Paper 2 - Topic 7, Organic Chemistry Flashcards

1
Q

What is addition polymerisation

A

A reaction where many small molecules (monomers) join together to form very large molecules to form (polymers)

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2
Q

What are alcohols

A
  • contain the functional group -OH
  • the first four members of the homologous series of alcohols are methanol, ethanol, propanol and butanol
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3
Q

What are alkanes

A

Alkanes are the most common hydrocarbon found in crude oil

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4
Q

What is the general formula for alkanes

A

CnH2n+2

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5
Q

What are alkenes

A

Alkenes are hydrocarbons with a double carbon bond between two of the carbon atoms in their chain, causing them to be unsaturated

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6
Q

What is the general formula for alkenes

A

CnH2n

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7
Q

What are carboxylic acids

A
  • Carboxylic acids have the functional group -COOH
  • the first four members of a homologous series of carboxylic acids are methanoic acid, ethanoic acid, propanoic acid and butanoic acid
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8
Q

What is catalytic cracking

A

Long-chain hydrocarbons are heated to turn them into a gas. The vapour is then passed over a hot powered aluminium oxide catalyst. The long chain molecules spilt apart on the surface of the catalyst

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9
Q

What is combustion

A
  • combustion of hydrocarbon fuels releases energy
  • during combustion, the carbon the carbon and hydrogen in the fuels are oxidised
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10
Q

What is complete combustion in a hydrocarbon

A

Water and carbon dioxide are the only products of the complete combustion of a hydrocarbon

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11
Q

What is crude oil

A
  • A finite resource found in rocks
  • remains of ancient biomass and consists mainly of plankton that was buried in mud
  • most of the compounds in crude oil are hydrocarbons
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12
Q

What is condensation polymerisation

A
  • reactions involve monomers with two functional groups
  • when these monomers react they join together and lose small molecules such as water
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13
Q

What is cracking

A

A process that involves breaking down larger hydrocarbons to produce smaller more useful molecules, cracking can be done by catalytic cracking or steam cracking

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14
Q

What are esters

A

The product of a condensation reaction between a carboxylic acid and alcohol
Eg ethanol + ethanoic acid —> ethyl ehanoate

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15
Q

What is fermentation

A

A chemical process by which molecules such as glucose are broken down anaerobically, ethanol is produced when sugar solutions are fermented using yeast

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16
Q

What is fractional distillation

A

A method of separating a mixture of substances according to their different boiling points, commonly used to separate crude oil into different fractions

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17
Q

What is a homologous series

A

A series of compounds with the same functional group and similar chemical properties

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18
Q

What are hydrocarbons

A

Molecules that are made up of hydrogen and carbon atoms only

19
Q

What are polyesters

A

A category of polymers which contain the ester functional group in the main chain, formed from condensation polymerisation

20
Q

What are polymers

A

Large long-chain molecules made up of lots of small monomers joined together by covalent bonds

21
Q

What is steam cracking

A
  • Long-chain hydrocarbons are heated to turn them into a gas
  • the hydrocarbon vapour is then mixed with steam and heated to a very high temperature which caused them to spilt into smaller molecules
22
Q

What is a mixture

A
  • 2 or more elements that are not chemically combined
23
Q

How does fractional distillation work for separating different parts of oil

A
  • oil is heated in the fractionating column and the oil evaporates and condenses at a different number of temperatures
  • the fractionating column works continuously
  • heated crude oil is piped in the bottom, the vapour is Ed oil evaporates and rises up the column and the various fractions are constantly tapped off at the different levels where they condense
24
Q

What are the properties of shorter hydrocarbons

A
  • less viscous (more runny)
  • the shorter the molecule, the lower the temperature at which that fraction is vaporised or condensed and the lower the boiling point
  • more flammable
25
Q

What are the properties of longer hydrocarbons

A
  • more viscous (less runny)
  • higher boiling point (higher temperature for the fraction to be vaporised or condensed)
  • less flammable
26
Q

What is the equation for hydrocarbons

A

Hydrogen —> carbon dioxide + water

27
Q

Why are hydrocarbons burnt

A

So they can be used as fuel as the reaction produces energy

28
Q

What are the processes of cracking

A
  • passing them over a hot catalyst
  • OR mixing them with steam and heated to a very high temp so that thermal decomposition reactions occur
29
Q

What happens when you react and you react an alkene with bromine water

A

Turns it from orange to colourless

30
Q

How can cracking be useful

A

Products made will have shorter chains that the alkanes you started with, making them more flammable and a better fuel

31
Q

What happens when you burn alkenes

A

They burn with smoky flames due to incomplete combustion

32
Q

What happens when an alkene is reacted with hydrogen, water and halogens

A
  • the double carbon bond is broken to a singular carbon bond
  • the compound added splits into two groups and the two groups and added to the 2 different carbons in the C=C bond
  • H2 spilts into two H’s
  • H2O splits into a H and OH
  • Br 2 splits into two Br’s
33
Q

What is the molecular formula for methanol

A

CH3OH

34
Q

What is the molecular formula for ethanol

A

C2H5OH

35
Q

What is the molecular formula for propanol

A

C3H7OH

36
Q

What is the molecular formula for butanol

A

C4H9OH

37
Q

What are the reactions of the alcohols

A
  • they burn in air, which produces carbon dioxide and water
  • they dissolve in water to form a neutral solution
  • they react with sodium to produce hydrogen and a salt
  • they react with oxidising agents to form carboxylic acids
38
Q

What are the uses of methanol

A
  • chemical feedstock, in anti-freeze, to make biodiesel
39
Q

What are the uses of ethanol

A
  • main use is alcoholic drinks
  • also used as a solvent and fuel
40
Q

How can you produce ethanol

A
  • the fermentation of sugar with yeast using renewable sources
  • conditions : about 35 degrees C, anaerobic and yeast enzyme catalyst
  • sugar —> ethanol + carbon dioxide
41
Q

What are the reactions of the carboxylic acids

A
  • they dissolve in water to produce acidic solutions (pH is less than 7)
  • they react with metal carbonates to produce carbon dioxide, a salt and water
  • react with alchols in the presence of an acid catalyst to produce esters
42
Q

What happens when carboxylic acids react with alcohols to produces esters

A
  • they don’t completely ionise in solutions (don’t release many H+ ions) making carboxylic acids weak acids
  • they have a higher pH (less acidic) than solutions of strong acids of the same concentration
43
Q

When drawing a polymer, what do you need to remeber

A
  • no double carbon bond
  • draw the bonds coming off of the C’s (out of the brackets)
  • write a little ‘n’ outside of bracket