Section 5 - Pgs 70 - 77 Flashcards
(100 cards)
1
Q
What is crude oil?
A
A mixture of different hydrocarbons.
2
Q
What is the name for the process of separating different compounds in crude oil?
A
Fractional distillation
3
Q
How is crude oil formed?
A
Over millions of years, high temperatures and pressures cause the buried remains of plants and animals to turn into crude oil.
4
Q
How does fractional distillation work?
A
1) Crude oil is heated until most of it is a gas (except bitumen).
2) The gases enter a fractionating column, where the liquid fraction, bitumen, is drained off at the bottom.
3) In the column there is a temperature gradient (hot at the bottom, cooler at the top). The gases travel up through the column.
4) When a fraction reaches a height with a temperature lower than its boiling point, it condenses and the liquid is pumped away from that layer.
5
Q
How does the length of a hydrocarbon relate to its boiling point?
A
- Long hydrocarbon = High boiling point
- Short hydrocarbon = Low boiling point
6
Q
What prevents separated liquid from running back down the fractionating column in fractional distillation?
A
Bubble caps
7
Q
How does length of a hydrocarbon relate to colour, viscosity, boiling point and flammability of the hydrocarbon?
A
The longer the hydrocarbon,
- The darker it is
- The thicker it is
- The higher its boiling point
- The less flammable it is
8
Q
Where in the fractionating column can short and long hydrocarbons be found?
A
- Short hydrocarbons = At the top
- along hydrocarbons = At the bottom
9
Q
What are the fractions in crude oil called?
A
1) Refinery Gas
2) Gasoline (petrol)
3) Naphtha
4) Kerosene (paraffin)
5) Diesel
6) Fuel Oil
7) Bitumen
10
Q
How many carbons are in each fraction in crude oil?
A
Refinery Gas - 3 Gasoline - 8 Naphtha - 10 Kerosene - 15 Diesel - 20 Fuel Oil - 40 Bitumen - 70+
11
Q
What are the uses of refinery gas?
A
- Bottled gas
- Heating
- Used in pottery and glass manufacture
12
Q
What are the uses of gasoline?
A
- Fuel for cars
13
Q
What are the uses of naphtha?
A
Used as a ‘feedstock’ (starting material) to make:
- Plastics
- Dyes
- Drugs
- Explosives
- Paints
14
Q
What are the uses of kerosene?
A
- Airplane fuel
- Domestic heating
- Paint solvent
15
Q
What are the uses of diesel?
A
- Fuel for diesel engines in cars, trucks, trains, boats.
16
Q
What are the uses of fuel oil?
A
- Domestic central heating
- Fuel for large ships
17
Q
What are the uses of bitumen?
A
- Road surfacing
- Asphalt for roofs
18
Q
Is fractional distillation a physical process?
A
Yes, because there are no chemical reactions.
19
Q
Does fractional distillation produce enough short-chain hydrocarbons?
A
No, more are required than can be produced by fractional distillation.
20
Q
Does fractional distillation produce enough long-chain hydrocarbons?
A
Yes, it produces more than can be used directly.
21
Q
What does each fraction in fractional distillation contain?
A
A mixture of hydrocarbons with similar boiling points.
22
Q
What is the problem with burning fuels from fractional distillation?
A
They can produce pollutants when burnt.
23
Q
What 3 main pollutants are released when fuels are burned?
A
- Carbon monoxide
- Nitrogen oxides
- Sulphur dioxide
24
Q
How is carbon monoxide produced (by fuels)?
A
When hydrocarbon fuels are burnt without enough oxygen - this is incomplete combustion.
25
Why is carbon monoxide dangerous?
- It is poisonous because it combines with haemoglobin in blood cells, reducing their capacity to carry oxygen.
- A lack of oxygen can lead to fainting, a coma or even death.
26
How is sulphur dioxide produced (by fuels)?
When fossil fuels are burnt, sulphur impurities become sulphur dioxide.
27
How are nitrogen oxide fuels produced (by fuels)?
- When fuels are burnt, the temperature may be high enough for nitrogen and oxygen in the air to react.
- This often happens in car engines.
28
Give 2 examples of nitrogen oxides.
- Nitrogen monoxide (NO)
| - Nitrogen dioxide (NO2).
29
What is cracking?
The splitting of long-chain alkanes into alkenes and short-chain alkanes.
30
Why is cracking needed?
1) Long-chain alkanes like bitumen are less useful and in small demand than short-chain alkanes like petrol.
2) Alkenes are used for making plastics.
31
What is the name of the process by which long-chain alkanes are converted into alkenes and short-chain alkanes?
Cracking
32
What type of a reaction is cracking?
Thermal decomposition (the breaking down of molecules using heat).
33
In industry, how is cracking done?
- Vaporised hydrocarbons are passed over a powdered catalyst at about 600-700*C
- Catalysts: Silica (SiO2) and Alumina (Al2O3)
34
What catalysts are used in cracking?
- Silica (SiO2)
| - Alumina (Al2O3)
35
How can paraffin be cracked in the lab?
1) Place some mineral wool soaked in paraffin at the bottom of a horizontal boiling tube and some silica or alumina closer to the top.
2) Connect a delivery tube from the boiling tube to a gas jar upside-down in some water.
3) Alternate between heating the paraffin and the silica or alumina catalyst until the paraffin vaporises and the catalyst glows red.
4) The paraffin is cracked as it passes over the hot catalyst.
5) Small alkanes collect at the front of the boiling tube, while alkene gases travel through the delivery tube and are collected in the gas jar.
(Diagram pg 72)
36
How do molecule arrangements change when paraffin is heated?
See bottom of pg 72 of revision guide.
37
What is the symbol equation for the formation of naturally acidic rain?
CO2 + H2O -> H2CO3
38
What is the symbol equation for the formation of acid rain (sulphuric acid)?
2SO2 + O2 + 2H2O -> 2H2SO4
39
Why is all rain slightly acidic?
The CO2 in the air reacts with water to produce a slightly acidic solution.
40
What two pollutants can cause acid rain?
Sulphur dioxide and Nitrogen oxides
41
What are the impacts of acid rain?
- Lakes become acidic -> Plants and animals die as a result
- Kills trees
- Damages limestone buildings
- Suggested links to health problems
42
What are the two types of polymer?
- Addition
| - Condensation
43
How are plastics formed?
When lots of small monomers join to form a polymer.
44
What monomers make up addition polymers?
Alkenes (which have a double C=C bond)
45
How does addition polymerisation work?
Under high pressure and with a catalyst, thye manyu alkenes open up their double C=C bond and join to jorm very long saturated chains - polymers.
46
Remember to revise how polymers are symbolised.
Pg 73 of revision guide
47
How is the name of a polymer decided?
You just take the name of the monomer it is made from and add 'poly' to the start.
48
What polymer does ethene make?
Polyethene
49
What polymer does propene make?
Polypropene
50
What polymer does chloroethene make?
Polychloroethene
51
Remember to revise how polymers are symbolised.
Pg 73 of revision guide
52
How is the name of a polymer decided?
You just take the name of the monomer it is made from and add 'poly' to the start.
53
What polymer does ethene make?
Polyethene
54
What polymer does propene make?
Polypropene
55
What polymer does chloroethene make?
Polychloroethene
56
What is condensation polymerisation?
When two different types of monomer join and small molecules such as water are lost.
57
What is the full name for PVC?
Polychloroethene (a.k.a Polyvinyl chloride)
58
Draw a diagram for the making of nylon.
Pg 74 of revision guide OR 1st page of exercise book
59
What are the properties and uses of polyethene?
Light, stretchable polymer
| - Packaging -> Plastic bags, bottles, etc.
60
What is the best way to dispose of addition polymers?
Reuse them as many times as possible and then recycle them.
61
What are the properties and uses of polychloroethene?
Good insulator
- Clothes
- Pipes
- Insulating electric cables
62
What is the full name for PVC?
Polychloroethene (a.k.a Polyvinyl chloride)
63
Why do most addition polymers take a long time to biodegrade?
They are inert because the carbon-carbon bonds are very strong and are not easily broken.
64
Why can addition polymers not be burn to dispose of them?
They release toxic gases when burnt.
65
What is the best way to dispose of addition polymers?
Reuse them as many times as possible and then recycle them.
66
What is the Haber process?
An industrial process used to produce ammonia (NH3).
67
What is the word equation for the Haber process?
Nitrogen + Hydrogen Ammonia (+ Heat)
68
What is the symbol equation for the Haber process?
N2 + 3H2 2NH3 (+ Heat)
69
Where is the nitrogen used in the Haber process obtained from?
The air
70
Where is the hydrogen used in the Haber process obtained from?
Natural gas or from cracking hydrocarbons
71
What state is the ammonia produced in the Haber process in?
Gas, but it can be cooled in a condenser to make it a liquid.
72
What are the reasons for the catalyst used in the Haber process?
Iron increases the rate of reaction but doesn't effect the yield.
73
What are the industrial conditions for the Haber process?
Pressure: 200 atm
Temperature: 450*C
Catalyst: Iron
74
What are the reasons for the pressure used in the Haber process?
High pressures favour the forward reaction (producing ammonia), so the pressure is set as high as possible to maximise yield without exceeding cost.
75
What are the reasons for the temperature used in the Haber process?
- High temperatures favour the reverse reaction, so the temperature is lowered as much as possible to increase yield.
- However, lower temperatures mean a slower rate of reaction, so the temperature has to be increased.
- A compromise is made between the rate of reaction and yield -> This is about 450*C
76
Why is ammonium nitrate a good fertiliser?
It has nitrogen from 2 sources - the ammonia and the nitric acid.
77
What are the reasons for the catalyst used in the Haber process?
Iron increases the rate of reaction but doesn't effect the yield.
78
What are the uses of the ammonia produced in the Haber process?
- Nitric acid
| - Ammonium nitrate fertiliser
79
By which process is ammonia used to make nitric acid?
Ostwald process
80
Why are the conditions for the contact process important?
The second reaction is reversible, so the right temperature and pressure are required to maximise yield.
81
Why is ammonium nitrate a good fertiliser?
It has nitrogen from 2 sources - the ammonia and the nitric acid.
82
What is the contact process?
The process by which sulphuric acid is made?
83
What are the stages of the contact process (in words)?
1. Sulphur is burnt in air to make suphur dioxide
2. Sulphur dioxide is oxidised to form sulphur trioxide
3. Sulphur trioxide is dissolved in concentrated sulphuric acid to form liquid oleum
4. Oleum is diluted with water to form concentrated sulphuric acid
84
Give the 4 equations of the contact process.
1. S + O2 -> SO2
2. 2SO2 + O2 2SO3 (Reversible!)
3. SO3 + H2SO4 -> H2S2O7
4. H2S2O7 + H2O -> 2H2SO4
85
What are some uses of sulphuric acid?
- Fertilisers -> Mostly phosphate fertilisers
- Detergents
- Paints
86
What are the conditions for the contact process?
Temperature: 450*C
Pressure: 2 atm
Catalyst: Vanadium(V) oxide (V2O50
87
What are the reasons for the temperature in the contact process?
- The forward reaction of the reversible 2nd reaction is exothermic, so the temperature is reduced as much as possible to increase yield.
- However, to increase the rate of reaction, the temperature is increased as much as possible.
- A compensastion between yield and rate of reaction is 450*C
88
What are the reasons for the pressure in the contact process?
There are more moles on the left of the reversible reaction than on the right, meaning pressure favours the forward reaction. Therefore, 2 atm are used.
89
What are the reasons for the catalystin the contact process?
Vanadium oxide increases the rate of reaction without decreasing yield, so it is used.
90
What are some uses of sulphuric acid?
- Fertilisers -> Mostly phosphate fertilisers
- Detergents
- Paints
91
What is brine?
Sodium chloride solution
92
What are the products of the electrolysis of brine?
- Hydrogen
- Chlorine
- Sodium hydroxide
93
What is formed at the anode during the electrolysis of brine?
Chlorine
94
What is formed at the cathode during the electrolysis of brine?
Hydrogen
95
What stays in solution during the electrolysis of brine?
The sodium ions and hydroxide ions stay in the solution, forming sodium hydroxide.
96
Describe what happens during the electrolysis of brine?
Anode: Chlorine
Cathode: Hydrogen
Solution: Sodium hydroxide
97
What are some uses of chlorine produced by the electrolysis of brine?
- Sterilising water supplies
- Making bleach
- Making HCl
98
What are some uses of hydrogen produced by the electrolysis of brine?
- Haber process
| - Changing oils into fats for making margarine
99
What are some uses of sodium hydroxide produced by the electrolysis of brine?
Chemical industry:
- Soap
- Bleach
- Paper pulp
100
What are the properties and uses of polypropene?
Very tough, but flexible and heat resistant
• Kettles
• Food containers
• Carpets
