Redox, Rusting And Iron Flashcards

1
Q

What is Reduction? (3)

A

A reaction in which a substance either:

  • gains electrons
  • gains hydrogen
  • loses oxygen
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2
Q

What is Oxidation? (3)

A

A reaction in which a substance either:

  • loses electrons
  • loses hydrogen
  • gains oxygen
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3
Q

What is a redox reaction? (3)

A
  • When oxidation and reduction occur
  • at the same time
  • in the same reaction
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4
Q

What is the chemical name and formula for rust?

Also, what is its appearance?

A
  • Hydrated Iron (III) Oxide
  • Fe2O3 . XH2O
  • flakey orange-brown solid
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5
Q

What conditions are needed for rusting to occur? (2)

A
  • water
  • oxygen
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6
Q

What apparatus can be used to demonstrate the conditions for rusting in Iron?

A
  • 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
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7
Q

What methods can be used to prevent rusting?

A
  • plastic coating
  • painting
  • oiling
  • galvanising
  • sacrificial protection
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8
Q

How is sacrificial protection used to prevent rusting of Iron? (2)

A
  • water and oxygen reacts with a more reactive metal e.g. Zinc
  • this coats the Iron
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9
Q

What is the common name for iron ore?

A

Haematite

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10
Q

What raw materials are used in a blast furnace?

A
  1. Haemitite
    - Iron (III) Oxide = chemical name
    - Fe2O3 = Formula
  2. Coke
    - Carbon = chemical name
    - C = Formula
  3. limestone
    - Calcium Carbonate = chemical name
    - CaCO3
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11
Q

In a blast furnace, how is the reducing agent made?

A

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

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12
Q

How is haemitite (Iron (III) Oxide) reduced to form Iron?

What type of reaction is this?

A

3CO + Fe2O3 —> 2Fe +3CO2

(Carbon monoxide acts as the reducing agent)

Redox reaction: Oxygen lost by Iron (reduction), gained by Carbon Monoxide (oxidation)

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13
Q

Explain the reactions involved in removing acidic impurities in a blast furnace.

A
  1. Thermal decomposition of Calcium Carbonate (Limestone)
    HEAT
    - CaCO3 —> CO2 + CaO
  2. Calcium Oxide + Silicon Dioxide —> Calcium Silicate (Slag)
    - CaO + SiO2 —>CaSiO3
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14
Q

How are Iron and Slag removed in a blast furnace?

A
  • Both are in molten form
  • Iron is more dense than Slag
  • Slag floats above Iron, both can be tapped off
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15
Q

What is the pneumonic for remembering how oxidation and reduction occur (electrons and hydrogen only)

A

Oxidation
Is
Loss
Reduction
Is
Gain

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16
Q

Describe Phytomining (4)

A
  • 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
17
Q

What are the 3 main advantages of pytomining?

A
  • Avoids noise and dust pollution
  • Produces energy when plants are burned
  • Uses no energy transporting any rocks
18
Q

What are the 2 main disadvantages of pytomining?

A
  • It is a very slow process
  • It is seasonal
19
Q

What are the observations for the reaction between iron and copper sulphate? (2)

A
  • blue solution fades
  • red-brown solid deposited