Extracting Metals And Equilibria Flashcards

1
Q

What do you observe during the displacement of copper by magnesium?

A
  • The colour of the solution will fade as blue copper sulfate is replaced by colourless magnesium sulfate
  • An orange/brown coating of copper forming on the surface of the magnesium
  • An increase in temperature as it is exothermic
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2
Q

What is phytoextraction?

A
  • Metal compounds absorbed by roots
  • Plant concentrates metal compounds in its shoots and leaves
  • Plants burned
  • Ash contains metal compounds
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3
Q

What is bioleaching?

A
  • Some bacteria break down low grade ores
  • They produce acidic solutions called leachates which contain metal ions
  • Produces toxic substances which damage the environment
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4
Q

What is the Haber process?

A
  • Nitrogen (extracted from the air) and hydrogen (obtained from natural gas) are pumped through pipes
  • A compressor increases the gas pressure to 200 atmospheres
  • The pressurised gases are heated to 450°C and passed through a reaction chamber containing an iron catalyst
  • The reaction mixture is cooled so the ammonium liquefies and can be removed
  • Unreacted nitrogen and hydrogen are recycled
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5
Q

If the temperature is increased what is the effect and the rate of reaching equilibrium?

A
  • Moves in the direction of the endothermic reaction
  • Rate increased
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6
Q

If the pressure is increased what is the effect on the rate of reaching equilibrium?

A
  • Moves in the direction of the fewest molecules of gas
  • Rate increased (if reacting gases are present)
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7
Q

If the concentration of a reacting substance increase what is the effect on the rate of reaching equilibrium?

A
  • Moves in the direction away from the reacting substance
  • Rate increased
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8
Q

If a catalyst is added what is the effect on the rate of reaching equilibrium?

A
  • The equilibrium position is not changed
  • Rate increased
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9
Q

What is the order of reactivity?

A

Potassium
Sodium
Calcium
Magnesium
Aluminium
Zinc
Iron
(Hydrogen)
Copper
Silver
Gold

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10
Q

Metal + steam >

A

Metal oxide + hydrogen

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11
Q

Metal + water >

A

Metal hydroxide + hydrogen

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12
Q

Metal + acid >

A

Salt + hydrogen

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13
Q

In the reactions between metals and water/steel/acids, are the metals oxidised or reduced? Is the water oxidised or reduced?

A

Metal – oxidised
Water – reduced

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14
Q

How does a metals reactivity relate to its tendency to form cations?

A

The higher up a metal is in the reactivity series, the greater the tendency to form cations

The lower down the metal is, the greater it’s resistance to oxidation

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15
Q

Which metals react with water?

A

Potassium
Sodium
Calcium

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16
Q

Which metals react with dilute acid?

A

All but copper silver and gold

17
Q

What is oxidation in terms of oxygen?

A

Gain of oxygen

18
Q

What is reduction in terms of oxygen?

A

Loss of oxygen

19
Q

Where are most unreactive metals found?

A
  • In the earths crust
  • As uncombined elements
20
Q

What is an ore?

A

A rock that contains enough of a metal or metal compound to make extracting it worthwhile

21
Q

Which metals can be extracted by reduction of carbon?

A
  • Metals are less reactive than carbon
  • Zinc iron copper
22
Q

What equipment is used to extract iron?

A

Blast furnace

23
Q

What is the equation for the reduction of iron oxide by carbon?

A

Iron oxide + carbon > iron + carbon monoxide

Or

Iron oxide + carbon monoxide > iron + carbon dioxide

24
Q

How is aluminium extracted?

A

Electrolysis:

  • Aluminium is dissolved in molten cryolite
  • At the cathode, aluminium ions gain electrons and are reduced to aluminium atoms
  • At the anode, oxide ions lose electrons to form oxygen gas
  • Oxygen reacts with the carbon anodes so they must be replaced regularly
25
Q

What are the advantages of recycling metals?

A
  • Requires less energy than it does to extract new ones
  • Metal ores will last longer
  • Fewer quarries and mines
  • Less noise and heavy traffic
  • Less land is needed
26
Q

What are the disadvantages of recycling?

A
  • Used metals must be collected and transported to the recycling centre
  • Different metals must be removed from used items and sorted
27
Q

What are the stages of life-cycle assessments?

A
  • Extracting and processing raw materials
  • Manufacturing and packaging
  • Use and operation during its lifetime
  • Disposal
28
Q

What data do you need for an LCA?

A
  • Use of energy and water
  • Release of a waste materials
  • Transport and storage
  • Whether the raw material is renewable or nonrenewable
  • Whether any of the products can be recycled or reused
  • How the product will be disposed
29
Q

What is dynamic equilibrium?

A
  • When the rate of forward reaction is equal to the rate of backward reaction
  • So the concentration of reactants and products are constant even though they are continually reacting
30
Q

What is the Haber process?

A

The reversible reaction between nitrogen and hydrogen and form ammonia

31
Q

What are the main stages of the Haber process?

A
  • Nitrogen (from air) and hydrogen (from natural gas) are pumped through pipes
  • A compressor increases the gas pressure to 200 atmospheres
  • The gas is then heated to 450°C and passed through a reaction chamber containing an iron catalyst
  • The mixture is cooled so the ammonia liquefies and is removed
  • Unreacted nitrogen and hydrogen are recycled
32
Q

If the temperature increases, what will be the effect on the equilibrium position?

A

It will move in the direction of the endothermic reaction

33
Q

If the pressure is increased what will be the effect on the equilibrium position?

A

It will move in the direction of the fewest molecules of gas

34
Q

If the concentration of a reacting substance is increased, what will be the effect on the equilibrium position?

A

It will move in the direction away from the reacting substance