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A-level Chemistry <3 > 4- Basics, Hydrocarbons, Alcohols, Haloalkanes, Analysis > Flashcards

4- Basics, Hydrocarbons, Alcohols, Haloalkanes, Analysis Flashcards

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1
Q

What is the stem name for one carbon

A

Meth-

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2
Q

What is the stem name for 2 carbons

A

Eth-

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3
Q

What is the stem name for 3 carbons

A

Prop-

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4
Q

What is the stem name for 4 carbons

A

But-

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5
Q

What is the stem name for 5 carbons

A

Pent-

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6
Q

What is the stem name for 6 carbons

A

Hex-

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7
Q

What is the stem name for7 carbons

A

Hept-

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8
Q

What is the stem name for 8 carbons

A

Oct -

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9
Q

Stem name for 10 carbons

A

Dec-

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10
Q

Display formula for butane

A

CH3CH2CH2CH3

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11
Q

What is the general formula

A

An algebraic formula that can describe any member of a family of compounds

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12
Q

What is the empirical formula

A

The simplest whole number ratio of atoms of each element in a compound

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13
Q

What is the molecular formula

A

The actual number of atoms of each element in a molecule

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14
Q

What is the structural formula

A

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

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15
Q

What is the skeletal formula

A

Shows the bonds of the carbon skeleton only, with any functional group. The hydrogen and carbon atoms aren’t shown.

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16
Q

What is the display formula

A

Shows all the atoms are arranged and all the bonds between them

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17
Q

What is a homologous series

A

An organic compound with the same functional group and similar chemical properties and general formula

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18
Q

Define hydrocarbon

A

A compound made of hydrogen and carbon atoms only

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19
Q

Define staurated

A

Has the maximum number of hydrogen atoms possible (around the carbon atom in a hydrocarbon)

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20
Q

Define unsaturated

A

An organic compound with a double / triple bond capable of adding subsitiuents through addition reactions

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21
Q

Define a functional group

A

An atom of group of atoms in an organic molecule, that determines its characteristic chemical and physical properties

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22
Q

What do consecutive members of a homologous series differ by

A

-CH2-

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23
Q

What is the general formula for alkanes.

A

CnH2n+2

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24
Q

Suffix for alkanes

A

-ane

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25
Q

Prefix of branched alkanes

A

Alkyl-

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26
Q

Suffix for alkanes

A

-ene

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27
Q

Prefix for haloalkanes

A

Chloro-
Bromo-
Iodo-

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28
Q

Suffix for alcohols

A

-ol

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29
Q

Suffix for aldehydes

A

-al

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30
Q

Suffix for ketones

A

-one

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31
Q

Prefix + suffix for cycloalkanez

A

Cyclo-….. -ane

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32
Q

Suffix for carboxylic acids

A
  • oic acid
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33
Q

Prefix and suffix for esters

A

Alkyl-…..-anoate

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34
Q

All organic compounds contain a carbon skeleton - what are the 2 ways this can be

A

Aromatic or aliphatic

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35
Q

What do aromatic compounds contain

A

Benzene ring

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36
Q

What ao aliphatic compounds contain

A

Carbon, hydrogen

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37
Q

How are aliphatic compounds joined together

A

joined together in straight chains, branched chains or non-aromatic rings

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38
Q

If an aliphatic compound contain a (non aromatic) ring then it can be callled …..

A

Alicyclic

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39
Q

What are saturated compounds

A

Only contain carbon-carbon single bonds

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40
Q

What do unsaturated compounds have

A

Carbon -carbon double bonds, triple bonds or aromatic groups

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41
Q

What is an alkyl group

A

A fragment of a molecule

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42
Q

What is the general formula for an alkyl group

A

CnH2n+1

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43
Q

What does rhe main functional group of the molecule usually tell you….

A

What Homologous series the molecule is in, and gives the prefix or suffix

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44
Q

If there is more than one longest chain when naming organic compounds what do you do

A

Pick the one with the most side chains

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45
Q

What order do you put the prefix on IUPAC names

A

In alphabetical order, after the number of the carbon atom each is attached to

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46
Q

If there is more that one identical side chain or functional group. What do you use before that part of the name

A

2 (di-)
3( tri-)
4 (tetra-)
(Ignor these when factoring the alphabetical order)

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47
Q

When are two molecules isomers of one another

A

They have the same molecular formula but the atoms are arranged differently

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48
Q

What are the two types of isomers (organic)

A

Structural isomers
Stereoisomers

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49
Q

What is a structural isomer

A

The atoms are connected in differnt ways. So although the molecular formula is the same, the structural formula is differnt.

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50
Q

How many differnt types of structural isomers are there

A

3

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51
Q

What are the 3 types of structural isomers

A

Chain isomers
positional isomers
Functional group isomers

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52
Q

What is a chain isomer

A

The carbon skeleton can be arranged differnt, eg. A straight chain or branched in differnt ways

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53
Q

What are the properties like in chain isomers

A

Similar chemical properties but there physical properties like boiling points will be differnt because of the change in shape of the molecule

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54
Q

What is a positional isomer

A

The skeleton and rhe functional group could be the same, only with the functional group attached to a differnt carbon atom

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55
Q

Explain the properties in positional isomers

A

Differnt physicals properties
And the chemical properties might be differnt to

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56
Q

What are functional group isomers

A

The same atoms can be arranged into differnt functional groups

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57
Q

Explain the properties in functional group isomers

A

Very differnt physical and chemical properties

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58
Q

How many chain isomers are there with C3H7Br

A

0

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59
Q

How many positional isomers are there with C3H7Br
What are they

A

2 isomers
1-bromopropane
2-bromopropane

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60
Q

What are alkanes

A

saturated hydrocarbons
Every carbon atom has 4 single bonds with other atoms

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61
Q

What is the general formula for alkanes

A

CnH2n+2

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62
Q

What is the general formula for cyclo….ane

A

CnH2n

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63
Q

What is the shape of Alkane molecules around each carbon

A

Tetrahedral

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64
Q

What is the bond angle in alkanes

A

109.5

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65
Q

What are the boiling points like in alkanes

A

Smallest alkanes are gases at room temp and pressure as they have got a very low boiling point

larger alkanes are liquids they have a higher boiling points

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66
Q

Explain the difference in boiling points between small and large alkanes

A

1) alkanes have covalent bonds inside the molecules. Between the molecules there are induces dipole -dipole interactions (London forces) which hold them together
2) the longer the carbon chain,the strong the London forces. This is becuase there’s more surface contact and more electrons to interact with
3)as the molecule get longer it takes more energy to overcome the London forces and the booing points rise

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67
Q

Explain the differnce in boiling points between branches and unbranched alkanes

A

Branches chains Has a lower boiling points than its straight chain isomer. Branched chain alkanes can’t pack closely together and they have smaller molecular surface areas of contact. However straight chains can pack closely and there is a lot of surface contact between them so the London forces are reduced in branched chains.

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68
Q

If you oxidise (burn) alkanes with oxygen what do you get and what is the name of this reaction

A

Carbon dioxide and water
Combustion

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69
Q

Combustion equation

A

Alkane + oxygen = carbon dioxide + water

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70
Q

What do combustion reaction happen between

A

Gases
So liquid alkanes have to be varporised first

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71
Q

Smaller alkanes turn into gases ………. How else can this be described.
And what does that mean for how easy it will burn

A

More easy
(There more volatile)
it will burn more easily too

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72
Q

Larger alkanes release more energy per mole beacuse….

A

Because they have more bonds to react

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73
Q

Why are alkanes food fules

A

Lots of energy when they burn

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74
Q

All bases at the same temp and pressure have the same……

A

Molar ratio

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75
Q

How do you use the ratio of the volumes of the gases reaction together to calculate the molar ratio and therefore what hydrocarbon is combusting

A

1) using volumes provided, write the reaction equation
2) simplify
3) fill in the blanks with with you know. For example if 8 moles of o2 reacted to form 5 mole of carbon dioxide the rest of the mole must end as h20
4) use the final combustion equation to identity x
5) all the carbon atoms from x end up in carbon dioxide molecules and all the hydrogen most end as water

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76
Q

What does burning alkanes in limited oxygen produce

A

Carbon monoxide

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77
Q

Why is carbon monoxide poisonous

A

The oxygen in your blood stream is carried around by heamoglobim
Carbon monoxide is better at binding to haemonolobin than oxygen is so it binds to the heamoglobin in your blood stream before oxygen can
Thus means that less oxygen can be carried around your body leading to oxygen deprivation. At high concentrations, carbon monoxide can be fatal

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78
Q

What is an isomer

A

Molecules with the same molecular formula but differnt structural or spatial arrangementsof the atoms within the molecule

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79
Q

What are the 2 types of isomers

A

Structural
Sterioisomerism

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80
Q

What is a structural isomer

A

Same molecular formula but differnt structural formula

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81
Q

What is a position isomer

A

Molecule stays the same but the position of the functional group changes

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82
Q

Suffix for naming alcohols

A

Ol

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83
Q

When the alcohol group is not priority what is it called

A

Hydroxyl group

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84
Q

Where is the functional group on an aldehyde

A

Always on the terminal c atom ( so we don’t give a numerical position

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85
Q

Ketones suffix

A

-one

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86
Q

Suffix of haloalkanes

A

Ane

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87
Q

Alkenes suffering

A

Ene

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88
Q

What has the lowest priory when naming

A

Alkane and haloalkes

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89
Q

What has a higher priority in m,wind alchol or alkanes

A

Alcohol

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90
Q

When there is a alkene and a alcohol functional group how is it written

A

……… en ……- - ol

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91
Q

What has more priority a functional group or lowest numbers

A

Functional group

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92
Q

What are the two types of bond fissions

A

Homolytic
Heterolytic

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93
Q

What is bond fission

A

Breaking a covalent bond

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94
Q

What is heterolytic fission

A

In heterolytic fission the bond breaks unevenly with one of the bonded atoms recieving both electrons from the bonded pairs
Two differnt substances are formed - a positively charged cations and a negatively charged anion

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95
Q

What does a Curley arrow show

A

Movement of an electron pair

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96
Q

What is homolytic fission

A

The bond breaks evenly and each bonding atom recives one electron from the bonded pair. Two electrically charged ‘radicals’ are formed

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97
Q

What is a radical and how are they shown

A

A particle that have an unpaired electron
They are shown in mechanisms by a big dot next to the molecular formula (the dot represents the unpaired electron )

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98
Q

Are radicals reactive and why

A

Very
Because of the unpaired electrons

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99
Q

For which functional groups is it always on carbon 1

A

Aldehydes
Carboxylic acid
Nitriles

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100
Q

Does a high priority take the suffix or a prefix
Except form what

A

Suffix and lowest number
Double and triple c-c bonds only take suffic form

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101
Q

What is the order of the highest naming priority

A

Carboxylic acid > aldehydes > ketones > alcohols > alkenes > haloalkanes

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102
Q

If more than one double bond presents in an alkane , what happens to the name

A

DIene
TRI
And stem ends in a

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103
Q

What is the prefix for haloalkanes - fluorine

A

fluoro

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104
Q

What is the prefix for haloalkanes - chlorine

A

Chloro

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105
Q

What is the prefix for haloalkanes - bromine

A

Bromo

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106
Q

What is the prefix for haloalkanes - iodine

A

Iodo

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107
Q

When there are more than 2 OH groups
How does it change the name

A

Di or tri used
And an e on the stem name

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108
Q

If there is a alcohol and another functional group with a higher priority what is rhe alcohol called as a prefix

A

Hydroxy

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109
Q

What changed about the name when there are two aldehydes groups

A

Di
And an e is added to the stem.

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110
Q

What changes about the name when there are two ketones groups

A

Di
And an e is added to the stem

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111
Q

If there are Carboxylic acid groups on both ends of the chain
What is it called

A

Dioic acid

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112
Q

Halogens react with alkanes forming …….

A

Haloalkanes

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113
Q

Halogens react with alkanes in ………….. reactions

A

Photochemical

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114
Q

What are photochemical reactions starts by

A

Ultraviolet light

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115
Q

Describe a photochemical reaction

A

A hydrogen atom is substituted by chlorine or bromine

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116
Q

A hydrogen atom is substituted by chlorine or bromine
What’s is this reaction called

A

Free radical substitution

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117
Q

What is rhe 3 reaction mechanisms for free radical substitution with chlorine and methane

A

Initiation reaction
Propagation reactions
Termination reaction

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118
Q

What is initiation reaction
(With Chlorine and methane as an example )
Free radical substitution

A

1) sunlight provided enough energy. To break the cl-cl bond
This is photodissociation
Cl2 —-> 2cl.

2) the bonds splits equally and each atom gets to keep one electron x homolytic fission
The atoms becomes a highly reactive free radical becasue of its unpaired electron

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119
Q

What is it called when sunlight provids enough energy to break the cl-cl bond

A

Photodissociation

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120
Q

What is propagation reaction
(With Chlorine and methane as an example )
Free radical substitution

A

Free radicals are used to and created in a chain reaction
1) cl. Attacks a methane molecule : ch. + ch4 —> .ch3 + hcl
2) the new methyl free radical, , .ch3, can attack another cl2 molecule. : .CH3 + Cl2 —-> CH3Cl + Cl.
3) the new Cl. Can attack another ch4 molecule and so on until all the Cl2 or ch4 molecules are wiped out

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121
Q

What is a termination reaction
(With Chlorine and methane as an example )
Free radical substitution

A

1) the two free radicals join together, making a mole stable molecule,
2) there are heaps of possible termination reactions. Examples.
Cl. +.CH3 —> CH3CL
.CH3 + .CH3 —> C2H6
Cl. + Cl. —> cl2

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122
Q

What is a problem with free radical substitution

A

If your trying to make a particular product , you don’t get only the product your after but a mixture of products

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123
Q

General formula for alkenes

A

Cn H2n

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124
Q

What do au alkenes molecules have

A

At least one c=c double covalent bond

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125
Q

Are c= c double bonds unsaturated + why

A

Yes
Because they can make more double bonds with extra atoms in addition reactions

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126
Q

A double bund is made up of what two bonds

A

Sigma and pi

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127
Q

When is a sigma bond formed

A

When two s orbitals overlap

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128
Q

Explain what happens when two s orbitals overlap

A
  • They overlap in a straight line.
    This gives the highest possible electron density between two nuclei - this is a single covalent bond
    The high electron density between the nucleus means there is a strong electrostatic attraction between the nuclei and the shared pair of electrons . This means that sigma bond have a high bond enthalpy
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129
Q

What is the strongest type of covalent bonds

A

Sigma bond

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130
Q

When is a pi bond formed

A

sideways overlap of two adjacent p orbitals

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131
Q

Whya have pi bonds got two parts to it

A

One above and one bellow the molecular axis. This is because the p orbitals which overlap are dumbbell shaped

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132
Q

Why are pi bonds weaker than sigma bonds

A

Because the electron density is spread out above and below the nuclei. This means that the electrostatic attraction. Between the nuclei and shared pair of electrons. Is weaker so pi bonds have a relatively low bond enthalpy

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133
Q

Are C-C and C-H sigma or pi bonds

A

Sigma

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134
Q

Why don’t alkanes react easily

A

Only contain C-C and C-H sigma bonds which have high bond enthalpy and so are difficult to break.
The bonds are non polar do they don’t attract nucleophiles or electrophiles

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135
Q

Why are alkenes more reactive

A

The C=C bonds contains both sigma and pi bond
The C=C double bond contains four electrons so it has a high electron density and the pi bond also sticks out above and below the rest of the molecule. These two factors means rhe pi bonds is likely to be attacked by electrophiles.
The low bond enthalpy of the pi bond also contributes to the reactivity .

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136
Q

Why are alkenes good starting points for making other organic compounds

A

Because the double bond is so reactive

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137
Q

What are alkenes good starting points for

A

Organic compounds and for making petrochemicals

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138
Q

can double bonds rotate

A

Yes

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139
Q

How are atoms arranged in a C=C double bond

A

1) Carbon atoms in a C=C double bond and the atoms bonded to these carbons all lie in the same plane (they’re planar).
Because of the way they’re arranged, they’re actually said to be trigonal planar — the atoms attached to each double-bonded carbon are at the corners of an imaginary equilateral triangle.

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140
Q

What are the bond angles in the planar unit

A

All 120°

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141
Q

Are all alkenes completely planar

A

In ethene yes

But not in larger alkenes
But the >C=C< unit is still planar

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142
Q

Why can’t C=C atoms around it rotate

A

Because of the way the p orbitals overlap to form a pi bond

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143
Q

Are double bonds rigid

A

Yes

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144
Q

Even though atoms can’t rotate about a double bonds, they can still rotate …..

A

About any single bond in a molecule

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145
Q

The restricted rotation around the C=C double bond is what causes alkenes to form, ……

A

Stereoisomers

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146
Q

What is a stereoisomers

A

Have the same structural formula but a differnt arrangement in shape

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147
Q

When do stereoisomers occur

A

When two double bonded carbon atoms each have two differnt atoms or groups attached to them

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148
Q

What are the names of the stereoisomers

A

Z-Isomer
E- isomer

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149
Q

What is a Z-isomer

A

Same group either both above or below the double bond

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150
Q

What is the E-isomer

A

The same group positioned across the double bond

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151
Q

How Is the E and Z separeated from the name when naming stereoisomers

A

By a dash

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152
Q

Who came up with the solution to the problem with stereoisomers having totally differnt groups attached

A

Mr cahn
Mr ingold
Mr prelog

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153
Q

What is the name for the rules used to work out which is E or Z isomers for any alkenes

A

Cahn-ingold-prolog (CIP) rules

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154
Q

How does CIP rule name E and Z isomers

A

Looks at the atoms directly bonded to each of the C=C carbon atoms
Atoms with the higher atomic number of each carbon is given the higher priority

You can now assign the isomers as E and Z.
if the 2higher priority groups are positioned across the double bond from one another is the E isomer

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155
Q

If a carbon is directly bonded to two carbon atoms, what do u do when looking if E or Z isomers

A

you need to go further along the chain to work out ordering
The methyl carbon is only attached to the hydrogen atom but ethyl carbon is attached to another carbon atom so the ethyl group is high priority

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156
Q

What can E/Z isomers also be known as

A

Cis - trans isomers

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157
Q

of the carbon atoms have at least one group in common then you can call the isomers what …..

A

Cis or trans
Or
E- or Z-

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158
Q

What does cis means for naming stereoisomerism

A

The same groups are on the same side of the double bond

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159
Q

What does trans mean in naming stereoisomers

A

the same groups are on opposite side of the double bond

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160
Q

When does the cis - trans system not work

A

If the carbon atoms both have totally differnt groups attached to the,

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161
Q

What is an optical isomer

A

A special kind of stereoisomerism that occurd when there is an asymmetrical carbon with an organic molecule - called a chiral carbon

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162
Q

WHat is a chiral carbon

A

Carbon with 4 different substituents bonded to the centre carbon atom - so no line of symmetry

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163
Q

Asymmetrical molecules arise due to the chiral carbon what does it give rise to

A

Two isomers (non-superimposable mirror images)
They are optical isomers

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164
Q

What are the two optical isomers known as

A

Enatiomers of each other
(Oftern with a + or - depending on how they effect the plan of polarised light)

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165
Q

Each enatiomer of a chiral molecule will rotate the plan of polarises light by …..

A

90°

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166
Q

+ enantimer - rotates the plane by 90°………..

A

Clockwise

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167
Q

-enantimer - rotates the plane by 90°………..

A

Anti-clockwise

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168
Q

If a 50:50 enantiomer split what is it called

A

Racemic

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169
Q

Aliphatic

A

Carbon atoms are joined to each other in branched or unbranched chains or non aromatic rings

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170
Q

Alicyclic

A

Carbon atoms are joined to each other in ring structures

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171
Q

Aromatic

A

Some or all the atoms are joined in a benzene ring

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172
Q

What is the bonding in alkanes

A

Bond is the result of the overlap between two orbitals of the bonding atoms ( sigma bonds)
Each carbon atoms have 4 sigma binds

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173
Q

What is the shape of alkanes and the bong angle

A

Tetrahedral
109.5 °

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174
Q

Why are alkane shapes flexible

A

The sigma bond lie between the two atoms in a horizontal plane and there is free rotation

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175
Q

Describe of a sigma bond in alkanes

A

One SP3 orbital form each carbon overlap to form a single c-c bond called a sigma bong

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176
Q

What is this called
1S2 2S2 2p2 ——-> 1s2 2s1 2p3

A

Hybridisation

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177
Q

How does boiling point change as the carbon chain increases in alkanes

A

Increases

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178
Q

Why does boiling point increase as chain length of alkanes increase

A

As chain length increases the molecule will have a larger surface area
This is greater constant between molecules
London forces between molecules are therefore greater

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179
Q

How does branching of alkanes effect boiling points

A

Branched chain compounds have lower boiling points than the corresponding straight chain isomer
The London forces depend on the surface area of contract, it becomes smaller on account of branching so the boiling point of the branched chain alkenes are less than the straight chain isomers

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180
Q

Are alkanes soluble in non polar substances and why

A

Yes
They are non polar
They interact and from new London forces overcoming the old ones

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181
Q

Are alkanes soluble in polar solvents and why

A

No
They are non polar
A lot of energy is required to overcome the hydrogen bonding in water, any interaction of alkane and water will only result in new London forces + this is not energetically equivalent to overcoming the old London forces and hydrogen bonding

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182
Q

What are electrophilic addition reactions

A

The alkene double bond opens up and atoms are added to the carbon atom

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183
Q

Why do electrophilic addition reactions happen

A

The double bond has got plenty of electrons and is easily attacked by electrophiles

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184
Q

What are electrophiles

A

Electron pair acceptors
They are usually shot of electrons so they’re attracted to areas where there are lots of electrons

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185
Q

Give some examples of electrophiles

A

Positive charged ions
Like H+
And polar molecules

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186
Q

What does adding hydrogen to C=C bond produce

A

Alkanes

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187
Q

What are the conditions for addinf hydrogen to a C=C double bond to produce an alkane
(Hydrogenation )

A

Nickel catalyst
150°c

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188
Q

Halogens react with Alkenes to form what

A

Dihaloalkanes

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189
Q

Describe halogenation

A

The halogen is added across the double bond. And each of the carbon atoms end up bonded to one halogen atom

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190
Q

What type of reaction is halogenation

A

Electrophilic addition

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191
Q

Describe the mechanism of halogenation
With bromine and ethene as an example

( how would this be differnt for H-Br)

A

The double bond repels the electrons in br2 polarising Br-br

Heterolytic fission of Br2. The closer Br gives up the bonding electron to the other br and bonds to the C atom

You get a positively charged carbocation intermediate. The Br- now goes over and bonds to the other c atoms forming 1,2-dibromoethane

H-br aleardy has a permanent dipole so step one isn’t necessary

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192
Q

How can u test for carbon carbon double bonds

A

Add bromine water
Shake
Colour changes orange to colourless

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193
Q

Why does adding bromine water to an alkene decolourise

A

Becuase bromine is added across the double bond to form a colourless dibromoalkane

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194
Q

Alkenes can be hydrated by steam to form what

A

Alcohols

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195
Q

What is the reaction from Alkenes to alcohol called

A

Hydration

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196
Q

What conditions are needed for hydration reaction

A

300°c
Pressure 60-70 atm
Solid phosphoric (v)acid catalyst

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197
Q

Is the hydration reaction of Alkenes to Alcohols reversible and what is the reaction yield like

A

Yes
Low (It’s only around 5% from ethene but u reacted alkene gas can be recycled and up ethene yield to around 95%)

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198
Q

Alkenes undergo addition reactions with hydrogen haldies to form what

A

Haloalkanes

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199
Q

If hydrogen halides add to an unsymmetrical alkene how many possible products are there
And what does rhe amount of each product depend on

A

2
How stable the carbocation formed in the middle of reaction is

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200
Q

Are carbocations with more alkyls groups more or less stable and why

A

More because the alkyl group feeds electrons towards the positive charge. So the more stable carbocations is more likely to form

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201
Q

What is a primary/secondary/tertiray carbocation

A

Refers the the number of r groups
Primary = 1 r groups
Tertiray = 3 r groups

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202
Q

Order primary , secondary and tertiray carbocations into leats to most stable

A

Primary
Secondary
Tertiray

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203
Q

How does hydrogen bromine react with propene

A

1) the secondary carbocation is more stable because it’s got two alkyl groups
This carbocation forms more of the time

2) the primary carbocation is less stable as its only got one alkyl group it forms less oftern

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204
Q

What is rhe markownikoff rule

A

The major product form addition of a hydrogen halide (HX) to an unsymmetrical alkene is the one where hydrogen adds to the carbon with the most hydrogen already attached

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205
Q

Describe complete combustion

A

Plentiful supply of O2
Alkanes burn completely
Products = co2 and H2O

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206
Q

Products of complete combustion

A

CO2 and H2O

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207
Q

Describe incomplete combustion

A

Limited supply if O2
Less energy released per mole than complete
Leads to C or CO

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208
Q

What are the products of incomplete combustion

A

C or CO
And water

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209
Q

Why are alkanes good fules

A

Readily available
Easy to transport
Burn in plentiful supply of O2 without producing toxic products
Highly exothermic when combusted

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210
Q

What are the harms of CO

A

Highly toxic
Odourless
causes death if accumulated in an enclosed space
Toxic to humans

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211
Q

Why is carbon monoxide toxic to humans

A

Binds with haemoglobin in RBC to from carboxyhaemoglobin ( a stronger bond than that between oxygen and haemoglobin)

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212
Q

Symptoms of carbon monoxide poisoning

A

Tension headaches
Dizziness
Nausea
Vomiting
Tiredness
Confusion
Stomach pain
Difficulty breathing

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213
Q

What does rhe % level of carboxyhaemoglobin have to be to indicate severe exposure to carbon monoxide

A

30%

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214
Q

Treatments of carbon monoxide

A

Breathing in conc O2 and hyperbaric oxygen therapy

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215
Q

What is another word for carbon

A

Soot

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216
Q

Why is carbon not a desirable product

A

Global dimming - carbon particles reflect sunlight back into space
Health - soot can enter body (leads to breathing issues)

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217
Q

The double bond in alkenes can opem up and join together to make long chains called …..?

A

Polymers

218
Q

Individual small alkenes are called…. (Before joined together to form polymers)

A

Monomers

219
Q

How are monomers joined together to form polymers

A

Addition polymerisation

220
Q

How to find the monomer form a polymer

A

Take the repeating unit and add a double bond

221
Q

Advantages of synthetic polymers

A

Very unreactive so food doesn’t react with the PTFE coating on plans, plastic window don’t rot.

222
Q

What is the problem of polymers being very unreactive

A

Most polymers arnt biodegradable and so they’re very difficult to dispose of

223
Q

In the Uk how many tonnes of plastic waste are produced each year

A

Over 2 million tonnes

224
Q

What 3 ways can u dispose of water platics

A

Buried
Reused
Burned

225
Q

When is plastic generally disposed of in landfill

A

Used when rhe plastic is
- difficult to separate from other waste
- not in sufficient quantities to make separation financially worthwhile
- too difficult technically to recycle

226
Q

Why is there a need to reduce landfill as much as possible

A

Because the amount of waste we generate is become more of a problem

227
Q

What are many plastics made from

A

Non renewable
Oil fractions

228
Q

What are ways to reuse plastics after sorting into differnt types

A

Some plastic can be recycled by melting and remoulding them

Some plastics can be cracked into monomers, and these can be used as an organic feedstock to make more plastics or other chemicals

229
Q

What can the heat generated from burning plastics be used to do

A

Generate electricity

230
Q

Why does burning plastcis need to be carefully controlled

A

to reduce toxic gases
(Eg, polymer that contain chlorine produce HCL when burned)

231
Q

What are waste plastics from, combustion passed through and why

A

Scrubbers which can neutralise gases such as HCl by allowing them to react with a base

232
Q

What can biodegradable polymers be made from

A

Renewable raw materials such as starch ( from maize and other plants) or oil fractions, such as from the hydrocarbon isoprene (2-methyl-1,3-butadiene)

So organisms can digest them

233
Q

Negative of biodegradable,e polymers

A

More expensive than the non biodegradable equivalents

234
Q

Why cant u just put biodegradable polymers in landfill and expect them to perish away
And where would u need to put them

A

lack of moisture and oxygen

Compost heap - so u would have to collect and separate the biodegradable polymers from non biodegradablepolymers

235
Q

Give a potential use of biodegrable plastic

A

Plastic sheeting used to protect plants from the frost can be made from poly(ethene) with starch grains in bedded in it in time the start is broken down by microorganisms and the remaining poly(ethene) crumbles into dust. There is no need to collect dispose of the old sheeting.

236
Q

What are photodegradable polymers

A

Polymers that decompose when exposed to sunlight

237
Q

What is a radical

A

A species with an unpaired valence electron

238
Q

What is a mechanism

A

The steps undergone by a chemical reaction as it is occurring

239
Q

What is a Nucleophile

A

A species that donates a pair of electrons
( is attracted to a positivity centre)

240
Q

What is an Electrophile

A

A species that accepts a pair electrons
(Electron loving)

241
Q

What does propagation
(FRS) mean

A

Intermediate step (s) in a chain of reaction where the product of one reaction will undergo further reactions

242
Q

Problem pf free radical substitution on longer chains

A

The substitution could take place anywhere on a longer chain
Giving lots of products alongside the desired product (lowering the yield)

243
Q

Why is free radical substitution an issue

A

Chlorofluorocarbons (CFCs) destroy the ozone layer
In the atmosphere Cl-cl binds break (in precedes of Uv light ) by homolytic fission on to from chlorine free radicals
These radicals destroy the ozone layer

244
Q

Uses of CFCs

A

Coolants in fridges
Degreasing circuit boards
Propellants in aerosols
Dry cleaning solvents

245
Q

What is the layers of the atmosphere
+ distance from earth

A

Exosphere - 400km
Thermosphere - 300km
Mesosphere - 50km
Stratosphere and- 40km
Troposphere - 10km

246
Q

Between what two layers is the ozone layer

A

Mesosphere and stratosphere

247
Q

What are dangers of UV radiation

A

damages DNA
Chases skin cancer

248
Q

What UV radiation does the ozone absorb

A

UV-c and most of UV-B

249
Q

What is rhe Montreal protocol

A

In 1987, 24 countries signed up the Montreal protocol to ban uses if CFCs

250
Q

Alternatives to CFC and why.

A

HFC- hydrogenfluorocarbons (H,F,C)
No Cl so no ozone depletion potential

251
Q

Explain initiation of CFc

A

CFCs rise to the stratosphere
UV light provides energy to break Cl-cl bonds to from Cl. radicals

252
Q

Cl. Radial,s react to destroy the ……… in a …… reaction

A

ozone
Chain

253
Q

How many O3 molecules can one Cl. Radicals destroy

A

1000

254
Q

What are the propagation reaction for Cl. Radicals and rhe ozone layer

A

O3 + Cl. —> o2 + Cl.O
O3 + CL.O—> 2O2 + Cl.

255
Q

What is the overall reaction for Cl. Radical and the ozone layer

A

2O3 —> 3 O2

256
Q

What is thermal cracking

A

Long chain alkanes are heated to a very high temperature, extremely high pressure for a very short space of time

257
Q

Conditions of thermal cracking

A

1000-1200K
70 Atm

258
Q

Thermal cracking products

A

Shorter chain alkanes + are rich in alkenes

259
Q

What is catalytic cracking

A

Long chain alkanes heated with pressure in the presence of a zeolite catalyst.

260
Q

conditions of catalytic cracking

A

800-1000k
1-2 atm
Zeolight catalyst

261
Q

What is a zeolite catalyst

A

An acidic mineral which has a honeycomb structure made from aluminium oxide and silicon dioxide

262
Q

Products of catalytic cracking

A

Branched alkanes
Cycloalkanes
Aromatic compounds

263
Q

What is the best way to reduce chances of too many bi products for chlorine and methane

A

Excess of methane
As there is a greater chance of a chlorine colliding with methane molecule and not a chloromethane

264
Q

What products from further substitution can u get with Cl and methane

A

CH2Cl2
cHCl3
ccl4

265
Q

What is the general formula for alcohol

A

CnH2n+1OH

266
Q

What categories can alcohol be fitted into

A

Primary
Secondary
Tertiary

267
Q

What does weather alcohol is primary secondary or tertiary depend on

A

Which carbon atom the - OH group is bonded to
Primary = 1 alkyl group
Secondary - 2 lamely groups
Tertiary = 3 alkyl groups
(From where the OH is connected to the carbon)

268
Q

Are alcohols generally polar molecules

A

Yes

269
Q

Why are alcohols generally polar molecules

A

Due to the electronegative hydroxyl group which pulls electrons in the C-OH bond away form the carbon atom
d

270
Q

How do hydrogen bonds arise between alcohols

A

The electronegative oxygen in the polar hydroxyl group draws electron density away from the hydrogen, giving it a slightly positive charge. Thus positive charge can attract the lone pairs on an oxygen from a neighbouring molecule, forming hydrogen bonds

271
Q

Are alcohols soluble in water

A

Small alcohols are but larger alcohols solubility in water decrease

272
Q

Why are small alcohols soluble in water

A

When you mix alcohol with water, hydrogen bonds form between -OH and H2O. If it’s a small alcohol hydrogen binding lets it mix freely with water

273
Q

What are larger alcohols less soluble in water

A

Most of the molecule is a non polar carbon chain , so there’s less attraction for the polar H2O molecules.

274
Q

What is the trend in alcohol size and solubility in water

A

As alcohols increase in size, their solubility in water decreases

275
Q

Why do alcohols have relatively low volatility compared to non polar compound

A

As alcohols also from hydrogen bonds with each other,
Hydrogen bonding is the strongest kind of IMF so it gives alcohols relatively low volatility’s

276
Q

What does low volatiles mean

A

They don’t evaporate easily into a gas

277
Q

Alcohols react with compounds containing halide ions in what type of reaction

A

Substitution reaction

278
Q

Explain how a haloalkane is formed
Form an alcohol

A

The hydroxyl group is replaced by the halide

279
Q

What conditions are needed for alcohols to turn to haloalkanes

A

Acid catalyst

280
Q

What is formed when water is eliminated form alcohols

A

Alkenes

281
Q

What type of reaction is alcohols to alkenes

A

Elimination reaction

282
Q

How is an alcohol turned to an alkene

A

With an acidic catalyst - either concentrated sulfuric acid or concentrated phosphoric acid. The mixture is then heated

283
Q

An elimination reaction where water is eliminated is called what

A

A dehydration reaction

284
Q

When an alcohol dehydrates it eliminates what

A

Water

285
Q

What is rhe water molecule made up from when an alcohol dehydrated to an alkene
And what does this mean for the number of possible alkene products

A

From rhe hydroxyl group and a hydrogen atom that was bonded to a carbon atom from adjacent to the hydroxyl carbon

2 possible alkene products form one elimination reaction depending on which side the hydroxyl group of the hydrogen is eliminated from (if the alkene product can from E/Z isomers then the product will be a mixture of both isomers)

286
Q

What is the simplest way to oxidise alcohols

A

Burn them
Doesn’t take much to set ethanol alight and burn with a pale blue flame.

287
Q

How is ethanol oxidised

A

The C-C and C-H bonds are broken as the ethanol is complety oxidised

288
Q

What are the products of ethanol being complete oxidised and what type of reaction is this

A

Co2 and water
Combustion

289
Q

What is rhe equation for the complet oxidation of ethanol

A

C2H5O + 3O2 —> 2CO2 + 3H2O

290
Q

What can you do to mildly oxidise alcohols

A

Oxidising agent acidified dichromate (Vl)
(Cr2O7 2- / H+)

291
Q

The organe dichromate (Vl) ion is reduced to the …….

A

Green chromium (lll) ion (Cr 3+)

292
Q

What are primary alcohols oxidised to

A

Aldehydes and then to carboxylic acids

293
Q

What are secondary alcohols oxidised to

A

Ketones only

294
Q

What are tertiary alcohols oxidised to

A

They won’t be oxidised

295
Q

What are aldehydes and keystones

A

Carbonyl compounds

296
Q

What is the functional group for aldehydes and ketones

A

C=O

297
Q

What is the general formula for aldehydes and ketones

A

CnH2nO

298
Q

What do aldehydes have

A

Hydrogen and one alkyl group attached to the carbonyl carbon atom

299
Q

What do ketones have

A

2 alkyl groups attached to the carbonyl carbon atom

300
Q

How many times can primary alcohols be oxidised

A

2 x

301
Q

How to turn aldehyde into carboxylic acid

A

Oxidise
(Reflux)

302
Q

How can you control how far an alcohol is oxidesed

A

By controlling the reaction conditions

303
Q

If you gently heat ethanol with potassium dichromate (Vl) solution (an oxiditising agent) and sulfuric acid what should you get,
And if u heat to far as it’s hard to control the amount of heat what do u get

A

Apple smelling Ethanal (an aldehyde)
Usually oxidised to form vinegar smelling ethanoic acid

304
Q

How can you just form an aldehyde form a primary alcohol without it oxidising further into a carboxylic acid

A

You need to get it out of the oxidising solution as soon as it’s formed, you can do this by gently heating excess alcohol with a controlled amount of oxidising agent in distillation apparatus so the aldehyde (which boils at a lower temp than the alcohol) is distilled off immediately.

To produce carboxylic acid the alcohol has to be vigorously oxidised. The alcohol is mixed with excess oxidising agent and heated under reflux

305
Q

How are secondary alcohols oxides to ketones

A

Refluxing a secondary alcohol with acidified dichromate (Vl) will produce a ketone

306
Q

Why cant secondary alcohols be oxidised twice

A

1st oxidation produced a ketone
Ketones can’t be oxidised easily so even prolonged refluxing won’t produce anything more

307
Q

Tertiary alcohols don’t react with potassium dichromate (Vl) so the solution stays

A

Orange

308
Q

What is the only way to oxidise tertiary alcohols

A

By burning them

309
Q

What is a haloalkanes

A

Am alkane with at least one halogen atom in place of a hydrogen atom

310
Q

Why is rhe carbon halogen bond polar

A

Halogens are generally much more electronegative than carbon

311
Q

The positive carbon in a carbon halogen bond is electron deficient. What does this mean it can be attacked by

A

A Nucleophile

312
Q

What is a Nucleophile

A

An electron pair donor
It could be a negative ion or an atom with a lone pair of electrons. It donated an electron pair to somewhere without enough electrons

313
Q

OH-, CN- and NH3 are all ………. Whuchreact withhaloalkanes

A

Nucleophile

314
Q

T or f
Water is a nuceophile that reacts fast

A

False it reacts slowly

315
Q

Haloalkanes can be hydrolysed to …….

A

Alcohols

316
Q

Haloalkanes can be hydrolysed to alcohols in what type of reaction

A

A nucleophilic substitution reaction

317
Q

Explain how haloalkanes can be hydrolysed to alcohols in a nucleophilic substitution reaction

A

Use warm aqueous alkali
(Eg, sodium hydroxide or potassium hydroxide or it won’t work)

318
Q

What is hydrolysis

A

When water breaks bonds

319
Q

What is the general equation for haloalkanes to alcohols

A

R-X + OH- ————- > R-OH + X-
OH- / H20
(Reflux)

320
Q

What is the mechanism for haloalkes being hydrolysed to alcohols
(With bromoethane as an example)

A

1) OH-is the Nucleophile which provides a pair of electrons for the positive Carbon
2) the C-Br bond breaks heterolytically- both electrons from the bond are taken by the br-
3) br- falls of as OH- bonds to the carbon

321
Q

Will water work as a Nucleophile in the haloalkes to alcohols reaction

A

Yes but slower

322
Q

What is the general equation for haloalkanes with water to from alcohols

A

R-X + H2O —> R-OH +H+ + X-

323
Q

How quickly differnt haloalkanes are hydrolysed depends on what

A

Bond enthalpy
Weaker carbon halogen bonds break more easily - so they react faster

324
Q

What has the weakest bond and so hydrolysed rhe fasted in carbon-halogen bonds

A

Iodoalkanes (the further down the group the weaker bonds) have the weakest bonds so they hydrolyse the fastest

325
Q

What has the strongest bond and so hydrolysed rhe slowest in carbon-halogen bonds

A

Fluoroalkanes gave the strongest bonds, so they are the slowest at hydrolysing

326
Q

How can you compare the reactivity of chloroalkanes, bromoalkanes and iodoalkanes

A

1) when you mix a haloalkane with water it reacts to from an alcohol
2) If you put silver nitrate solution in the mixture too, the silver ions react with the halide ions as soon as they from, giving a silver halide precipitate
3) to compare the reactivity set up three test tubes each containing a differnt haloalkane, ethanol and silver nitrate solution ( this contains the water)
4) a pale yellow precipitate quickly forms with 2-iodopropane — so iodoalkanes must be the most reactive haloalkanes, bromoalkanss reacts slows than iododalkes to form a cream precipitate , and chloroalkanes form a white precipitate the slowest of all

327
Q

T or f
CFC are haloalkanes

A

T

328
Q

What are CFCs

A

Chlorofluorocarbons
They contain only chlorine , fluorine and carbon
(All the hydrogens have been replaces)

329
Q

What are the positives Of CFCS

A

stable
Volatile
Non flammable
Non toxic
Low bp
Odourless

330
Q

Why are CFCs so stable

A

Because of the strength of the carbon- hydrogen bonds

331
Q

What does ozone in the upper atmosphere acts as

A

Chemical sunscreen
It absorbs a lot of the ultraviolet racyauion which can cause sunburn or skin cancer

332
Q

How is ozone formed

A

Naturally when an oxygen molecule is broken down into two free radicals by UV radiation. The free radicals attack other oxygen molecules forming ozone

O2 - —- —-> O +O - ——— > o2 + O —— > O3

333
Q

What did scientist discover abiut the ozone layer in 1970z and 1980s

A

Scientists discovered that the ozone layer above Antarctica was getting thinner -
The ozone over the artic has been found to be thinning too.
These holes in the ozone layer allow more harmfull UV radiation to reach earth.

334
Q

How are the holes in the ozone layer formed

A

CFCs in the upper atmosphere absorb UV radiation and split to form chroine free radicals. These free radicals catalyse the destruction of ozone. They destroy ozone molecules and are then regenerated to destroy more ozone. One chlorine atom can destroy 10,000 ozone molecules before it formed a stable compound

Cl. Free facials are catalysts, they react with ozone to from an intermediate (ClO.) and an oxygen molecule

335
Q

What are the 2 propergation reactions for ozone depletion

A

Cl. + O3 —> O2 + Clo3 .
ClO. + O — > O2 + Cl.

(The O radical domes form the break down of oxygen by UV radiation )

336
Q

What is the overall reaction for ozone depletion and what is the catalysts

A

O3 + O —> 2 O2
Cl. Is rhe catalyst

337
Q

NO. Free radicals are form what

A

Nitrogen oxides

338
Q

What do NO. Free radicals destroy

A

Ozone

339
Q

What are nitrogen oxides produced by

A

Car and aircraft engines and thunderstorms

340
Q

NO. Free radicals react. With the ozone the same way as chlorine radicals so the equations can be represent by what

A

R wich represents either Cl. radical or NO. Radical

341
Q

What are the few premitted uses of CfCs

A

Medical inhalers
Fire extinguishers
Submarines

342
Q

What are being used as alternatives to CFCS unrulna a
Safer products are developed

A

HCFCs and HFCs

Hydrocarbons are also used

343
Q

Explain the effect of HCFCs on the ozone

A

They are broken down in the atmosphere in 10-20 years
They still damage rhe ozone later but their effect is much smaller than CFcs

344
Q

Explain the effects of HFCs in the ozone

A

HFCs Are also broken down in the atmosphere. Unlike HCFCs they done contain chlorine , so they don’t affect the ozone layer

345
Q

Negative of HFCs and HCFCs

A

They are greenhouse gasses
They are 1000 times Worse than CO2

346
Q

Negative of hydrocarbons as alternatives to CFCs

A

Greenhouse gases

347
Q

Nowerdays what do most aerosols been replaced by, many industrial fridges and freezers now use what as coolant gas and what is used to make foamed polymers

A

Pump spray systems Or use nitrogen as the propellant
Ammonia
Carbon dioxide

348
Q

Are there still ozone holes

A

Still form in the spring but are slowest shrinking

349
Q

various gasses in the atmosphere that contain what molecules that are able to absorb infrared radiation and re-emit them in all directions
And what is thus called

A

C=O
C-H
O-H

The greenhouse effect

350
Q

What are rhe main greenhouse gases

A

Water vapour
Carbon dioxide
MEthane

351
Q

Over the last 150 years why has there been higher conc of greenhouse gases

A

Worlds pop had increased
We have become more industrialised - meaning we have been burning fossil fuels, releasing Co2 and chopping down forests which absorb CO2
Also growing more food, and cows and paddy fields release lots of methane

352
Q

What does high conc of greenhouse gases mean for the earth

A

More heat being trapped and the earth getting warmer - this is global warming
Global warming is through to be responsible for recent changes to climate - such as the shrinking of the polar ice caps and less predictable weather

353
Q

What evidence is there of climate change

A

Evidence shows that earths average temperature has increased dramatically in the last 50 years and that CO2 levels have increased at the same time. The correlation between CO2 and temperature is pretty clear, but just showing the correlation doesn’t prove that one thing causes another..
There is now a consensus and climate scientist at the link is casual

354
Q

What do climate scientists believe the recent warming is due to

A

Anthropogenic
(Human activities)

355
Q

How are government working to reduce their greenhouse gas emissions

A

Scientific evidence has persuaded governments to form a global agreement that climate change could be damaging for people, the environment and economies and that we should try to limit it

In 1997, the Kyoto protocol was signed- industrialised countries promised to reduce their greenhouse gas emissions to greed levels. The agreement came to an end in 2012 and currently has no replacement though. Many governments agreed that they need to reduce the CO2 emissions by around 50% by 2050.
The UK government has created policies to use more renewable energy supplies, such as wind and solar farms in order to reduce their emissions

356
Q

Describe how an infrared spectroscopy work

A

A beam of IR radiation is passed through a sample of a chemical
The IR radiation is absorbed by the covalent bond in the molecules increasing thru vibrational energy

Bonds between differnt atoms absorb differnt frequency’s of IR radiation.
Bonds in differnt placed in a molecule absorb differnt frequencies

357
Q

What shows as differnt frequencies of IR radiation

A

Bonds between differ atoms
Bonds in differnt places in a molecule

358
Q

Where are C-H groups found

A

Alkyl groups
Alkenes
Adenes

359
Q

Where are O-H groups found

A

Alcohols
Carboxylic acids (but thus has a differnt frequency to alcohols due to the bond being in a differnt place)

360
Q

what does an infrared spectrometer produce

A

A spectrum that shows what frequencies of radiation the molecules are absorbing

361
Q

What can you use the spectrum produced by the infrared spectrometer to identify

A

The functional groups in a molecule
And if a functional group has changed in a reaction

362
Q

Which way do the peaks on IR spectra Point

A

Downwards

363
Q

What is wavenumber

A

Measure used for frequency on an IR spectrum

364
Q

How to calculate wavenumber

A

1/ wavelength in cm

365
Q

Where do most organic compounds produce a peak at and what causes thus

A

About 3000 cm -
C-H

366
Q

What does a strong sharp absorbs ion at 1700 cm-1 show

A

There’s a c=o group

367
Q

What do peaks show on an infrared spectrum

A

Where radiation is being absorbed

368
Q

How are infrared spectroscopy used in brethalysers and why is it chosen

A

To work out if a driver is over the drink - drive limit
The amount of ethanol vapour in the drivers breath is found by measuring the intensity of the peak corresponding to the C-H bond in the IR spectrum.
It’s chosen becasue it’s not affected by any water vapour in the breath

369
Q

Uses of infrared spectroscopy

A

Breathalyser
Monitoring conc of pollution gases (including, CO, NO, which are both present in car Emissionssj

370
Q

How can IR spectroscopy be used to monitor conc of polluting gases

A

The intensity of the leans corresponding to c=- O or N=O can be studied to monitor their levels

371
Q

what can u work out form mass spectrum

A

Relative atomic mass

372
Q

What is a mass spectrum produced by

A

A mass spectrometer

373
Q

How do mass spectrometers work

A

The molecules in a sample are bombarded with electrons which remove an element form the molecule to form a molecular ions, M+(g)

374
Q

How do you find the relative molecular mass for a mass spectrometer

A

Look at the molecular ion peak ( the M peak ) the mass change valve of the molecular ion peak is the molecular mass (this is ash ion the ion has a 1+ change which it normally will)

375
Q

What is on the Y axis is of a mass spectrum

A

Abundance of ins

376
Q

What is on the x axis of a mass spectrum

A

mass/charge ratio

377
Q

For most organic compounds where is the M peak

A

The M peak is rhe one with the second highest mass / change ratio

378
Q

What is the smallest peak to the right of the M peak called

A

The M+1 peak

379
Q

What causes the M+1 peak for organic compounds

A

caused by the presence of the carbon isotope 13C

380
Q

What does the bombarding of the electrons in mass spectrometry make some of the molecular ions beak up into

A

Fragments

381
Q

The fragments that are ions shown up of the mass spectrum making a what pattern

A

Fragmentation

382
Q

What are fragmentation patterns use

A

Use them to identify molecules and their structures

383
Q

T or f
Only ions show up on the mass spectrum, the ………. Are lost

A

T
Free radicals

384
Q

To work out the structural formula from a mass spectrometer , what do you have to work out

A

What ions could have made each peak form it’s m/z value (you assume the m/z value of a peak matches the mass of the ion that made it )

385
Q

Even if two compounds contain the same atoms you can still tell them apart with mass Spectrometry.
Why

A

Because they won’t produce exactly the same set of fragments

386
Q

T or f
Every compound produces a differnt mass spectrum,

A

T

387
Q

What can be used to identify a compound form its spectrum

A

Large computer databases

388
Q

What do you do if you are asked to identify a compound form it’s mass or percentage composition, iR spectrum and mass spectrum

A

1) use the composition to work out the molecular formula of the compound
2) work out what functional groups are in the compound form it’s infrared spectrum
3) use the mass spectrum to work out the structure of the molecule

389
Q

Organic reactions are slow and substances are usually flammable and volatile
What would happen if you heat them with a Bunsen burner

A

Evaporate or catch fire before time to react

390
Q

If you heat an organic with a Bunsen burner they will evaporate and catch fire before you have time to react. how can you get around this problem

A

Reflux reaction

391
Q

What is a reflux reaction

A

Mixture is heated in a flask fitted with a vertical Liebig condenser
- this continuously boils, evaporates and condenses the vapours and recycles them back into thr flask, giving them time to react

392
Q

How is the heating usually done in a reflux reactjon

A

Electrical
Hot plates , heating mantles, or electrical controlled water baths

393
Q

Why are heating usually done electrically for refluxing

A

To avoid naked flames that might ignite compounds

394
Q

Why are anti-bumping granules added for refluxing

A

Added to make boiling smoother

395
Q

How does distillation work

A

By gently heating a mixture in a distillation apparatus
The substances will evaporate out of the mixture in order to increase boiling points

396
Q

What does the thermometer show when doing distillation

A

Shows the boiling points of the substances that is evaporating at any given time

397
Q

If you known the boiling point of your pure product, what can you use when doing distillation to tell you when it’s evaporating and therevpfore………….

A

Thermometer
Condensing

398
Q

If the product of a reaction has a lower boiling point than the starting material.
Then what can you do

A

The reaction mixture can be heated so that the product evaporates form the reaction mixture as it forms

399
Q

If the starting material of distillation has a higher boiling point than the product.
So long as what is controlled it won’t evaporate out of the reaction mixture

A

Temperature

400
Q

T or f
Sometimes a product is formed that will go on to react further if it is left in the reaction mixture

A

T

401
Q

What can redistillation be used for

A

If products and irs impurities have differnt boiling points , then redistillation can be used to separate them,

402
Q

How do you carry out redistillation

A

Use the same distillation apparatus, but this time your heating and impure product instead of reaction mixture when the liquid you want boils you place a flask at the open end of the condenser ready to collect your product when thermometer shows the temperature is changing put another flask at the end of the condenser because a different liquid is about to be delivered

403
Q

If the products is insoluble in water, what can you use separation to remove

A

Any impurities that do dissolve in water, such as salts or water soluble organic compounds

404
Q

Describe separation

A

Reaction complete
The mixture is poured into a separating funnel and water is added
The funnel is shaken and then allowed settle. The organic later is less dense than the aqueous layer so should float on top. Any water soluble impurities should have dissolved in the lower aqueous layer. You can them open the stopped on the separating funnel and run of the aqueous layer and collect your product

405
Q

If you use separation to purify a product, the organic layer will end up with trace amounts of what, so what does it have to be …

A

Water
Dried

406
Q

How can you dry an organic layer that has been left after separation

A

Add anhydrous salt such as magnesium sulfate or calcium chloride. The salt is used as a drying agent - it binds to any water present to become hydrated

When you first ass the salt to the organic layer it will be lumpy. This means you need to add more. You know that all the water has been removed when you swirl the mixturre and it looks like a snow globe

You can filter the mixture to remove the solid drying agent

407
Q

What does a synthetic route show

A

How to get from one compound to another
It shows all the reactions with the intermediate products and the reagents needed for each reaction

408
Q

If you heat a primary alchcok with what reagents under reflect it goes straight to a carboxylic acid

A

K2Cr2O7
H2SO4
Heat secondary alcohol in reflux apparatus

409
Q

Conditions for haloalkane to alchcol

A

Warm NaOH or KOH, H2O reflux

410
Q

Haloalkane to Alcochol
What can you use to test the C-X bond strengths

A

H2o
AGNO3

411
Q

Conditions alcohol to haloalkane

A

NaX
H2SO4
20°C

412
Q

Conditions for alcohol to aldehyde

A

K2Cr2O7
H2SO4
Heat primary alcohol in distillation apparatus

413
Q

Conditions for aldehyde to carboxylic acid

A

K2Cr2O7
H2SO4
Reflux

414
Q

Alcohol to ketone conditions

A

K2Cr2O7
H2SO4
Heat secondary alcohol in reflux apparatus

415
Q

Alcohol to alkene conditions

A

Conc. H2SO4 or H3PO4, hear

416
Q

Alkene to alcohol Condirions

A

Steam,
H2SO4 or H3PO4 catalyst,
300°C
60-70 atm

417
Q

Alkene to Dihaloakene conditions

A

X2
20°C

418
Q

Alkene to dihaloalanez
What do you add as X2 to test for in saturation

A

Br2

419
Q

Alkene to haloalkane conditions

A

HX
20°c

420
Q

Alkene to alkane conditions

A

H2
Nickel catalyst
150°c

421
Q

Alkane functional group

A

C-C

422
Q

Properties of alkane

A

Non polar
Unreactive

423
Q

What typical reaction for alkanes undergo

A

Radical susbstitution

424
Q

Alkene to functional group

A

C=C

425
Q

Alkene properties

A

Non polar
Electron rich double bond

426
Q

Typical reactions for alkenes

A

Electrophilic addition

427
Q

Functional group of alcohols

A

C-OH

428
Q

Properties of alcohols

A

Polar C-OH bond
Lone pair on O can act as a nucleophile

429
Q

Typical reactions of alcohols

A

Nucleophilic substitution
Dehydration / elimination

430
Q

Functional group of haloalkane

A

C-X

431
Q

Properties of haloalanes

A

Polar C-X bond

432
Q

Typical reactions of halo alkenes

A

Nucleophilic substitution

433
Q

Aldehyde / ketone functional group C=O

A
434
Q

Properties of aldehyde / ketone

A

Polar C=O bond

435
Q

Typical reactions of aldehyde / ketones

A

Aldehydes will oxidise

436
Q

Carboxylic acid functional group

A

-COOH

437
Q

Properties of Carboxylic acid

A

Electron deficient carbon centre

438
Q

Typical reactions of carboxylic acid

A

Esterification

439
Q

Can a compound have more than one functional group

A

Yes

440
Q

What should you include if you are asked how to make one compound for another in an exam

A

1) any special procedures such as refluxing
2) conditions needed

441
Q

Bonding in alkenes

A

No rotation in alkenes around double bond because 2 P-orbitals overlap sideways ( pi bonds)

442
Q

Describe a pi bond

A

Very electron dense

443
Q

In alkenes each carbon only bonded to 3 other atoms
What does thus cause

A

2p2 hybridisation

Causes a very negative region of space above and below the plane of the polecule

444
Q

Why is pi bond weaker than sigma

A

Very negative region of space above and below plane of molecules
Distant from control of nuclei

445
Q

Physical alkene properties

A

Each alekene has 2 fewer e- than the corresponding alkane - so similar but alkenes is slightly lower London forces

Mp / bp inc, with nu, of carbon atoms as the strength of London forces increases

Insoluble in water

446
Q

Why type of reaction turns alkenes in haloalames

A

Electrophilic addirion reactions

447
Q

What does electrophillic mean ( basic )

A

Electron loving

448
Q

What are polymers

A

Large molecules built up from small repeating units called monomers

449
Q

How do polymer come about

A

Naturally in living things and through chemical processes in industry

450
Q

What’s the minimum amount of carbons a monomer should have

A

At least 2 carbons

451
Q

What does the n mean on a polymer

A

Number of repeated units

452
Q

What types of chemical bonding is polymers

A

Covalent

453
Q

Uses of poly (ethene)

A

Most commonly used polymer
Eg, shampoo bottles

454
Q

Uses of poly(chloroethene)

A

Pipes

455
Q

Uses of poly(propane)

A

Toys
Packing creates

456
Q

Uses of poly(phenylethene)

A

Packing material
Food trays

457
Q

Uses of poly ( tetrafluoroethene)

A

Coating for non stick pans
Cable insulation

458
Q

Addition polymers are formed from alkene
What is this called

A

additition polymerisation

459
Q

Why are poly(alkenes) unreactive

A

Strong C-C and C-H bonds

460
Q

What is the manufacturing process for margarine

A

Catalytic hydrogenation of unsaturated vegetable oils using hydrogen and nickel catalyst

Liquid vegetable oils are generally polyunsaturated alkenes. Hydrdogenation by reaction of hydrogen using a nickle catalyst converts the double bond to saturated single bonds. Thus increases the melting poking og the oils making it harder and more solid

461
Q

What does hydration of alkenes mean

A

Adding water

462
Q

What is hydration of alkenes a way of marking

A

Alcohols

463
Q

What conditions is needed in hydration of alkenes

A

acid catalyst
Eg, sulphuric acid

464
Q

What does dehydration of alcohols form by removing what

A

Alkenes
Removing OH

465
Q

In dehydration is the less substituted or more substituted alkene more likely to form

A

More substituted

466
Q

Do the trans alkenes or cis alkenes form more
So what is it called
(Usually)

A

Trans
so major
The cis is minor

467
Q

Are addition polymers polar

A

No they are non polar

468
Q

What problems does addition polymers and inert cause

A

Creates potential environmental problems during disposal

469
Q

What 2 ways can you dispose addition polymers

A

Landfill
Burning

470
Q

Issues with landfill of addition polymers

A

Long term problems
Non biodegradable so takes many years to break down

471
Q

Issues with burning addition polymers

A

Produce toxic fumes

472
Q

are condensation polymers polar

A

Yes

473
Q

How are condensation polymers broken down

A

Naturally by hydrolysis into their monomer units
Therfore biodegradable and easier to dispose of

474
Q

What are bioplastics made of

A

wholly or in part from renewable biomass sources such as sugarcane and corn, or from microbes such as yeast.

475
Q

Bioplastics made from renewable resources can be …….

A

be naturally recycled by biological processes, thus limiting the use of fossil fuels and protecting the environment. Therefore, bioplastics are sustainable, largely biodegradable, and biocompatible

476
Q

Uses of bio plastics

A

Food packaging, agriculture, compositing bags, hygiene, biomedical products, structural products. Ect

477
Q

What does biodegradable or compostable mean

A

can be broken down by microorganisms into water, carbon dioxide, mineral salts and new biomass within a defined period of time.

478
Q

How quickly something biodegrades depends on what

A

conditions it’s exposed to
Including temp, duration, presence of microorganisms, nutrients, oxygen and moisture

479
Q

What a Photodegradable polymers designed to do

A

degrade when exposed to sunlight in the environment

480
Q

Uses of Photodegradable polymers

A

• Plastic waste disposal problems
• Photodegradation of plastic contamination in the marine environment
• Production of photodegradable mulch films with carefully controlled lifetimes.

481
Q

what 2 steps help products biodegrade

A

Oxidation
Biodegrading

482
Q

What 2 ways are there to make plastics photodegradable

A

Chemists can add a substance that absorbs sunlight to the plastic. The sunlight makes this substance more reactive and it attacks the polymer chains the plastic is made from. When a ‘package’ of light (a photon) hits a molecule of the added substance this molecule helps focus the energy of the sunlight in a way which causes some of the bonds in the polymer to break. The chains become fractured and brittle so the plastic falls apart.

483
Q

Micro-organisms can attack polythene but only slowly and not if the polythene has a molecular weight greater than about …….

A

500

484
Q

Once photodegradable plastic is exposed to light it begins to break down – whether you want it to or not. This can be disastrous if it is mixed with other plastics during recycling.’ Why would this be a disaster?

A

Photodegradable plastics tend to breakdown in smaller pieces than the smaller pieces will buy the grade if mix, they will most likely be buried in landfill. It is too dark to do this degrading process.

485
Q

What does solubility mean

A

A measure of how able a compound dissolves in a given solvent

486
Q

Why are alcohols soluble in polar solvent s

A

polar itself
Energy released from new H bonds formed compensate for the energy required to overcome the origional H bonds

487
Q

Why are longer alcohols less soluble

A

Most of chain is non polar
So can’t for H bonds
Energetically unfavourable to form new H bonds

488
Q

What is a dichromate ion

A

Cr2O7. ^2-

489
Q

What is the colour change that dichromate ion undergoes when it is reduced

A

Orange to green

490
Q

How can you distinguish between an Carboxylic acid and an aldehyde

A

Add sodium carbonate
Fizzing indicated Carboxylic acid

491
Q

How do u get from an alcohol to an Carboxylic acid

A

excess oxidising agent

492
Q

Primary alcohols oxidation to aldehyde conditions

A

Dilute H2SO4
K2Cr2O7
Distill

493
Q

Primary alcohols to Carboxylic acid conditions

A

Excess K2Cr2O7
Heat under reflux
Dilute H2SO4

494
Q

Conditions for secondary alcohols to ketone

A

Dilute H2SO4
K2Cr2O7
Reflux

495
Q

What is the order of reactivity of alcohols

A

3°>2°>1°

496
Q

What is the general equation for halogenation of a tertiary alcohol

A

R-OH + HX —> R-X + H2O

497
Q

What type of reaction is halogens and alcohols

A

Nucelophilic substitution

498
Q

Why is an acid needed for halogenation of alcohols

A

Because Oh is a poor leaving group
And O+H2 is a great leaving group

499
Q

General equation for a secondary and primary alcohol

A

R-OH + NaX _______H2SO4______> R-X + NaHSO4 + H2O

500
Q

What is the differnce between the curly arrow mechanism of secondary/ primary and tertiary

A

Primary and secondary won’t form a carbocation as not stable enough.
Tertiary needs to form a carbocation as otherwise not enough room for substitution

501
Q

What are the polarity of haloalkanes

A

Haloalkanes contain a C-X bond
The C-X bond is polar
As hallogens are more electron ene fatigue than carbon
Electronegativity decreases down group 7

502
Q

What is the solubityly of haloalkanes in water

A

The bond is not polar enough to dissolve in water

503
Q

Haloalkes do mix with
………… easily so can be used to clean out stains

A

Hydrocarbons

504
Q

Do haloalkanes tend to dissolve in organic solvents, why/why not

A

Yes
Beacuse the new IMFS have the same strength as the ones being broken in the separate haloalkanes and solvent

505
Q

Why can haloalkanes undergo nucleophilic substitution

A

Due to the polarity
So the Bond is attacked by nucleophilws

506
Q

Examples of nucleophiles

A

OH-
H2O
NH3
CN

507
Q

What type of haloalkanes can undergo nucleophilic substitution recation

A

Primary

508
Q

What is the strongest
c- halogen bond
And why

A

C-F
Because F is the smallest halogen and so the sharing of electrons are strongly attracted to the F nucleus

509
Q

Which C-halogen bond is the most reactive

A

Iodine

510
Q

In organic mass spectrum the highest m/z value usually corresponds to?

A

the molecular ion
And its position provided info on the molecular mass

511
Q

What are the peaks on mass spectrum from

A

Fragments

512
Q

Why do many fragments not show up on on mass spectrum of organic molecules

A

They are not charged ions

513
Q

What is the M+1 peak in mass spectrometry of carbon due to ?

A

Natural abundance of carbon -13

514
Q

In mass spectrum
the abundance is effected by what
Explain in detail

A

The stability of the carbocation
The more stable the higher the peaks
The more alkyl groups attached to the carbonation the more stable it is

515
Q

Why does the mass spectrum of haloalkane oftern show multiple peaks in the molecular ion region

A

Due to the differnt isotopes of the halogens

516
Q

What is a common fragment of aldehydes and ketones

A

Carbon monoxide

517
Q

Why won’t carbon monoxide fragment not show up on mass spectrum
- but what will it produce

A

It’s a molecule so uncharged
It will produce a m/z drop of 28 somewhere in the spectrum

518
Q

Why does the position of the carbonyl group influence the fragmentation pattern

A

The molecular ion fragments either side of the carbon group
The more stable the acylium ion RCO+ the more abundant it will be
The more abundant the species the taller it’s peak

519
Q

What can you use mass spectrometry of organic compounds for

A

Identify molar mass of organic compounds
Gain information about structure

520
Q

Describe the mass spectrum

A

Sample vaporised, ionised to form positive ions
Ions accelerated, heavier move slower
Ions detected as mass:charge ratio m/z
As ions reach detector they create a signal which is detected so the greater the abundance the larger the signal

521
Q

What forms peaks on mass spectrum of organic moelcuels

A

Fragments of molecules

522
Q

What is rhe M+ peak formed by in a mass spectrum of organic moelcuels

A

Ion of the whole molecule

523
Q

Where do problems with M+ peaks occur on mass spectrum of organic molecules

A

Problems when elements have a high rate of isotopes
Eg, cl and br
This produce a M+ and an M+2 peak

524
Q

What peak can carbon-13 produce on a mass spectrum

A

M+1 peak

525
Q

What does the amount a bond stretch or bend depend on

A

Mass of atom and strength of bond
( lighter and stronger bonds is faster

526
Q

Each chemical bond has a unique natural frequency caused by …..

A

Vibration in bond

527
Q

The bonds absorb energy from wavelength of radiation that has ……

A

The same frequency

528
Q

On IR - low intensity means that compound has……

A

Absorbed that frequency

529
Q

What is the fingerprint region

A

Below 1500cm-1
It’s unique to every compound
- it’s more difficult to pick out individual bonds

530
Q

Describe what a carbonyl compound will look like on infrared spectrum,

A

Sharp and strong absorption around 1700cm-1
Due to c=o bond

531
Q

Describe what an alcohol will look like on an IR spectrum

A

Between 3200 and 3600cm-1
Due to O-H bond
Also peak between 1000 and 1300 due to c-o bond

532
Q

Descirbe what a Carboxylic acid would look like on an IR spectrum

A

B-road absorption Bayern 2500 and 3300 cm-1
Due to O-H bond
Also strong absoptiom at 1700cm-1 due to C=O bond
Also peak between 1000 and 1300 due to c-o bond

533
Q

De#curb the infrared spectrophotometer

A

A beam if infra red radiation passes through sample
A similar beam is passed through the reference cell
The frequency of radiation is varied.
Bond vibrating with a similar frequency absorbs radiation
The amount of radiation absorbed by the sample is compared with the reference

534
Q

UV absorbed
- what is rhe energy used fro
- and what spectroscopy technique

A

Movement of electron to higher energy levels
Uv spectroscopy

535
Q

Infra red absorbed

what is rhe energy used fro
- and what spectroscopy technique

A

To vibrate bonds
Infra red spectroscopy

536
Q

Microwaves absorbed

what is rhe energy used fro
- and what spectroscopy technique

A

To rotate molecules
Microwave spectroscopy

537
Q

Radio waves absorbed
what is rhe energy used fro
- and what spectroscopy technique

A

To change nuclear spin
NMR spectroscopy

538
Q

What are the 3 differnt types of vibrations

A

Symmetrical stretch
Asymmetrical stretch
Bending

539
Q

If IR light is passed through the compound
What will is absorb

A

Some or all of the light at the frequencies at which it’s bonds vibrate

540
Q

What are wave numbers

A

Used as a measure of the wavelength of frequency of the absorbtion

541
Q

What range is IR light absorbed

A

4000-400

542
Q

What can the fingerprint region also be checked to see

A

If a compound is pure

A-level Chemistry <3 (9 decks)

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