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gcse science > Science - Chemistry - Organic Chemistry - C7 > Flashcards

Science - Chemistry - Organic Chemistry - C7 Flashcards

1
Q

what is organic chemistry ?

A

the study of substances which contain carbon atoms

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2
Q

what is a hydrocarbon ?

A

A hydrocarbon is any molecule which contains hydrogen and carbon atoms only

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3
Q

give an example of a hydrocarbon

A

C10H22 - decane (an alkane)

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4
Q

what are alkanes ?

A

madeup of chains of 1 carbon for every 4 hydrogen

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5
Q

are there double carbon bonds in alkanes ?

A

no

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6
Q

how are carbon bonds saturated ?

A

all atoms from bonds with as many other atoms as they can

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7
Q

list first for alkanes

A

methane
ethane
propane
butane

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8
Q

what is the general formula for alkenes

A

CnH2n+2

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9
Q

give 3 properties of hydrocarbons :

A
  • the shorter the molecule, the less viscous it is
  • the shorter the molecule - the lower the boiling point is
  • the shorter the molecule - the more flammable it is
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10
Q

how does combustion with hydrocarbons work ?

A

carbon and hydrogen react with oxygen to form carbon dioxide and water vapour, energy is also released

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11
Q

what is complete combustion in hydrocarbons ?

A

carbon atoms are fully oxidised

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12
Q

what is the equation for complete combustion ?

A

hydrocarbon + oxygen - carbon dioxide + water vapour

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13
Q

what is crude oil ?

A

a fossil fuel made up of a different of different compounds, formed of plants and animals, mainly plankton - which dies millions of years ago and were buried in mud. Over millions of years and high temperatures crude oil was formed

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14
Q

how do we get crude oil ?

A

drilling it up from underground

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15
Q

is crude oil renewable ?

A

no

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16
Q

what is crude oil made up of- be specific ?

A

hydrocarbons, mainly alkanes

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17
Q

how is fractional distillations used to split up different hydrocarbons in crude oil ?

A
  • crude oil is pumped into a fractionating column
  • crude oil evaporates
  • crude oil is pumped into the bottom of the column
  • the column is hottest at the bottom, cooler at the top
  • gas rises up the column and gradually cools
  • different compounds have different boiling points so they condense at different temperatures
  • hydrocarbons that similar number of carbon atoms condense in similar levels
  • the group of hydrocarbons that condense together are called fractions
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18
Q

give example of hydrocarbons which cool near the bottom of the column

A
  • bitumen
  • heavy fuel oil
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19
Q

give examples of hydrocarbons which cool near the middle

A
  • kerosene
  • ## diesel oil
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20
Q

give examples of hydrocarbons which cool near the top of the column

A
  • LPG
  • petrol
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21
Q

what is crude oil used for ?

A

fueling cars, planes, trains

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22
Q

what does LPG help do ?

A

is stored in high pressure in a bottle as a gas, when tap on bottle is open fuel vaporises and flows to burner where its ignited

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23
Q

what does petrol help to do ?

A

liquid, so is stored in fuel tanks and can flow to the engine where its mixed with air before ignited

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24
Q

how does viscous hydrocarbons help ?

A

they are gloopy, so help lubricate engine parts and cover roads

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25
Q

what is feedstock, and how are they used

A

petrochemical industry use hydrocarbons as feedstock, and make new compounds for things like polymers, solvents, lubricants and detergents

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26
Q

what are organic compounds ?

A

compounds containing carbon atoms

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27
Q

are all products from crude oil organic compounds ?

A

yes

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28
Q

what is a homologous series ?

A

groups of carbon atoms products which bond together

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29
Q

give examples of homologous series

A

alkanes
alkenes
alcohols
carboxylic acids

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30
Q

do compounds in the same homologous series share similar properties ?

A

yes

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31
Q

what is cracking ?

A

splitting long chain hydrocarbons into shorter ones

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32
Q

why do we use cracking ?

A

long chain hydrocarbons are less useful, as they are more gloopy form things like tar

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33
Q

what is good about short chain hydrocarbons ?

A

they are flammable, good for fuels

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34
Q

what else can be produced from cracking ?

A

substances like ethene, which is useful for plastics

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35
Q

how does cracking work ?

A

thermal decomposition

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36
Q

what is thermal decomposition ?

A

breaking molecules down by heating them

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37
Q

what are the 2 types of thermal decomposition used in cracking ?

A

catalytic cracking
steam cracking

38
Q

describe catalytic cracking

A

heat long chain hydrocarbon to vaporise it
vapour is passed over a hot, powdered catalyst, e.g aluminium oxide
long chain molecule cracks

39
Q

describe steam cracking

A
  • heat long chain hydrocarbon to vapourise it
    vapor is mixed with steam
    heated at a very high temperature
    cracking
40
Q

what are most of the products of cracking ?

A

alkanes and alkenes

41
Q

what are alkenes ?

A

a homologous series which are more reactive than alkanes with a double double carbon bond

42
Q

why are alkenes unsaturated ?

A

they have fewer hydrogen atoms than the alkane with the same number of carbons

43
Q

what is the formula of an alkene ?

A

CnH2n - x2 hydrogen’s to carbons

44
Q

why is the alkenes being reactive useful ?

A

they are good for starting materials to make other compounds

45
Q

give an example of how alkenes are reactive ?

A

it turns orange bromine water colourless

46
Q

what are the first 4 alkenes ?

A

ethene
propene
butene
pentene

47
Q

what happens when there’s not enough oxygen and alkenes are burnt ?

A

incomplete combustion

48
Q

what happens during incomplete combustion of alkenes ?

A

a smoky yellow flame and less energy is released

49
Q

what is the equation of incomplete combustion in alkenes ?

A

alkene + oxygen - carbon + carbon monoxide + carbon dioxide + water

50
Q

what is the alkenes functional group ?

A

C=C double bond

51
Q

what is a functional group ?

A

a group of atoms which determines how a compound typically reacts

52
Q

how do alkenes react via addition reactions ?

A

the c=c double bond opens up to leave a single bond and a new atom is added to each carbon

53
Q

what is the hydrogenation of alkenes ?

A

it forms an alkane when hydrogen is added

54
Q

how do alkenes and alcohols react ?

A

with steam, water is added

55
Q

what reacts with alkenes when reacting with an alcohol (displayed formula)

56
Q

what is addition polymerisation ?

A

lots of small alkene molecules (monomers) open up their double bonds to form long chain molecules called polymers, products have the same number of atoms and the same type of atoms as the monomers

57
Q

what does the addition polymerisation reaction require ?

A

high pressure and a catalyst

58
Q

what are alcohols ?

A

a group of homologous series with an OH- functional group

59
Q

what is the formula of alcohols ?

60
Q

what is the first alcohol ?

61
Q

what are the properties of alcohols ?

A
  • flammable
  • dissolves in water to form neutral solutions
  • react with sodium
  • they can be oxidised by reacting with oxygen to form carboxylic acid
62
Q

how are alcohols used ?

A

drinks (ethanol)
solvents (methanol, ethanol, propanol, butanol) ethanol is used for perfumes
fuels - ethanol burns cleanly and isn’t smelly - mixed with petrol as fuel for cars

63
Q

how is ethanol made from sugars ?

A

fermentation

64
Q

what is the fermentation equation ?

A

sugar - yeast - carbon dioxide + ethanol

65
Q

what is made by fermentation ?

A

beer, wine

66
Q

what is the raw material for fermentation ?

67
Q

what conditions does fermentation happen in ?

A
  • a solution so ethanol is made aqueous
  • at 37 degrees in acidic, anaerobic conditions, this is because the enzymes work best at this temperature
68
Q

what are carboxylic acids ?

A

compounds in a group of -COOH consisting of a carbon atom that has formed a double bond with an oxygen atom and a single bond with an oxygen atom in the OH- group

69
Q

what are the properties of carboxylic acids ?

A
  • reacts like other acids
  • dissolves in water to ionise and release H+ ions
  • partially ionises in water and are weak acids
70
Q

what does carboxylic acids being weak acids mean ?

A

they have a higher PH than aqueous solutions of strong acids

71
Q

what are esters ?

A

a functional group of -COO- formed from an alcohol and carboxylic in the presence of a strong acid catalyst

72
Q

what is the equation for esters ?

A

alcohol + carboxylic acid - acid catalyst - ester + water

73
Q

what is condensation polymerisation ?

A

monomers containing 2 different functional groups, when monomers react together bonds form between them making polymer chains

74
Q

what are polyesters ?

A

dicarboxylic acids react with diols to form ester links

75
Q

what type of reaction forms polyesters ?

A

a condensation reaction

76
Q

what are the differences between addition polymerisation and condensation polymerisation ?

A
  • number types of monomer, only 1 monomer type in addition polymerisation
  • number of products, in condensation polymerisation multiple products are formed
  • functional groups in polymerisation, 2 functional groups are used in condensation polymerisation
77
Q

give an example of something which forms a naturally occurring polymer ?

A

amino acids

78
Q

what are amino acids ?

A

(NH2) - form polymers known as polypeptides

79
Q

what reaction do amino acids undergo when forming polypeptides ?

A

condensation polymerisation

80
Q

what do long chain polypeptides form ?

81
Q

what do proteins do ?

A
  • form enzymes which work as catalysts
  • forms haemoglobin which transports oxygen around the body
  • antibodies
  • tissues are made up of proteins
82
Q

why do proteins and polypeptides have different amino acids in their chains ?

A

as the order of amino acids determines the shapes/properties of proteins

83
Q

what does DNA do ?

A

carry genetic informationw

84
Q

what shape is DNA ?

A

double helix

85
Q

what are the 2 chains DNA is made up of ?

A

nucleotides

86
Q

what are the 4 bases that each nucleotide containd ?

87
Q

what do the bases in DNA do to form the DNA structure ?

A

pair up and form cross links keeping nucleotides together giving the double helix structure

88
Q

what do the order of bases determine (DNA)?

A

they act as a code for an organisms genes

89
Q

what does sugar contain ?

A

hydrogen, oxygen, carbon

90
Q

what polymers does sugar form ?

A

cellulose
starch for enzymes

91
Q

what is DNA, Sugar, and polypeptides examples of ?

A

naturally ocurring polymers

gcse science (27 decks)

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