiO2 —>CaSiO3
How are Iron and Slag removed in a blast furnace?
- Both are in molten form
- Iron is more dense than Slag
- Slag floats above Iron, both can be tapped off
What is the pneumonic for remembering how oxidation and reduction occur (electrons and hydrogen only)
Oxidation
Is
Loss
Reduction
Is
Gain
Describe Phytomining (4)
- Plants absorb metal compounds (e.g. Copper salts)
- The plants are harvested, then burned to produce ash, which contains the metal compounds;
- Acid (generally sulfuric acid) is reacted with the ash to produce a solution containing dissolved metal compounds (leachate);
- Metals can be obtained from these solutions by displacement with scrap iron and
What are the 3 main advantages of pytomining?
- Avoids noise and dust pollution
- Produces energy when plants are burned
- Uses no energy transporting any rocks
What are the 2 main disadvantages of pytomining?
- It is a very slow process
- It is seasonal
What are the observations for the reaction between iron and copper sulphate? (2)
- blue solution fades
- red-brown solid deposited
