Metals Flashcards

1
Q

What is the reactivity series

A
Potassium
Sodium 
Lithium
Calcium
Magnesium 
Aluminium
(Carbon)
Zinc
Iron
lead
(Hydrogen)
Copper
Silver
Gold
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2
Q

How is the reactivity series ordered

A

Most Reactive –> Least Reactive

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3
Q

What do metals lose when react with other substances

A

metal atoms lose electrons to form positive ions

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4
Q

How does the reactivity of a metal affect its reactions

A

More vigorous reactions and more easily it loses electrons it reactions to form positive ions

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5
Q

What happens if a metal higher on the reactivity series reacts with a metal lower than it

A

A metal higher on the reactivity series can displace a less reactive metal from its compounds

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6
Q

How stable is a reactive metal’s compound

A

The more reactive a metal the more stable its compounds as the bonds holding it together are very strong

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7
Q

What is the equation for when metal reacts with water

A

Metal + water –> metal hydroxide + hydrogen

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8
Q

Write the reaction of sodium and water

A

Sodium + water → sodium hydroxide + hydrogen

2Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g)

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9
Q

With what metals does water react with

A

all the metals above zinc

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10
Q

What happens when a metal reacts with an acid

A

• Metal + acid –> salt + hydrogen (g)

redox reaction as metal is being oxidised and hydrogen reduced

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11
Q

What metals react with acids

A

all above hydrogen except zinc and iron usually slowly

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12
Q

How do you test for presence of hydrogen gas

A

Lit splint in test tube should make squeaky pop noise

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13
Q

When is hydrogen produced in metals reactions

A

Always made when a metal reacts with water or a dilute acid

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14
Q

How do metals react with oxygen

A

Metal + Oxygen  Metal oxide

oxidation reaction

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15
Q

Define oxidation

A

gain of oxygen and loss of electrons

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16
Q

Define reduction

A

loss of oxygen and gain of electrons

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17
Q

What is a pneumonic for remembering oxidation and reduction

A

OILRIG
Oxidation Is Loss
Reduction Is Gain

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18
Q

What are some examples of redox ractions

A

electrolysis reactions and displacement reactions

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19
Q

What are displacement reactions

A

A displacement reaction is when a more reactive metal replaces a less reactive metal in a compound.

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20
Q

Where is carbon in the reactivity series

A

Above zinc

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21
Q

Where is hydrogen in the reactivity series

A

Above copper

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22
Q

What is a pneumonic to remember the reactivity series

A
Please                             
Send 
Charlies
Monkeys
And
Zebras
In 
Large 
Cages
Securely 
Guarded 
Potassium
Sodium 
Calcium
Magnesium 
Aluminium
(Carbon)
Zinc
Iron
lead
(Hydrogen)
Copper
Silver
Gold
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23
Q

What is an ionic equation

A

An equation where you have taken the spectator ions out

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24
Q

What are spectator ions

A

ions that are on both sides of the equation and do not contribute to the reaction

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25
Q

Here is an example of a redox displacement reaction

A

A balanced equation for the reaction between magnesium and copper sulphate solution can be written in terms of the ions with spectator ions taken out:

Mg(s) + Cu2+(aq) → Mg2+(aq) + Cu(s)

This equation is an example of a balanced ionic equation. It can be split into two half equations:

Mg(s) → Mg2+(aq) + 2e- (oxidation)
Cu2+(aq) + 2e- → Cu(s) (reduction)

Notice that:
• magnesium atoms lose electrons - they are oxidised
• copper ions gain electrons - they are reduced
• Also notice that no electrons disappear or are made they are always balanced or transferred

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26
Q

What are the steps for a half equation

A
  1. Write down the reactant and the product.
  2. Balance the atoms.
  3. Write the total charge underneath each species in the equation.
  4. Balance the charge by adding electrons.
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27
Q

What form are most metals found in

A

Combined with other elements to form compounds (ores)

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28
Q

Define an ore

A

a rock that contains enough of a metal to make extracting the metal worthwhilr

29
Q

How does the reactivity of metals determine the method of extraction

A
  • Metals above carbon must be extracted during electrolysis

- Metals below carbon must be extracted from the ore by reduction using carbon,coke or charcoal

30
Q

What is special about gold or silver

A

They are native but chemical reactions may be needed to remove elements that might contaminate it

31
Q

How is iron extracted

A
  • Iron (III) oxide is reduced to molten iron when it reacts with carbon. One of the products is carbon monoxide:
  • iron (III) oxide + carbon → iron + carbon monoxide
  • Fe2O3(s) + 3C(s) → 2Fe(l) + 3CO(g)
32
Q

Why is heating a metal with carbon preferred to electrolysis

A

It is much cheaper than using electrolysis

33
Q

How is aluminium extracted

A

extracted from bauxite :

2Al2O3 –> 4Al + 3O2

34
Q

What happens at the positive anode in electrolysis of aluminium

A
  • O2 ions are oxidised: 2O2-  2O2- + 4e-

- Oxygen reacts with carbon electrodes to form CO2 gas

35
Q

What happens at the negative electrode in electrolysis of aluminium

A
  • Al3+ gains 3 electrons as it is reduced:

- Al3+ + 3e- –> Al

36
Q

How is copper oxide extracted

A

By heating it with carbon it is reduced:

Copper oxide + carbon → copper + carbon dioxide

37
Q

What is phytomining

A

• Plants absorb metal ions through their roots the plants are then burnt to produce ash which contains a reasonable concentration of copper in it

38
Q

What are the steps for phytomining

A

1) Plants are used to absorb metal compounds such as copper(II) compounds
2. The plants are harvested, then burned to produce ash, which contains the metal compounds
3. An acid is added to the ash to produce a solution containing dissolved metal compounds (leachate)
4. Copper can be obtained from these solutions by displacement using scrap iron

39
Q

What is bioleaching

A

extraction of copper using bactera by producing acidic leachate solutions that contain the metal compounds that are desired

40
Q

What are the advantages and disadvantages of bioleaching

A
  • cheap and simple
  • eco-friendly
  • can be used on low quality ores
  • doesnt need high temp.
  • very slow compared to smelting
  • toxic chemicals produced
  • efficiency is very low; lots of waste
41
Q

How is the leachate purified

A

using scrap iron it displaces copper (cost-effective)

iron + copper(II) sulfate → iron(II) sulfate + copper

42
Q

How is copper purified

A

Copper is purified by electrolysis, electricity is passed through solutions containing copper compounds

43
Q

What are the anode and cathode made of in purification of copper

A

anode is made from impure copper

cathode is made from pure copper

44
Q

What happens to the anode and cathode in purification of copper

A

The anode loses mass as copper dissolves and the cathode gains mass as copper is deposited

45
Q

What are the half equations of the purification of copper

A

anode: Cu → Cu2+ + 2e- (oxidation)
cathode: Cu2+ + 2e- → Cu (reduction)

46
Q

Define an alloy

A

a mixture (a substance containing elements that aren’t chemically bonded) of a metal and other elements

47
Q

What are softer alloys or pure elements

A

generally pure elements

48
Q

Why are pure elements generally softer

A

As pure metals are ordered in positive regular lattices that can easily deform due to layers passing over each other

49
Q

Why are alloys harder than pure elements

A
  • Different sized particles
  • Lattice structure is disrupted
  • So fewer regular layers
50
Q

What are memory shape alloys

A

an alloy that when bended can still go back to its original shape

51
Q

Name 8 well known alloys and the elements they are made up of

A
  • High – Carbon steel : Fe, C (more brittle/ strong)
  • Low – Carbon Steel : Fe, C (less brittle/ strong)
  • Stainless Steel : Fe, Cr, Ni (resists corrosion)
  • Bronze : Cu, Sn
  • Solder: Sn, Pb
  • Brass: Cu , Zn
  • Jewellery Gold : Au, Cu , Zn
  • Stirling Silver: Ag , Zn
52
Q

Name the different alloys of Gold

A
  • 24 Karat Gold. 100% Gold
  • 18 Karat Gold. 75% Gold
  • 12 Kt. Gold 50% Gold
  • 6 Kt. Gold 25% Gold
53
Q

Define metallic bonding

A

Metallic Bonding is ‘the electrostatic attraction between a lattice of positive ions surrounded by delocalised electrons

due to the sharing of delocalised electrons

54
Q

Why do metals conduct electricity

A

electron cloud is mobile so electrons move freely

55
Q

Why are metals malleable (can be hammered or bent into shape)

A

this is due to the regular layers being able to slip over each other

56
Q

What happens to metals when they are melted

A

the forces between the metal cations and the delocalised electrons must be broken

57
Q

Why do metals have very high melting points

A

strong electrostatic forces of attraction need to be broken which require a lot of energy

58
Q

Define ductile

A

can be drawn into wires

59
Q

What is the opposite of malleable

A

brittle

60
Q

What is rusting

A

Type of corrosion; oxidation between only iron, oxygen and water

61
Q

What is the equation for rusting

A

4Fe(s) + 3O2 (g) + 2H2O (g)  2Fe2O3 + H2O

iron + oxygen + water –> Hydrated Iron (III) Oxide

(orange brown substance seen on surface of rusty objects)

62
Q

Define corrosion

A

destruction of materials by chemical reactions with substances in the environment, typically oxygen

63
Q

How can corrosion be prevented

A

greasing, Painting, and coating with plastic

64
Q

How does aluminium prevent corrosion

A

Layer of aluminium oxide to protect metal from further corrosion

65
Q

What is sacrificial coating

A

coatings that are more reactive than the metal is so it is corroded rather than the metal its protecting

66
Q

What is an example of sacrificial coating

A

zinc is used to galvanise iron

67
Q

Define electroplating

A

involves using electrolysis to put a thin layer of a metal on the object:

  • the cathode is the iron or steel object
  • the anode is the plating metal
  • the electrolyte contains ions of the plating metal
68
Q

How does electroplating prevent corrosion

A

it improves corrosion resistance