✅6 - Organic Chemistry I Flashcards Preview

Edexcel A Level Chemistry - 2021 MMS EXAMS > ✅6 - Organic Chemistry I > Flashcards

Flashcards in ✅6 - Organic Chemistry I Deck (110)
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1
Q

What is a functional group?

A

The group of atoms which gives an organic compound its characteristic properties and reactions

2
Q

What is a hydrocarbon?

A

A compound of hydrogen and carbon only

3
Q

What is a homologous series?

A

Family of compounds which all contain the same functional group and each member of there series contains one CH2 unit more than the previous member

4
Q

What is a general formula?

A

Represents all the members of a homologous series

5
Q

Why can carbon form so many compounds?

A
  • the atoms have an exceptional ability to form chain, branches chains and rings of various sizes
  • Carbon is relatively inert and unreactive when in C-C or C-H bonds
6
Q

What is empirical formula?

A

The simplest whole number ratio of atoms in a compound

7
Q

What is molecular formula?

A

The actual number of atoms in each molecule

8
Q

What is structural formula?

A

Shows the arrangement of atoms carbon by carbon with the attached hydrogens and functional groups

9
Q

What is skeletal formula?

A

Shows the bonds of the carbon skeleton only, with any functional groups

10
Q

What is displayed formula?

A

Shows how all the atoms are arranged, and the bonds between them, drawn out

11
Q

What is addition?

A

Joining two or more molecules together to form a larger molecule

12
Q

What is polymerisation?

A

Joining together lots of simple molecules to form a large one

13
Q

What is elimination?

A

When a small group of atoms breaks away from a larger molecule

14
Q

What is substitution?

A

When one species is replaced by another

15
Q

What is hydrolysis?

A

Splitting a molecule into two molecules by adding H+ and OH- derived from water

16
Q

What is a species?

A

An atom, an ion, a radical or a molecule

17
Q

What is a nucleophile?

A

An electron pair donor, often negatively charged ions or species with a lone pair

18
Q

What are nucelophiles attracted to?

A

A delta positive Carbon

19
Q

What is an electrophile?

A

Electron pair acceptors, positively charged ions attracted to electron rich areas

20
Q

What is a radical?

A

A species with an unpaired electron

21
Q

What are structural isomers?

A

The molecular formula is the same but the structural formula is different

22
Q

What are chain isomers?

A

The carbon chain is arranaged differently

23
Q

What are positional isomers?

A

Where the functional group is attached to a different carbon

24
Q

What are functional group isomers?

A

The isomers have different functional groups

25
Q

Can atoms rotate around a C-C bond?

A

Yes

26
Q

What type of hydrocarbons are alkanes?

A

Saturated

27
Q

What are the two types of fission?

A

Homolytic and heterolytic

28
Q

What is heterolytic fission?

A

The bond breaks unevenly with one of the bonded atoms recieving both electons from the bonded pair

29
Q

What is homolytic fission?

A

The bond breaks evenly and each bonding atom receives one electron from the pair

30
Q

What does heterolytic fission produce?

A

Two ions, one + and one -

31
Q

What does homolytic fission produce?

A

Two radicals

32
Q

In what reactions do alkanes react with halogens?

A

Free radical substitution

33
Q

What are the steps of free radical substitution?

A

Initiation
Propagation
Termination

34
Q

What is photodissociation?

A

When radicals are produced by sunlight in Cl-Cl bonds

35
Q

What happens in propagation reactions?

A

Radicals are created and used up

36
Q

What can happen in propagation between methan and a chlorine radical?

A

Cl. + CH4 ——> CH3. + HCl

.CH3 + Cl2 ——> CH3Cl + Cl.

37
Q

What happens in termination reactions?

A

Radicals are used up as they react with each other

38
Q

What is the main problem with free radical substitution?

A

A mixture of products is created

39
Q

What is crude oil mainly made up of?

A

Alkanes

40
Q

What temperature is used to vaporise crude oil?

A

350 degrees C

41
Q

Why don’t the largest hydrocarbons vaporise?

A

Their boiling points are too high

42
Q

What happens to the vapour as it moves up the fractionating column?

A

It cools, and each fraction condenses at a different temperature

43
Q

What happens to the hydrocarbons with the lowest boiling points?

A

The don’t condense, they’re drawn out as gases at the top of the column

44
Q

How can the heaviest fractions be used?

A

They can be ‘cracked’ to form smaller molecules

45
Q

What are the two types of cracking?

A

Thermal and catalytic

46
Q

What are the conditions of thermal cracking?

A

1000 degrees C and high pressure (70 atm)

47
Q

What does thermal cracking produce?

A

Alkenes

48
Q

What is the catalyst in catalytic cracking?

A

Zeolite (hydrated aluminosilicate)

49
Q

What does catalytic cracking produce?

A

Aromatic hydrocarbons and motor fuels

50
Q

Why is catalytic cracking more beneficial?

A

It cuts costs, because lower pressure and temperature can be used and the reaction is sped up by the catalyst

51
Q

What can alkanes be reformed into?

A

Cycloalkanes and aromatic hydrocarbons

52
Q

What is knocking?

A

Where alkanes explode of their own accord when the fuel/air mixture in the engine is compressed

53
Q

What are the most likely hydrocarbons to cause knocking?

A

Straight chain ones

54
Q

What catalysts are used for reforming?

A

Platinum on aluminium oxide

55
Q

What state do fuels have to be in to undergo combustion reactions?

A

Gaseous

56
Q

Why do larger alkanes produce more energy per mole?

A

They have more bonds to break

57
Q

What are the issues with carbon monoxide?

A

Carbon monoxide is better at bonding with haemoglobin so less oxygen is carried around the blood stream, leading to oxygen deprivation, and this can be fatal

58
Q

What are the issues with SO2 and NOx?

A

Acid rain can be caused by the burning of fuels that contain sulfur, as the sulfur dioxide can be converted to sulfuric acid.
Oxides of Nitrogen can also cause acid rain as they are converted into nitric acid

59
Q

What is the main issue with fossil fuels?

A

They are non-renewable

60
Q

What biofuels are available?

A

Bioethanol
Biodiesel
Biogas

61
Q

How is bioethanol made?

A

By the fermentation of sugar from crops sch as maize

62
Q

How is diodiesel made?

A

By refining renewable fats and oils such as vegetable oils

63
Q

How is biogas made?

A

Produced by the breakdown of organic waste matter

64
Q

Why are biofuels classed as carbon neutral?

A

Because although they release CO2 when burnt, the plants took in CO2 as they grew.

65
Q

What are the problems with biofuels?

A

Petrol car engines have to be modified to use the fuel and land used to grow the crops then can’t be used to grow food, an issue in developing countries

66
Q

What are sigma bonds?

A

Single covalent bonds

67
Q

When is a sigma bond formed?

A

When two orbitals overlap in a straight line, giving the highest possible electron density between two positive nuclei

68
Q

What does the high electron density between the nuclei mean for sigma bonds?

A

That there is strong electrostatic attraction and so sigma bonds are the strongest

69
Q

What is a pi bond?

A

The second part of a double bond, along with a sigma bond

70
Q

How are pi bonds formed?

A

When two lobes of two orbitals overlap sideways - one above and one below the molecular axis

71
Q

What is the electron density in a pi bond like?

A

Spread out, above and below the nuclei so the electrostatic attraction is weaker and they are more easily broken

72
Q

How do strengths of double and single bonds compare?

A

A double bond is less than twice as strong as a single bond

73
Q

Can double bonds rotate?

A

No

74
Q

Why can double bonds rotate?

A

Because the p-orbitals overlap in pi bonds

75
Q

What are Z-isomers?

A

When the same groups are either both above or both below the bond

76
Q

What are E-isomers?

A

When the same groups are on opposite sides, one above and one below the double bond

77
Q

How does E/Z isomerism work when all the groups are different?

A

The atoms with the larger atomic numbers are given priority

78
Q

What are cis isomers?

A

When the groups are on the same side of the double bond, eg both above or both below

79
Q

What are trans isomers?

A

When the groups are on different sides of the double bond, eg one above and one below

80
Q

When is E/Z isomerism used?

A

When there are two high-priority groups

81
Q

When is cis/trans isomerism used?

A

When there are two groups the same, no matter of their priority

82
Q

How are dihalogenoalkanes made?

A

By reacting halogens with alkenes

83
Q

How are alcohols made from alkenes?

A

Through steam hydration

84
Q

How are diols made from alkenes?

A

Oxidation by acidified potassium dichromate

85
Q

How many products are formed when hydrogen halides are added to unsymmetrical alkenes?

A

Two

86
Q

What is Markownikoff’s rule?

A

The major product from addition of hydrogen halides to unsymmetrical alkenes is the one where the hydrogen adds to the carbon with the most hydrogens already attached (ie ones with alkyl groups)

87
Q

What do alkenes join up to form?

A

Addition polymers

88
Q

What are the different methods for disposing of polymers?

A

Waste plastics can be buried, reused or burned

89
Q

When is landfill used to dispose of plastics?

A

When they are difficult to separate from other waste
Not are not in sufficient quantities to make separation worthwhile
Too difficult to technically recycle

90
Q

How can waste plastics be reused?

A

They can be melted and remoulded

They can be cracked into monomers and resued again

91
Q

What can the burning of waste plastics be used for?

A

Generating electricity

92
Q

How can making polymers be made sustainable?

A

Use reactant molecules that are as safe and environmentally friendly as possible
Use as few other materials, eg solvents, as possible
Use renewable raw materials
Keep energy use to a minimum

93
Q

What is a primary halogenoalkane?

A

One alkyl group attached to Carbon with X bonded

94
Q

What is a tertiary halogenoalkane?

A

Three alkyl groups attached to Carbon with X bonded

95
Q

What can halogenoalkanes be hydrolysed to form?

A

Alcohols

96
Q

Why are iodoalkanes hydrolysed the fastest?

A

Iodoalkanes have the longest, weakest bonds, which are easiest to break

97
Q

How can the rate of hydrolysis of halogenoalkanes be compared?

A

Mix halogenoalkane with ethanol
Add silver nitrate
Time how long it take for precipitate to form

98
Q

Halogenoalkane + Aqueous KOH —->

A

Alcohol + KX

99
Q

Hlaogenoalkane + CN- —->

A

Nitrile + X-

100
Q

Halogenoalkane + NH3 —->

A

Amine + NH4+

101
Q

Halogenoalkane + KOH + Ethanol + reflux —->

A

Alkene + H2O + KBr

102
Q

Alcohol + PCl5 —->

A

Chloroalkane + HCl + POCl3

103
Q

Alcohol + HBr —->

A

Bromoalkane + H2O

104
Q

Alcohol + PI3 —->

A

Iodoalkane + H3PO3

105
Q

Alcohol + acid catalyst + heat —->

A

Alkene + water

106
Q

What is the simplest way to oxidise alcohols?

A

Burn them

107
Q

What can primary alcohols be oxidised to?

A

Aldehydes, then carboxylic acids

108
Q

What can secondary alcohols be oxidised to?

A

Ketones

109
Q

What can tertiary alcohols be oxidised to?

A

Nothing - they can’t be oxidised

110
Q

What is used to oxidise alcohols?

A

Acidified potassium dichromate