Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Chemistry❌ > SC10-11-12-13 > Flashcards

SC10-11-12-13 Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Chemistry flashcards Periodic Table flashcards Chemistry 101 flashcards Organic Chemistry 101 flashcards
1
Q

What is electrolysis?

A

The breaking down of a substance using electricity.

An electric current is passed through an electrolyte causing it to decompose.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What occurs in electrolysis?

A

Oxidation
Reduction

OIL - RIG

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What happens to the positive ions in electrolysis?

A

The positive ions (cations) in the electrolyte move towards the cathode (negative electrode) and are reduced (gain electrons).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is a cathode and anode?

A

Cathode = negative electrode.

Anode = positive electrode.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are cations and anions?

A

Cations = positive ions

Anions = negative ions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What happens to the negative ions in electrolysis?

A

The negative ions (anions) in the electrolyte move towards the anode (positive electrode) and are oxidised (lose electrons).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Why cant an ionic solid be electrolysed?

A

Because the ions are in fixed positions and cant move.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Why can a molten ionic compound be electrolysed?

A

Because the ions can move freely and conduct electricity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are positive metal ions reduced to?

A

Metal atoms at the cathode.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are negative ions oxidised to?

A

Atoms or molecules at the anode.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the reactivity series?

A

Its a table that lists metals in order of their reactivity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the elements in the reactivity series of metals?

A 
Potassium - please 
Sodium - stop
Calcium - calling 
Magnesium - me 
Aluminium - a
(Carbon) - crazy 
Zinc - zebra 
Iron - I 
Tin - totally 
Lead - like
Copper - chewing 
Silver - stripey 
Gold - grass
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the pattern in the metal reactivity series?

A

Most reactive - least reactive

Least resistant to oxidisation - most resistant to oxidisation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does potassium, sodium and calcium form when they react with cold water?

A

Hydrogen and metal hydroxide.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What happens when K, Na and Ca react with acid?

A

React violently.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What forms when magnesium, aluminium, zinc and iron react with water?

A

Reacts slowly

Reacts with steam to form hydrogen and metal oxide.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What forms when magnesium, aluminium, zinc and iron react with acid?

A

Form hydrogen and a salt solution.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is a redox reaction?

A

A reaction where oxidation and reduction occur.

Displacement.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What happens in displacement reactions?

A

A more reactive element reacts to take the place of a less reactive element in a compound.
In metal displacement reactions, the more reactive metal loses electrons and the less reactive metal gains electrons.
So the more reactive metal is oxidised and the less reactive is reduced (redox).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is a metal ore?

A

Its a rock which contains enough metal to age it economically worthwhile extracting the metal from it.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How can metals be extracted from ores?

A

Reduction with carbon
Electrolysis
Bioleaching
Phytoextraction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How do you know what method of extraction to use?

A

If its higher than carbon in the reactivity series then electrolysis.

If its below carbon than reduction with carbon.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How does electrolysis work?

A

Once the metal ore is melted, an electric current is passed through it.

The metal is discharged at the cathode and the non-metal at the anode.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are the pros and cons of extraction methods?

A

Electrolysis uses large amounts of electricity, so it expensive. There are also costs involved with melting or dissolving the ore.

Reduction with carbon is much cheaper, as carbon is cheap and also acts as a fuel to provide the heat needed for the reaction to happen.

This generally means the less reactive the cheaper it is to extract.

25
Q

What are the biological methods of extracting metal?

A

Bioleaching

Phytoextraction

26
Q

What does bioleaching involve?

A 
This uses bacteria to separate metals from their ores. The bacteria get energy from the bonds between the atoms in the ore, separating out the metal from the ore in the process. 
The leachate (solution produced by the process) contains metal ions, which can be extracted (e.g - by electrolysis).
27
Q

What does phytoextraction involve?

A

It involves growing plants in soil that contains metal compounds. The plants cant use or get rid of the metals so they gradually build up in the leaves.
The plants can be harvested, dried and burned in a furnace.
The ash contains metal compounds from which the metal can be extracted by electrolysis or reduction with carbon.

28
Q

Why are traditional methods of mining bad?

A

Damage the environment.

The new methods have a much smaller impact, but the disadvantage is that they’re slow.

29
Q

What are the advantages of recycling?

A 
Saves natural resources 
Doesn’t produce waste 
Its cheaper 
Saves energy 
Less pollution 
Doesn’t damage the environment 
Natural reserves of metal ores will last longer.
30
Q

Why does recycling materials save energy?

A

It saves energy as this process often only uses a small fraction of the energy needed to extract and refine the material from scratch.

31
Q

What are the disadvantages of recycling?

A

Costs and energy used in collecting, transporting and sorting.

Sometimes it can be more expensive and requires more energy to recycle than extract.

32
Q

What is a life cycle assessment (LCA)?

A

An LCA loos at each stage of the life of a product.

It works out the potential environmental impact of each stage.

33
Q

What are the 4 stages of the LCA?

A

Choice of material
Manufacture
Product use
Disposal

34
Q

What happens in the first stage of LCA?

A

Choice of material -
1. Metals have to be mined and extracted from their ores. These processes need a lot of energy and cause a lot of pollution.

  1. They also have to process the raw materials.
35
Q

What happens in the second stage of LCA?

A

Manufacture - packaging + product

  1. Manufacturing products uses a lot of energy and other resources.
  2. It can also cause a lot of pollution.
  3. You also need to think about any waste products and how to dispose of them.
  4. Some waste can be recycled and turned into other useful chemicals, reducing the amount that ends up polluting the environment.
  5. Some need water - businesses have to make sure they don’t put polluted water back into the environment at the end of the process.
36
Q

What happens in the third stage of LCA?

A

Product use - using them can damage the environment too

  1. Paint gives of toxic fumes
  2. Boring fuel releases greenhouse gases and other harmful substances.
  3. Fertilisers can leach into streams and rivers and cause damage to ecosystems.
37
Q

What happens in the forth stage of LCA?

A

Disposal of product -

  1. Products are often disposed of in a landfill site at the end of their life.
  2. This takes up space and can pollute land and water.
  3. Products might be incinerated, which causes air pollution.
38
Q

What is a reversible reaction?

A

Its one where the products can react with each other to produce the original reactants.

In other words it can go both ways.

39
Q

Give an example of a reversible reaction?

A

Haber process

40
Q

What is equilibrium?

A

After a while the forward reaction will be going at exactly the same rate as the backward reaction.

41
Q

What is dynamic equilibrium?

A

At equilibrium both reactions are still happening but there’s no overall affect.

The forward and backward reactions are both happening at the same time and at the same rate, and the concentration of reactants and products have reached a balance and won’t change.

42
Q

What three things can change the positions of the equilibrium?

A

Temperature
Pressure
Concentration

43
Q

What does the position of the equilibrium do?

A

Changes the amount of products and reactants present at equilibrium.

44
Q

How does temperature affect equilibrium position?

A

If you decrease the temperature, the equilibrium will move in the exothermic direction to produce more heat.

If you increase the temperature, the equilibrium will move in the endothermic direction to absorb the extra heat.

45
Q

How does pressure affect equilibrium position?

A

If you increase the pressure, the equilibrium will move towards the side that has fewer moles of gas to reduce pressure.

If you decrease the pressure, the equilibrium will move towards the side that has more moles of gas to increase pressure.

46
Q

How does concentration affect equilibrium position?

A

If you increase the concentration of the reactants, the equilibrium will move to the right to use up the reactants (making more products).

If you increase the concentration of the products, the equilibrium will move to the left to use up the products (making more reactants).

Decreasing the concentration will have the opposite affect.

47
Q

Where are transition metals found in the periodic table?

A

They sit in the middle

48
Q

What are the physical properties of transition metals?

A

Malleable
Ductile - stretched to make thin wires.
Good conductors of electricity and heat.
Shiny, strong and hard
Transition metals compounds are usually coloured.
High melting points (except from mercury, which is liquid at room temp).

Make good catalysts.

49
Q

What are alloys?

A

Its a mixture of at least two metals (or carbon).

50
Q

Why are alloys used and how does it work?

A

Some metals are aren’t strong enough for certain uses, where as alloys are stronger.

The different sized atoms disrupt the normal structure, making it harder for the layers to slide each other.

51
Q

What are some examples of alloys?

A

Bronze = copper + tin (medal, decorative ornaments, statues)
Brass = copper + zinc (water taps)
Gold alloys are used to make jewellery
Aluminium alloys are used to make aircraft
Steel = iron + carbon (bridges, engine parts, cutlery, pans ,ships, tools, cars)

52
Q

What type of reaction is rusting?

A

Redox

53
Q

What can cause metal to corrode?

A

In the presence of oxygen and water to form their metal oxides.

54
Q

What is corrosion?

A

Its a gradual chemical reaction which involves the surface of a metal changing from an element to a compound.

55
Q

How can you prevent rust?

A
  1. Painting - prevents air+water coming into contact.
  2. Grease - provides a barrier. Can also be a lubricant.
  3. Coat in plastic - provides a barrier.
  4. Galvanising - coat it in zinc to protect iron/steel.
  5. Alloying - mixing iron with other metals.
56
Q

What is electroplating?

A

Applying a metal coating to an object.

57
Q

Why is electroplating done?

A

To prevent corrosion.

To improve the appearance.

58
Q

What happens in electroplating?

A
  1. The cathode is the object you’re going to electroplate, and the anode is the bar of metal you’re using for the plating.
    Your electrolyte is a solution containing metal ions of the metal you’re plating.

Chemistry❌ (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions