SC11 - Obtaining and Using Metals ✓ Flashcards Preview

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Flashcards in SC11 - Obtaining and Using Metals ✓ Deck (18)
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1

SC11a - List the resctivity series [with a way to remember it]

  • Pop          Potassium
  • Stars        Sodium
  • Can          Calcium
  • Make       Magnesium
  • Absolute  Aluminium
  • Crazy       (Carbon)
  • Zillions     Zinc
  • If               Iron
  • Tiny          Tin
  • Little         Lead
  • Children  Copper
  • Spend      Silver
  • Good       Gold
  • Pennies   Platinum

2

SC11a - How do potassium, calcium and sodium react with water and dilute acids?

  • Reacts with cold water to from hydrogen and metal hydroxide
  • Reacts violently with acid

3

SC11a - How do magnesium, aluminium, zinc and iron react with water and dilute acids?

  • Reacts very slowly if at all when with cold water
  • But reacts with steam to form metal oxide and hydrogen
  • Reacts with acid to form hydrogen and salt solution

4

SC11a - How do copper, silver, gold and platinum react with water and dilute acids?

They don't as they are inert in their pure form.

5

SC11a - What is a displacement reaction?

  • A reaction in which a more reactive element displaces a less reactive element from a compound.
  • e.g. Zn + CuSO4 → ZnSO4 + Cu

6

SC11a - A displacement reaction is also another type of reaction. What is this and how can you show this?

A redox reaction as the charge on the metals switch around. e.g. in Zn + CuSO4 -> ZnSO4 + Cu the ionic euation shows that Zn + Cu2+ -> Zn2+ + Cu

7

SC11b - What are the three ways you can extract metals and how do these relate to their position on the reactivity series?

  • Found uncombined in the earth's crust.
    • This applies to elements gold and lower in the reactivity series
  • Extacted by heating an ore with carbon.
    • This is for elements less reactive than carbon or else carbon can't displace it
  • Electrolysis of molten compound.
    • This is very expensive so only used for aluminium and upwards as they cannot be ehated with carbon to be extracted

8

SC11b - What is an ore?

A rock that contains enough of a metal to extract it for a profit.

9

SC11b - What are the two biological methods of extraction?

  • Phytoextraction:
    • Growing plants on lands that contain the desired matal so that they absorb it.
    • These are then burned and the metal is obtained fromt their ashes
  • Bioleaching:
    • Bacteria is grown on low-grade(uneconomical) ore.
    • This forms a leachate (solution containing the desired metal compound)
    • The copper is extracted by displacing it with scrap iron.

10

SC11b - What are the advantages and disadvantages of using bioleaching?

Pros:

  • No harmful gases produced
  • Less landscape damage than mining
  • Conserves supplies of high grade ores
  • Doesn't require high temeratures

Cons:

  • Very slow
  • Toxic substances can be produced which damage the environment

11

SC11b - What are the advantages and disadvantages of using phytoextraction?

Pros:

  • No harmful gases produced
  • Less landscape damage than mining
  • Conserves supplies of high grade ores
  • Can extract minerals from contaminated soils

Cons:

  • Very slow
  • More expensive than mining some ores
  • Plant growth is dependant on weather conditions

12

SC11c - What are oxidation, reduction and redox reactions in terms of oxygen?

  • Oxidation is the gain of oxygen
  • Reduction is the loss of oxygen
  • A redox reaction is a reaction in which a substance is oxidised and another is reduced

13

SC11c - What is corrosion?

When a metal reacts with oxygen (oxidises) making it weaker over time

14

SC11c - How is rusting different to corrosion?

Rusting occurs when iron/steel reacts with oxygen and water.

15

SC11c - Why don't some metals such as aluminium corrode very quickly, despite being very reactive?

They form a protective layer of tarnish stopping any further corrosion

16

SC11d - What are the advantages of recylcing metals?

  • Natural resources of ores will last longer
  • Less need to mine and harmful side effects from this
  • Less pollution from extraction
  • For many metals this takes less energy
  • Less waste metals at landfill sites

17

SC11d - What are the disadvantages of recycling metals?

  • Costs of energy is high to collect, transport and sort are high
  • Sometimes it is more expensive to recycle metals than to extract more

18

SC11d - What is a life cycle assessment and what are its uses?

A life cycle assessment is an assessment to work out the environmental impact of the obtaining, manufacturing, use and disposal of a product.

It can be used to work out:

  • Which materials are better to use for manufacturing
  • Whether its more beneficial to recycle or not