Organics Flashcards

1
Q

what is a hydrocarbon

A

a compound made up of only hydrogen and carbon

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2
Q

write the general equation for the complete combustion of an alkane/hydrocarbon

A

hydrocarbon + o2 -> CO2 + H2O

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3
Q

write the general equation for the incomplete combustion of an alkane/hydrocarbon

A

hydrocarbon + o2 -> CO + H2O (+soot)

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4
Q

Molecular formula of methane

A

CH4

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5
Q

Molecular formula of Ethane

A

C2H6

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6
Q

Molecular formula of propane

A

C3H8

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7
Q

Molecular formula of butane

A

C4H10

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8
Q

Molecular formula of pentane

A

C5H12

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9
Q

how to draw the molecular, general, structural and displayed formulae of Ethane

A

molecular: C2H6
general: CnH2n+2
structural: CH3CH3
displayed: H H
H - C - C - H
H H

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10
Q

what is a homologous series

A

a group of organic molecules which share common characteristics

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11
Q

what is a functional group

A

a group of atoms responsible for the chemical properties of a compound

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12
Q

what is an isomer

A

molecules with the same molecular formula but with a different arrangement of atoms in space

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13
Q

how to know if a molecular formula is a carboxylic acid and how would you name an organic compound because of it

A

-COOH

-oic acid

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14
Q

What are the four steps to naming organic compounds
UNFINISHED

A

1) count the number of carbon atoms in the carbon chain - this gives you the stem
(1=meth 2=eth 3=prop 4=but 5=pent 6=hex)

2) find the main functional group:
alkane(only single bonds) = -ane
alkene(contain a C=C) = -ene
alcohol(contain -OH) = -ol

3) number the carbon chain so that the functional group has the lowest possible number

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15
Q

how to know if a molecular formula is an alcohol and what suffix would you use when naming it

A

-OH
-ol
(ethanol)

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16
Q

what is crude oil

A

a mixture of different length hydrocarbons

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17
Q

what would this organic molecule be called and why

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

2,2-dimethly butane

di - how many methyl molecules are attached

2,2 the positions of the methyl molecules

butane - 4 carbons in the longest chain

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18
Q

are alkanes saturated or unsaturated and why

A

saturated - they only have single bonds

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19
Q

Describe the four steps of fractional distillation

A

1) oil is heated then pumped into the tower where it vaporises
2) The column is very hot at the bottom but cooler at the top so as the vaporised oil rises, they reach their boiling point so they cool and condense
3) Heavy fractions (containing large molecules) have a high boiling point so condense near the bottom
4) lighter fractions (containing small molecules) have a lower boiling point and condense further up the column

similar vapours condense together to form a fraction

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20
Q

names of the main fractions obtained from crude oil from lightest to heaviest

A

refinery gases (liquid petroleum gas)
gasoline
kerosene (Naphtha then Paraffin)
diesel
fuel oil
bitumen

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21
Q

what are refinery gases used for

A

bottled gas

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22
Q

what is gasoline used for

A

fuel for cars

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23
Q

what is kerosene used for

A

aircraft fuel

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24
Q

what is diesel used for

A

fuel for lorries and buses

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25
Q

what is fuel oil used for

A

fuel ships, and power stations

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26
Q

what is bitumen used for

A

roads, rooves

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27
Q

what is the trend in colour of the different crude oil fractions

A

get darker in colour as you go down the column

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28
Q

what is the trend in boiling point of the different crude oil fractions

A

boiling point increases as you go down the column

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29
Q

what is the trend in viscosity of the different crude oil fractions

A

viscosity increases as you go down the column

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30
Q

what is fuel

A

a substance that, when burned, releases heat energy

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31
Q

why is carbon monoxide bad for a person

A

Carbon monoxide is a toxic gas. It is absorbed in the lungs and binds with the haemoglobin in the red blood cells to form carboxyhaemoglobin. This reduces the capacity of the blood to carry oxygen as it binds so strongly that it keeps oxygen from binding as well.

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32
Q

know that, in car engines, the temperature reached is high enough to allow nitrogen and oxygen from air to react, forming oxides of nitrogen.

explain how the combustion of some impurities in hydrocarbon fuels results in the formation of sulfur dioxide.
understand how sulfur dioxide and oxides of nitrogen oxides contribute to acid rain.

A

.

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33
Q

what is the general formula for alkanes

A

CnH2n+2

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34
Q

and to name the unbranched-chain isomers.

A

.

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35
Q

what is the trend in molecular mass of the fractions as boiling point increases

A

as boiling point increases, molecular mass gets higher

36
Q

what are fractions (from fractional distillation)

A

mixtures containing the hydrocarbons that boil in a particular temperature range

eg kerosene contains all the hydrocarbons that boil between 250C and 350C

37
Q

what are alkanes

A

hydrocarbons that fit the general formula CnH2n+2

38
Q

what is the displayed formula for C4H10

A
39
Q

what does the structural formula of C4H10 look like

A
40
Q

what is the molecular formula of butane

A
41
Q

what is the empirical formula of C4H10

A

C2H5

42
Q

what are the five homologous series

A

alkanes
alkenes
alcohols
carboxlic acids
esters

43
Q

what is a homologous series

A

a group of organic molecules which share common characteristics

44
Q

what five characteristics does a homologous series share

A
  • a trend in physical properties
  • similar chemical properties
  • same functional group
  • same general formula
  • neighboring members of the series differ by CH2
45
Q

what is an isomer

A

molecules with the same molecular formula with a different structural formula

46
Q

why are alkanes used as fuels

A

they release a lot of energy when combusted

47
Q

what are the two types of combustion that alkanes can undergo

A

complete
incomplete

48
Q

chemical word equation of the complete combustion of an alkane

A

alkane + oxygen -> carbon dioxide + water

49
Q

chemical word equation of the incomplete combustion of an alkane

A

alkane + oxygen -> carbon monoxide + water + C (soot)

50
Q

why does incomplete combustion happen

A

due to a shortage of oxygen

51
Q

why do alkanes become less useful as a fuel when there is low oxygen

A

because incomplete combustion occurs which means it releases less energy

52
Q

what three pollutants does the combustion of fuels release

A
  • carbon monoxide
  • nitrogen oxides
  • sulfur dioxide
53
Q

how are nitrogen oxides formed during the combustion of alkanes (dangers of using alkanes as fuels)

A

because the nitrogen in the air gets very very hot from the car engine so they have enough energy to combust, forming the nitrogen oxide

these then dissolve in water to form acid rain which is harmful to nature and aquatic life

54
Q

how are sulfur dioxides produced when alkanes are burned

A

when sulfur impurities in the fuel combust

it can dissolve in rainwater to form acid rain

55
Q

how do alkanes react with halogens

A

by swapping out on hydrogen atom for one halogen atom

56
Q

what two details about alkanes reacting with halogens are important to know

A
  • it is a substitution reaction (because the H swaps with the Br)
  • the reaction requires UV light (because the alkane is pretty unreactive)
57
Q

what is the purpose of cracking

A
  • crude oil tends to contain much more longer alkanes than shorter ones, unfortunately the shorter ones are much more useful
  • to get around this we take the longer alkanes and do CRACKNIG
58
Q

what is cracking

A

breaking down longer alkanes into smaller, more useful ones

59
Q

what conditions does cracking need to occur

A

temperature: 650*C
catalyst: aluminium oxide

it can be done without a catalyst but far more energy would need to be provided

60
Q

word equation for cracking

A

long alkane -> shorter alkane + alkene
(any combination is possible as long as the numbers of C and H atoms adds up)

eg

61
Q

what is an alkene

A

hydrocarbons that fit the general formula CnH2n

62
Q

how do alkanes differ from alkenes

A

alkanes are saturated, alkenes are unsaturated because they have a C=C bond

63
Q

how is the structural formula of an alkene formed

A
64
Q

in what two ways can the isomers of alkenes differ

A
65
Q

how does the combustion of alkenes differ from that of alkanes

A

it doesn’t

they can both completely combust or incompletely combust in the same way with the same products

66
Q

how do alkenes react with bromine

A
67
Q

what are the four details you need to know about alkenes reacting with bromine

A
  • it is an addition reaction (because you are adding the bromine atoms into the alkene)
  • the reaction happens without UV light (because alkenes are more reactive than alkanes)
  • it works with pure bromine liquid or bromine water
  • the mixture turns from orange to colourless (because the bromine is used up in the reaction)
68
Q

how to test if a mystery hydrocarbon is an alkane or an alkene

A
69
Q

when do addition polymers form

A

when molecules with a C=C bond add into chains. they lose their double bond to form single bonds with the next molecule

70
Q

what is a monomer (that bonds together to form an addition polymer)

A

small molecules that can be bonded to other identical molecules to form a polymer

71
Q

what does the n represent

A

the number of repeats of this unit in the polymer chain

72
Q

how to form the name of the polymer created by (eg) ethene

A

by putting poly in front of the monomer name
poly(ethene)

73
Q

what are the four most commonly encountered polymers

A
  • poly(ethene)
  • poly(propene)
  • poly(chloroethene)
  • poly(tetrafluoroethene)
74
Q

what are two uses of poly(ethene)

A
  • drinks bottles
  • shopping bags
75
Q

what are two uses of poly(propene)

A
  • storage boxes
  • climbing ropes
76
Q

what are two uses of poly(chloroethene)

A
  • wire insulation
  • drainpipes
77
Q

what is the use of poly(tetrafluorethene)

A

non-stick coating

78
Q

what does inert mean

A

very unreactive

79
Q

why don’t addition polymers break down easily

A

they are inert, which means they are very chemically unreactive

80
Q

what three ways can you dispose of unwanted addition polymers

A
  • reuse it
  • recycle it
  • incinerate it (and use the energy to generate electricity)
81
Q

what is a fuel

A

a substance that when burned, releases heat energy

82
Q

what are the three main bad gases that are made when burning hydrocarbons

A
  • carbon monoxide
  • sulfur dioxide
  • nitrogen oxides
83
Q

why are nitrous oxides produced when burning hydrocarbons

A

in car engines the temperarure reaches a high enough heat to allow nitrogen and oxygen to react (combustion) and form nitrous oxides

84
Q

why is sulfur dioxide formed when combusting hydrocarbons

A

WHEN THE IMPURITIES COMBUST

85
Q

are alkanes saturated or unsaturated and why

A

saturated - only single c-c bonds present

86
Q

what is the functional group of alkanes

A

c=c

87
Q

general formula for the reaction between an alkene and bromine

A

alkene + bromine -> dibromoalkane