Extraction of Metals Flashcards

1
Q

What is an ore?

A

A natural substance that a metal can be economically extracted from

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2
Q

Which types of metals are often found in ores?

A

Sulfides or oxides

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3
Q

Why is sulfur dioxide bad?

A

It causes acid rain which can damage limestone buildings, harm aquatic life and plants.

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4
Q

What does ‘roasting’ mean?

A

Ore is heated in plenty of air (oxygen)

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5
Q

What is reduction?

A

Gain of electrons

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6
Q

What is a reducing agent?

A

Something that donates electrons and gets oxidised

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7
Q

What is oxidation?

A

Loss of electrons

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8
Q

What is an oxidising agent?

A

Something that accepts electrons and gets reduced

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9
Q

Balanced equation of the reduction of iron(III) oxide using carbon monoxide

A

Fe2O3 (s)+ 3CO(g) → 2Fe(l)+ 3CO2 (g)

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10
Q

Where does the reduction of metal oxides take place in?

A

Blast furnace

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11
Q

What do the roman numerals after an element show? E.g. Copper(II) oxide

A

The oxidation state of that element in that particular compound

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12
Q

Define oxidation state (AKA oxidation number)

A

Total number of electrons an element has donated or accepted

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13
Q

Balanced equation of the reduction of manganese(IV) oxide using carbon (as coke)

A

MnO2 (s) + C(s) → Mn (l) + CO2 (g)

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14
Q

Why is carbon not used for the reduction of aluminium?

A

Aluminium is too reactive and requires very high temperatures for the reduction, making it too expensive

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15
Q

How is aluminium extracted from its ore?

A

Electrolysis

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16
Q

Why does the electrolyte have to be a liquid?

A

So the ions are free to move

17
Q

What happens at the anode?

A

Oxide ions lose electrons and are oxidised, producing oxygen gas

18
Q

Why is the anode frequently replaced?

A

Because the carbon reacts with the oxygen produced

19
Q

Write the half equation of aluminium at the cathode during electrolysis

A

Al3+ + 3e- → Al

20
Q

Why is carbon not used to extract titanium?

A

Because you get titanium carbide, ruining its purity and properties

21
Q

How is titanium extracted from its ore?

A
  1. Ore is converted to TiCl4 at about 900°C using C and Cl gas
  2. TiCl4is purified by fractional distillation
  3. Cl gas gets reduced in furnace at almost 1000°C with a more reactive metal
22
Q

Write the two equations/steps of extracting titanium using magnesium

A

1) TiO2 (s) + 2Cl2 (g) + 2C (s) → TiCl4 (g) + 2CO(g)
2) TiCl4 (g)+ 2Mg(l) → Ti(s) +2MgCl2 (l)

23
Q

Why is inert atmosphere argon used in the blast furnace?

A

To prevent TiCl4, reducing agent and titanium metal from reacting with O2 or water vapour from the air

24
Q

Balanced equation of the extraction of tungsten

A

WO3 (s) +3H2 (g) → W(s) + 3H2O(g)

25
Q

Why is carbon not used to extract tungsten?

A

Because it can leave impurities, making the metal more brittle

26
Q

Problem with using hydrogen in a blast furnace?

A

Hydrogen is highly explosive when mixed with air

27
Q

Temperature for the reduction of MnO2?

A

About 1200°C (much higher than iron(III) oxide)