Organic Chemistry Flashcards

1
Q

Examples of fossil fuels (3)

A

Petroleum (Crude oil)

Natural gas (mainly methane)

Coal

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2
Q

How is crude oil formed (2)

A

formed from remains of animals/plants pressed together under layers of rock

found underground + trapped between layers of impermeable rock

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3
Q

Where is Natural Gas found

A

trapped in pockets above crude oil

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4
Q

Features of fossil fuels (2)

A

non-renewable

valuable resource

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5
Q

Fractional Distillation in Petroleum/crude oil (4)

A

crude oil heated in furnace

passed into bottom of fractioning column

gives off mixture of vapours that rise up column

different fractions condense at different heights

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6
Q

Fractions at top of column (2)

A

light coloured liquid

runny liquid

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7
Q

Fractions at bottom of column (3)

A

dark

sticky

viscous - thick liquids that are not runny

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8
Q

Define hydrocarbon molecules (2)

A

molecules which contain only hydrogen and carbon

chemically bonded with covalent bonds but have different carbon atoms

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9
Q

Why is petroleum able to seperate

A

have different boiling points

longer hydrocarbon molecule = stronger intermolecular forces –> greater boiling point

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10
Q

Define petroleum

A

mixture of hydrocarbon molecules

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10
Q

Define volatile in terms of hydrocarbons

A

from vapour more easily

describes smaller molecule hydrocarbons

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11
Q

Shorter hydrocarbons burning features (3)

A

small flame

ignite easily

blue flame + almost no smoke

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12
Q

Longer hydrocarbon burning features (3)

A

large flame

difficult to light

yellow/smoky(grey) flame

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13
Q

Which hydrocarbon molecules are more useful? smaller ones or longer ones?

A

smaller

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14
Q

Catalytic cracking (2)

A

process to break down large hydrocarbon molecules into smaller ones

requires high temperatures between 600-700 degrees C + catalyst of silica or alumina

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15
Q

Features of homologous series (4)

A

have similar chemical properties

have same general formula

show gradual change in physical properties (e.g melting/boiling point)

differ from previous member of series by CH2

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16
Q

Define alkanes (4)

A

homologous series of organic molecules

hydrocarbons

made up of carbon atoms linked by a single covalent bond

known as saturated hydrocarbons

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17
Q

Where are alkanes obtained from

A

crude oil by fractional distillation

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18
Q

Smallest Alkenes (2)

A

used as fuels

relatively unreactive

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19
Q

Methane Alkane features (4)

A

CH4

  H 
  | H - C - H
  |
  H

boiling point of -162 degrees C

gas at room temperature/pressure

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20
Q

Ethane Alkane Features (4)

A

C2H6

 H     H
  |    | H - C - C - H
  |    |
  H   H

boiling point of -89 degrees C

gas at room temperature/pressure

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21
Q

Butane Alkane Features (4)

A

C4H10

  H  H   H    H
  |   |    |    | H - C - C - C - C - H
  |    |   |    |  
  H   H   H   H

boiling point of 0 degrees celsius

gas at room temperature/pressure

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22
Q

Propane Alkane features (4)

A

C3H8

  H  H   H   
  |   |    |    H - C - C - C  - H
  |    |   |   
  H   H   H   

boiling point of -42 degrees C

gas at room temperature/pressure

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23
Q

Properties of alkanes (5)

A

CnH2n+2

saturated (no double C=C bond)

burn in oxygen to form CO2 + H2O (CO if limited supply of oxygen)

low reactivity - strong c-h bonds require lots of energy + hard to break

used as fuel

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24
Q

Alkane combustion in plentiful supply of air/oxygen (complete combustion) (3)

A

burn to form carbon dioxide + water

blue flame produced

alkane + 2O2 –> CO2 + 2H2O

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25
Q

Alkane combustion in limited supply of air/oxygen (incomplete combustion) (3)

A

forms carbon + water

yellow flame produced

alkane + O2 –> C + 2H2O

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26
Q

Alkane other incomplete combustion (2)

A

forms carbon monoxide + water (dangerous)

alkane + 3O2 –> 2CO + 4H2O

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27
Q

Carbon monoxide features (2)

A

no colour

no smell

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28
Q

Safety precautions for carbon monoxide (4)

A

service heaters or boilers regularly

ensure that jets aren’t blocked + limit air supply

ensure that exhaust flues aren’t blocked + allow carbon monoxide into room

flame should always be blue

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29
Q

Define alkenes (5)

A

homologous series

formed by catalytic cracking

unsaturated hydrocarbons - contain at least one carbon to carbon double bonds

burn well

reactive - due to carbon-to-carbon double bond

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30
Q

Ethene Alkene features (3)

A

C2H4

H H
\ /
C=C
/ \
H H

boiling point of -104 degrees C

gas at room temperature/pressure

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31
Q

Propene Alkene features (4)

A

C3H6

H H H H
\ / | /
H - C H or H - C - C=C
\ / | | \
C=C H H H
/ \
H H

boiling point of propene -48 degrees celsius

gas at room temperature/pressure

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32
Q

Butene Alkene Features (4)

A

C4H8

  H  H   H      H
  |   |   |      / H - C - C - C=C 
  |    |   |     \
  H   H  H     H

boiling point of -6 degrees C

gas at room temperature/pressure

33
Q

Test to distinguish alkenes from alkanes/unsaturated hydrocarbon from saturated hydrocarbon (3)

A

adding bromine water

alkanes - do not react with bromine water so colour does not change

alkene - reacts with bromine so it loses colour (colourless)

34
Q

Addition reaction (hydrocarbon reaction with bromine water) with ethene and bromine equation (2)

A

Ethene (g) + Bromine (aq) –> 1,2-dibromoethane (l)

H H H H
\ / | |
C=C + Br-Br –> H - C - C - H
/ \ | |
H H Br Br

35
Q

Addition reaction (hydrocarbon reaction with bromine water) with ethene and bromine explanation (2)

A

bromine molecule (Br2) splits

2 bromine atoms add to carbon atoms on either side of double bond

36
Q

How polymers of ethene form (2)

A

ethene monomers react with other ethene monomers

form polymer called polyethene

37
Q

Ethene reaction with hydrogen (2)

A

forms ethane

H H H H
\ / | |
C=C + H-H –> H - C - C - H
/ \ | |
H H H H

38
Q

Ethene reaction with steam (2)

A

300 C, 70 atm
Ethene + Steam –> ethanol
phosphoric acid catalyst

H H H H
\ / | |
C=C + H2O –> H - C - C - OH
/ \ | |
H H H H

39
Q

Properties of alkenes (6)

A

CnH2n

unsaturated - contains double C=C bond

burns in oxygen to form H2O + CO2 (CO if limited supply of oxygen)

high reactivity - due to double C=C bonds

test - turn bromine water from orange to colourless

used to make polymers

40
Q

Define alcohols (2)

A

molecules containing the OH functional group

CnH2n+1OH

41
Q

Methanol Alcohol Features (3)

A

CH3OH

  H 
  | H - C - OH
  |
  H

boiling point of 65 C

42
Q

Ethanol Alcohol Features (3)

A

C2H5OH

 H     H
  |    | H - C - C - OH
  |    |
  H   H

boiling point of 78 C

43
Q

Ethanol combustion reaction in air (2)

A

Ethanol + Oxygen –> carbon dioxide + water

C2H5OH (l) + 3O2 (g) –> 2CO2 (g) + 3H2O (l)

44
Q

Define isomer

A

compounds with same molecular formula but different structural formula

45
Q

Isomers in alkenes (2)

A

position of double carbon bond changing

e.g but-1-ene

46
Q

3 things a fire needs (3)

A

fuel

oxygen

heat

47
Q

Define saturated in terms of hydrocarbons (2)

A

all carbon to carbon bonds are single bonds

e.g alkanes

48
Q

Define unsaturated in terms of hydrocarbons (2)

A

all carbon to carbon bonds are double or triple bonds

e.g alkenes

49
Q

Why does Bromine decolourise an unsaturated hydrocarbon but does not decolourise a saturated hydrocarbon (2)

A

carbon to carbon double bond breaks in unsaturated hydrocarbon

allows for 2 Br atoms to be added to each carbon

50
Q

Define halogenation reaction in terms of alkenes

A

reaction between alkenes and a halogen

51
Q

Define hydrogenation reaction in terms of alkenes (3)

A

reaction between alkene and hydrogen

alkene becomes alkane

temperature of 200 degrees celsius + nickel catalyst required

52
Q

Use of hydrogenation (4)

A

produce margarine from unsaturated oils

unsaturated oils contain carbon to carbon double bonds

hydrogen causes oils to become more saturated

raises melting point of oil –> becomes solid margarine

53
Q

Define hydration reaction in terms of alkenes (4)

A

reaction between steam (water) and an alkene

produces an alcohol

requires temperature of 300 degrees C + phosphoric acid as a catalyst

H2O splits into H + OH –> H adds to one carbon, OH adds to other carbon

54
Q

More short chain hydrocarbons are produced than long chain hydrocarbons when crude oil undergoes fractional distillation

True or False?

A

False

55
Q

Which hydrocarbon is more widely used in the world? Small chain or Large chain?

A

Small chain

56
Q

Define cracking in terms of hydrocarbons (3)

A

long chain hydrocarbons are broken into smaller ones

produces mixture of alkanes and alkenes produced

2 types of cracking : thermal cracking + Catalytic cracking

57
Q

Define thermal cracking (3)

A

cracking long chain alkanes to smaller ones

high temperature required (800 degrees C)

ethene + hydrogen gas produced

58
Q

Advantages and Disadvantages of thermal cracking (2)

A

ad - more useful for cracking longer chain alkanes

dis - expensive due to high temp. required

59
Q

Define Catalytic Cracking (2)

A

uses aluminum + ceramic based catalysts

catalysts lower required temp. to 500 C

60
Q

Advantages and Disadvantages of Catalytic Cracking (2)

A

Ad - cheaper

Dis - not as effective in cracking longer hydrocarbons into smaller ones

61
Q

Name two main methods to produce ethanol (2)

A

Fermentation

Catalytic addition of steam to ethene

62
Q

Where does fermentation for ethanol production take place

A

closed system in large vats

63
Q

Define fermentation process for ethanol production (3)

A

glucose broken down by yeast producing carbon dioxide + ethanol

yeast acts as catalyst

must occur in absence of oxygen + temp of 37 C (too high = catalyst destroyed)

64
Q

Anaerobic respiration formula

A

C6H12O6 –> 2C2H5OH + 2CO2

65
Q

Explain the process of hydration of ethene for ethanol production (2)

A

alkene reaction with steam produces alcohol

requires temp. of around 550 C + strong acid catalyst (e.g sulfuric or phosphoric)

66
Q

Uses of Ethanol (5)

A

alcoholic drinks

solvents - OH group allows it to dissolve in water

perfume - evaporate easily so leaves solute behind on product applied + safe on human skin

cleaning products - dissolve variety of compounds + evaporate easily

fuel - highly flammable + burns with clean flame

67
Q

Use of methanol

A

fuel in racing cars

68
Q

Define a polymer (2)

A

long chain molecules formed from monomers

can be natural or synthetic

69
Q

Naturally occuring polymers (4)

A

wool

cotton

protein

carbohydrates

70
Q

Synthetic polymers (3)

A

nylon

kevlar

polythene

71
Q

Define polymerisation

A

reaction in which monomers join to form polymers

72
Q

Define monomer

A

small + single unit of substance that joins together to form polymer

73
Q

How you name a polymer

A

adding poly to name of monomer enclosed in brackets

74
Q

Define addition polymerisation

A

polymerisation of individual alkenes

75
Q

How does addition polymerisation work (2)

A

carbon to carbon double bond is broken - creates single bond between carbon atoms + bond to other atoms

allows other monomers to join with carbon atom

76
Q

Displaying monomers in addition polymerisation (3)

A

should be written in H shape

then surrounded by brackets

repeating unit (n) in bottom right corner

77
Q

Define repeating unit

A

shows a section of a polymer which is repeated

78
Q

Define condensation polymerisation (2)

A

made from 2 different monomers

joins through condensation reaction - 2 molecules joining together expend a smaller molecule

79
Q

How nylon polymer forms (3)

A

made up of dichloride monomer + diamine monomer

cl from dichloride joins with h from diamine –> forms HCl

C from dichloride can join with N from diamine –> creates polymer

80
Q

How to identify whether the polymer was made from addition polymerisation or condensation polymerisation

A

condensation polymerisation = main chain has elements other than carbon