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Chemistry > Topic 8/9 - Fuels and Earth Science / Separate Chemistry > Flashcards

Topic 8/9 - Fuels and Earth Science / Separate Chemistry Flashcards

1
Q

What is crude oil?

A

Complex mixture of lots of different hydrocarbons
Main source of hydrocarbons and is used as a raw material to create lots of useful substances in the petrochemical industry
Can be seperated into fractions - simpler hydrocarbons

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2
Q

Where is crude oil sourced from

A

Underground, formed over millions of years from dead plant and animal matter. Its non-renewable (finite) resource.

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3
Q

What are hydrocarbons?

A

Compounds which just contain hydrogen and carbon.

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4
Q

How are the hydrocarbons found in crude oil arranged?

A

Chain or rings and are mostly alkenes ( CnH2n+2)

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5
Q

How are the fractions in crude oil separated?

A

Fractional Distillation

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6
Q

How does fractional distillation work?

A

Oil is heated untill most of it has turned into gas. The gases enter a fractioning column ( the liquid bit, bitmuten, is drained off at the bottom)
In the column theres a temperature gradient ( hot at bottom and cooler as you go up)

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7
Q

How does fractional distillation seperate the crude oil hydrocarbons?

A

The longer hydrocarbons have higher boiling points, they turn back into liquids and drain out of the column early on, when they’re near the bottom.
The short hydrocarbons have lower boiling points, they drain much later on.

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8
Q

What is the order of hydrocarbons in fractional distillation?

A

Top - cooler - shorter chains
Gases
Petrol
Kerosene ( Parrafin )
Diesel Oil
Fuel oil - about 40
Bitmuten - 70+ hydrocarbon chains
Bottom - hotter - longer chains

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9
Q

What is bitmuten used for?

A

To surface roads and roofs

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10
Q

What is fuel oil used for?

A

Fuel for large ships and power stations

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11
Q

What is diesel oil used for?

A

Some

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12
Q

What is kerosene used for?

A

Used as fuel in aircraft

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13
Q

What is petrol used for?

A

Fuel in cars

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14
Q

What are gases used for?

A

Domestic heating and cooking

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15
Q

What is a homologous series, how do neighbouring compounds differ within it?

A

A family of molecules which have the same general formula and share similar chemical properties
The molecular formulas of neighbouring compounds differ by a CH2 unit

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16
Q

What are the 2 main types of homoglous series?

A

Alkanes and Alkenes

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17
Q

How do intermolecular forces vary in hydrocarbons?

A

The intermolecular forces of attraction break more easily in small molecules than they do in bigger molecules - forces are stronger in bigger molecules
Big molecules have higher boiling points as a result

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18
Q

Why are shorter hydrocarbons easier to ignite?

A

they have lower boiling points, and tend to be gases at room temperature.
These gas molecules mix with oxygen in the air to produce a gas mixture which bursts into flames if it comes in contact with a spark

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19
Q

Why are longer hydrocarbons harder to ignite?

A

They are usually liquids at rooms temperature. They have higher boiling points and are much harder to ignite

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20
Q

What is viscosity a mesure of?

A

how easily a substance flows

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21
Q

How does viscosity vary through hydrocarbons?

A

The stronger the force is between hydrocarbon molecules, the harder it is for liquid to flow.
Fractions with longer hydrocarbons = higher viscosity = Thick (treacle)

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22
Q

What happens when you burn hydrocarbons in oxygen?

A

Combustion reactions - why theyre good fuels

this is exothermic

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23
Q

What is complete combustion and its products?

A

Hydrocarbons burning in** plenty** of Oxygen
Only products are Carbon Dioxide and Water

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24
Q

What is incomplete combustion?

A

Hydrocarbons burning in** a limited supply** of Oxygen

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25
Q

What does incomplete combustion produce as well as carbon dioxide and water?

A

Carbon monoxide (CO) and carbon in the form of soot

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26
Q

How can carbon monoxide damage the body?

A

it can comine with red blood cells and stop blood from doing its proper job of carrying oxygen around the body - fainting, coma, death

27
Q

How can incomplete combustion damage the environment?

A

During incomplete combustion, tiny particles of carbon can be released into the atmosphere, when they fall back to the ground they form soot.
Soot makes buildings look dirty, reduces air quality, and can cause or worsen respitory problems

28
Q

How does burning fossil fuels cause acid rain?

A

When fossil fuels burn, they release mostly CO2
They also release other harmfull gases such as sulfur dioxide and various nitrogen oxides.
Sulfur dioxide comes from impurities in fossil fuels. when it mixes with the clouds, it forms dilute sulfuric acid. Then it falls as acid rain

29
Q

How does acid rain damage things?

A
  • Causes lakes to become acidic and plants/animals die as a result
  • Kills trees, damages limestone buildings, and stone statues can also cause metal corrode
30
Q

How does nitrogen oxide damage things?

A

Created from a reaction of nitrogen and oxygen in the air, caused by energy released in combustion reactions.
Contribute to acid rain and photochemical smog - air pollution that can cause breathing difficulties

31
Q

What are the pros of hydrogen gas?

Energy

A

Very clean fuel
In a hydrogen fuel cell, hydrogen comines with oxygen to produce energy, only waste product is water. Hydrogen is obtained from water - renewable rescourse

32
Q

What are the cons of hydrogen gas?

Energy

A

You need a special, expensive engine.
Expensive and often uses energy from another source
Hard to store

33
Q

What is cracking?

A

Splitting up long chain hydrocarbons
- turns long saturated ( alkane ) molecules into smaller unsaturated (alkene)
- Form of thermal decomposition
- the longer molecules produced from fractional distillation are cracked into smaller ones because theres more demand for smaller ones like petrol and diesel
- Also produces alkene molecules, which can be used to make polymers

34
Q

Thermal decomposition

A

When one substance breaks down into at least two new ones when you heat it - breaking strong covalent bonds, so you need lots of energy - catalysts are often used

35
Q

how does cracking work?

A

Vaporised hydrocarbons are passed over a powdered catalyst at about 400 C - 700 C and 70 atm
Aluminium oxide is the catalyst used. The longer molecules break up or “crack” on the surface of the catalyst used.

36
Q

How do you test for Oxygen?

A

Re-lit glowing splint

37
Q

What are alkanes ?

A

Saturated hydrocarbons
Formula : CnH2n + 2
H
I
H-C-H
I
H

(Add middle column each time)

Methane

38
Q

What are the first 4 alkanes?

A

Methane - CH4
Ethane - C2H6
Propane - C3H8
Butane - C4H10

39
Q

Why are alkanes saturated and alkenes unsaturated?

A

Alkanes have a double bond, making them unsaturated as they are able to make more bonds

40
Q

What are alkenes?

A

C=C double bond
Unsaturated
Formula - CnH2n
H H
C=C
H. H (add HCH each time)

41
Q

What are the first 3 alkenes?

A

Ethene, Propene, Butane

42
Q

What happens to hydrocarbons in combustion reactions?

A

they are oxidised

43
Q

What is the test for alkanes / alkenes?

A

Bromide water
alkene will turn orange bromide water clear, as its double bond reacts with the bromine
Alkane has no spare bonds.

44
Q

What are addition polymers made from?

A

Unsaturated monomers, these can open up their double bonds and join together to form polymer chains.

45
Q

What are polymers

A

Substances of high average relative molecular mass made by joining up lots of small repeating units called monomers. The monomers make addition polymers that have a double covalent bond

46
Q

What is a functional group?

A

A group of atoms that determine how a molecule reacts (the same in molecules of same homologous series)

47
Q

What is the functional group of alkEnes?

A

C=C

48
Q

What are the products of complete combustion with alka/enes

A

Carbon Dioxide and Water

49
Q

Ethene into a polymer equations

A

Ethene -> Poly(ethene)
Pressure and Catalyst
C2H4 -> (C2H4)n

50
Q

What are nanoparticles

A

Really tiny particles, 1-100 nanometres across
they have different properties from the bulk chemical its made from - fullerenes are different from lumps of carbon

51
Q

How many atoms do nanoparticles roughly have?

A

a few hundred atoms, so bigger than atoms and simple molecules but smaller than pretty much everything else

52
Q

What is an example of nanoparticles?

A

Fullerenes - they contain nanotubes
the covalent bonds make it carbon nanotubes very strong

53
Q

Why do nanoparticles have a high surface area to volume ratio?

A

As particles decease in size, the size of their surface area increases in relation to their volume
so SA:V ratio increases

54
Q

How does a nanoparticles high SA:V ratio affect them?

A

High SA:V ratio compared to bigger particles
-> Gives them different properties, because a much greater proportion of their atoms are avaliable to interact with substances they come into contact with.

55
Q

What is nanoscience

A

Usng nanoparticles

56
Q

What new uses of Nanoparticles being developed?

A

Catalysts
Cosmetics
Nanomedicine
Lubricant coatings
Electic chips
Sports equipment
Surgical masks and wound dressings

57
Q

How are Nanoparticles being used as catalysts?

A

Huge SA:V ratio, so they can make good catalsysts
SA increase = FreQ Collisions increase = increase RofR

58
Q

How are Nanoparticles being used for new cosmetics?

A

New cosmetics e.g. sunscreens, have been made using nanoparticles.
The small particles provide better protection but dont leave white marks on skin

59
Q

How are Nanoparticles being used as Nanomedicine?

A

The idea for nanomedicine is that tiny fullerenes are absorbed more easily by the body than most particles. This means they could deliver drugs right into the cells where its needed.

60
Q

How are Nanoparticles being used as lubricant coatings?

A

New lubricants using fullerenes e.g. artificial joints and gears

61
Q

How are Nanoparticles being used in electricals?

A

Nanoparticles conduct electricity, so they can be used in tiny electric circuits for computer chips

62
Q

How are Nanoparticles being used for sports equipment?

A

Nanoplastics are added to plastics in sports equipment. e.g. tennies rackets, golf clubs and golf balls.
They make plastic much stronger and more durable, without adding much mass

63
Q

How are Nanoparticles being used in medical equipment?

A

Silver nanoparticles are added to the polymer fibres to make surgical masks and wound bandages. This gives the fibres antibacterial properties

64
Q

How are the the effects of nanoparticles on health not fully understood?

A
  • the way they effect the body isnt undestood - important new products are fully tested
  • Some are worried we are using nanoparticles before the effects on human bodys are fully discovered
  • e.g. they may not be able o break down properly, causing a build up in cells.

Chemistry (8 decks)

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