Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

NSFC Chemistry AQA A level Y13 > Organic Model Answers > Flashcards

Organic Model Answers Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Chemistry flashcards Periodic Table flashcards Chemistry 101 flashcards Organic Chemistry 101 flashcards
1
Q

What’s empirical formula?

A

The simplest whole number ratio of atoms in a compound

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What’s molecular formula?

A

The actual whole number ratio of atoms in a compound

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What’s general formula? What’s the general formula for alkanes and alkenes?

A

The formula to show the number of each atoms in a homologous series.
Alkanes CnH2n+2
Alkenes CnH2n

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What’s structural formula?

A

A formula that shows the connectivity in an organic molecule without showing bonds (eg ethane is CH3CH3)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What’s displayed formula?

A

A formula that shows all the bonds in an organic molecule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What’s skeletal formula?

A

Shows all the bonds in a compound where all the vertices are carbon with their full compliment of hydrogens (a single line is still a covalent bond).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What’s a homologous series?

A

A group of compounds with the exact same functional groups and the same general formula.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the general rules for naming carbon chains using IUPAC nomenclature?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Homologous series - What do they have in common?

A

They show a gradual change in physical properties (e.g. boiling point).
Each member differs by CH2 from the last.
same chemical properties.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What’s the infix of a carbon chain with 1 carbon?

A

Meth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What’s the infix of a carbon chain with 2 carbon?

A

Eth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What’s the infix of a carbon chain with 3 carbon?

A

Prop

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What’s the infix of a carbon chain with 4 carbon?

A

But

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What’s the infix of a carbon chain with 5 carbon?

A

Pent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What’s the infix of a carbon chain with 6 carbon?

A

Hex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the basic rules for naming functional groups?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How do you name amines?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How do you name nitriles?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How do you name esters?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How do you name acid anhydrides?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How do you name acyl chlorides?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How do you name amides?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How do you name aromatic compounds?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Define Structural isomerism

A

Compounds have the same molecular formula but a different structure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Define functional group isomer

A

Compound with the same molecular formula but a different functional group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Define position isomer

A

Compound with the same molecular formula but a different position of the functional group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Define chain isomer

A

Compound with the same molecular formula but a different length longest carbon chain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Define stereoisomer

A

Compound with the same structural formula but a different arrangement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Define geometric isomer

A

Compound with the same structural formula but a different arrangement around a non-rotational carbon-carbon double bond

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Define optical isomer

A

A compound with the same structural formula but a different arrangement around a chiral carbon (or with a different non- superimposable image)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What are the CIP rules?

A

The Cahn-Ingold-Prelog priority rules are:

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What causes E/Z isomerism?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What does saturated and unsaturated mean?

A

A saturated organic compound has all single bonds,

Unsaturated organic compounds have at least one double bond

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Define hydrocarbon

A

A compound made of carbon and hydrogen only.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Define petroleum

A

Petroleum is a mixture consisting mainly of alkane hydrocarbons that can be separated by fractional distillation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

How does fractional distillation work?

A

Separates different fractions based on their boiling points. The longer carbon chain fractions have stronger van der Waal’s forces between molecules so will condense lower down the fractionating column due to the temperature gradient in the fractionating column (from hotter to colder).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What are the trends in viscosity, volatility and flammability of the alkane homologous series? Why?

A

Viscosity increases with chain length as the molecules increase in size there is stronger van der Waal’s forces between molecules. Volatility decreases for the same reason.

Flammability decreases with carbon chain length as there are fewer of the molecules evaporated in the air nearby, making vapours harder to react.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What is cracking? Why is cracking done?

A

Breaking the C-C bonds in alkanes to make smaller chain alkanes from longer chain alkanes.

It’s done to turn lower in demand hydrocarbons into more in demand hydrocarbons.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What’s thermal cracking? What are the conditions? Why is it used?

A

Thermal cracking takes place at high pressure and high temperature and produces a high percentage of alkenes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What’s catalytic cracking? What are the conditions? Why is it used?

A

Catalytic cracking takes place at a slight pressure, high temperature and in the presence of a zeolite catalyst and is used mainly to produce motor fuels and aromatic hydrocarbons.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What are the two types of combustion and why do both occur? What are the common products of each case when combusting hydrocarbons?

A

Complete combustion - when oxygen is in excess, products are CO2 and H2O
Incomplete combustion - when oxygen isn’t in excess, products can be CO or C and H2O.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What pollutants are produced from the internal combustion engine. What problems can they cause?

A

NOx, - toxic
CO, - toxic, can bind to hamoglobin more strongly,
carbon - can cause respiratory hazards
unburned hydrocarbons, - methane is a greenhouse gas
SO2 if sulfur impurities present, can produce acid rain (H2SO3) if they react with H2O
H2O - green house gas,
CO2 - green house gas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

How can NOx, CO, carbon and unburned hydrocarbons be removed?

A

Using a platinum catalytic converter that removes the impurities

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

How can sulfur dioxide be removed from flue gases?

A

By using calcium oxide/carbonate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

When is the reaction nucleophilic substitution or elimination?

A

OH- must be the reacting chemical,
If it’s OH- in the reaction, then hot alcoholic conditions are needed to cause OH- to act as a base in an elimination mechanism.
If it’s warm and aqueous conditions then OH- acts as a nucleophile

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

What is ozone? Why is it important for life on Earth?

A

O3,
Ozone, formed naturally in the upper atmosphere, is beneficial because it absorbs ultraviolet radiation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What are CFCs? What do CFCs do to ozone?

A

Chlorine atoms are formed in the upper atmosphere when ultraviolet radiation causes C–Cl bonds in chlorofluorocarbons (CFCs) to break.

Chlorine atoms catalyse the decomposition of ozone and contribute to the hole in the ozone layer.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

What are the equations to show the propagation step of the degradation of ozone?

A

Cl* + O3 → ClO* + O2
ClO* + O3 → 2O2 + Cl*

  • should be a dot
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Why do we no longer use CFCs? What do we use instead?

A

Different groups in the scientific community provided evidence for legislation to ban the use of CFCs as solvents and refrigerants. Chemists have now developed alternative chlorine-free compounds.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

What’s the key feature of an alkene?

A

a C=C bond

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

What’s the chemical test and observation for alkenes?

A

Add bromine water,
Observation is orange to colourless

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

What causes major and minor products when reacting alkenes? Why?

A

Tertiary carbocations are more stable than secondary carbocations.
Secondary carbocations are more stable than primary carbocations.
This is due to more carbon chains leading to a stronger positive inductive effect, when electron density is pushed onto the C+ from the alkyl chains surrounding it. More alkyl chains means a more stable carbocation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

What’s an addition polymer? How are they formed?

A

Addition polymers are alkene monomers all joined together breaking a double bond in each to create a poly(alkene).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

What’s a monomer?

A

A compound that will become part of a polymer.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

What’s a polymer?

A

A large molecule joined up of monomers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

Using propene as an example what should the equation for the formation of a poly(alkene) look like?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

What’s a repeating unit look like?

A

Show the trailing bonds on the outside of monomers and at least one of all monomers involved.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

What’s the structure of poly(chloroethene)?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

What’s a plasticiser?

A

A plasticiser is a compound that sits between polymer chains, increasing the distance between them. This causes the intermolecular forces between the molecules to weaken, making the compound more flexible.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

Why aren’t poly(alkenes) biodegradable?

A

They’re long polymer chains with many strong non-polar C-C bonds.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

How can alcohols be produced?

A

Alcohols are produced industrially by hydration of alkenes in the presence of an acid catalyst.

Ethanol is produced industrially by fermentation of glucose. The conditions for this process

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

What happens in the hydration of alkenes? What are the advantages and disadvantages?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

What happens in fermentation? What are the advantages and disadvantages?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

What’s the mechanism for the hydration of ethene?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

How is ethanol turned into a biofuel?

A

Ethanol produced industrially by fermentation is separated by fractional distillation and can then be used as a biofuel.

66
Q

Define biofuel

A

A fuel derived immediately from organic matter

67
Q

What are the three different types of alcohols? [Use propanol based compounds as an example]

A
68
Q

How do the different types of alcohols react with acidified potassium dichromate?

A

Primary alcohols can be oxidised to aldehydes which can be further oxidised to carboxylic acids.

Secondary alcohols can be oxidised to ketones.

Tertiary alcohols are not easily oxidised.

69
Q

What will happen if acidified potassium dichromate is refluxed with a secondary alcohol?

A

The alcohol will become a ketone

70
Q

What will happen if acidified potassium dichromate is refluxed with a primary alcohol?

A

The alcohol will become a carboxylic acid

71
Q

What will happen if acidified potassium dichromate is distilled with a primary alcohol?

A

The alcohol will become an aldehyde

72
Q

Name an oxidising agent for alcohols,

A

Acidified potassium dichromate,

Sulfuric acid is the preferred acid for this

73
Q

How do aldehydes appear in structural formula?

A
74
Q

How should distillation apparatus be set up? Why?

A
75
Q

How should reflux equipment be set up? How should they be drawn?

A
76
Q

What’s the colour change for addition of acidified potassium dichromate? What does it react with?

A

Primary and secondary alcohols and aldehydes,
Orange to green

77
Q

How do you show an equation for the oxidation of an alcohol?

A

Add in [O] as a reagent and then write in the formula of a product, H2O is made too.

78
Q

How can poly(alkenes) be made sustainably?

A

By fermentation to produce an alcohol and then using acid catalysed elimination to produce an alkene.

79
Q

How are polymers named

A

poly(name of the monomer including the ene)

80
Q

What’s the test for an aldehyde?

A

Tollens reagent - observation silver mirror

81
Q

What’s the test for an aldehyde?

A

Fehling’s solution - observation blue solution to brick red precipitate

82
Q

What’s the test for a carboxylic acid?

A

Add NaHCO3 - observation is effervesence

83
Q

How can you use IR to identify compounds

A

Compare the fingerprint region (1500 cm-1 and below) to a database of known compounds

84
Q

How do you find Mr of a compound from mass spec?

A

If electrospray used than the Mr = the m/z molecular ion peak -1
If electron bombardment used then the Mr = m/z of molecular ion peak

85
Q

What’s the test for optical isomers?

A

Each enantiomer rotates plane polarised light in equal and opposite directions

86
Q

Define enantiomer

A

one of the 2 different optical isomers with the same molecular fomrula

87
Q

Define racemate/racemic mixture

A

A 50:50 mix of each of the enantiomers of that compound

88
Q

How can exhibit optical isomers without being optically active?

A

When a racemic mixture is formed so the plane polarised light is rotated in equal and opposite directions.

89
Q

What do aldehydes and asymmetric ketones form when being reacted with KCN? What type of isomerism is there? Why?

A

Hydroxy Nitriles - As the carbonyl is planar there is an equal chance of either enantiomer forming so a racemate forms. No optical activity is seen.

90
Q

What condition does KCN need when being used as a reagent?

A

Aqueous ethanolic conditions

91
Q

How do you name compounds with alcohol groups and nitriles?

A

hydroxy _name of chain length nitrile (reminder the nitrile is the triple bond N the C needs to be include in the longest chain)

92
Q

What reagent is needed to reduce aldehydes/ketones?

A

NaBH4

93
Q

How are hydroxy nitriles formed? Why?

A

KCN and then add in an acid (sulfuric)

This is because while KCN is corrosive and toxic HCN is even more dangerous and harmful to humans and needs to be avoided in being made in the process.

94
Q

How are esters named?

A
95
Q

How are esters synthesised?

A

Carboxylic acids react with alcohols, in the presence of a strong acid catalyst, to form esters and water. This is a condensation reaction, sometimes called esterification. The reaction is in equilibrium.

96
Q

How are esters used?

A

Esters are sweet smelling compounds that can be used in perfumes and flavourings.
Esters can be used as solvents for polar organic substances.
Esters can be used as plasticisers for polymers.

97
Q

What’s the test for alcohols?

A

Add acidified potassium dichromate - observation orange to green (only works for primary and secondary alcohols and aldehydes)

98
Q

What’s a test for all alcohols

A

Add ethanoic acid and a few drops of sulfuric acid get a sweet fruity smell as an ester is formed

99
Q

Ester hydrolysis - what happens in it? What can be formed?

A

Esters can be hydrolysed and split up by either heating with strong acid (eg sulfuric acid) or with sodium hydroxide.

If sodium hydroxide is added sodium carboxylates and alcohols are produced.
If a strong acid is added then an alcohol and a carboxylic acid are produced.

100
Q

What’s saponification? How do soaps work Give an generic equation to show saponification of animal fats/vegetable oils.

A

Making a soap by creating micelles where the ionic part of the molecule faces

101
Q

What are fatty acids and vegetable oils?

A

Fats and oils are esters of glycerol and long chain carboxylic acids (fatty acids)

102
Q

How can soap be produced?

A

Vegetable oils and animal fats can be hydrolysed to give soap, glycerol and long chain carboxylic (fatty) acids

103
Q

What’s a biodiesel?

A

Biodiesel is a mixture of methyl esters of long chain carboxylic acids

104
Q

What’s the general equation for making biodiesel? What reagent is always used?

A

Methanol

105
Q

Describe the bonding of benzene

A

Benzene is a 6 membered ring where each C has three covalent bonds, 2 to other C and one to a H. Spare electrons in a p orbital overlap to form adelocalized πsystem

106
Q

Describe the structure of benzene

A

Benzene is a planar hexagon with all bonds the same length and all bond angles the same angle (120 degrees).

107
Q

What evidence is there that benzene is not an alkene?

A

bromine water does not decolourise when added to benzene and other aromatic compounds

108
Q

What evidence is there that benzene is more stable than expected based on hydrogenation enthalpies?

A

Expected ∆Hhydrogenation of cyclohexatriene = –360 kJ mol–1
∆Hhydrogenation benzene (is less exothermic) by 152 kJ mol–1
Benzene lower in energy than cyclohexatriene / Benzene is more stable

109
Q

What causes aromaticity?

A

Alternating double and single bonds so many compounds can be more stable than expected, not just benzene, due to this aromaticity

110
Q

Describe the length of an aromatic bond

A

bond length intermediate between single and double.

111
Q

How can amines be prepared from a halogenoalkane of the same chain length? What are the drawbacks of this? What reagent and conditions are needed

A

Nucleophilic substitution of with NH3

Drawbacks as the amine is produced it can continue to react the the halogenoalkanes so more substituted amines will be produced which lowers the yield.

To combat this an excess of ammonia should be used, but this won’t fix the issue.

112
Q

How can amines be prepared from a halogenoalkane with one fewer carbons? What reagents and conditions are needed? what’s the benefit of this?

A

Add KCN and then after the halogenoalkane has completely reacted reduce these to form the desired amine.

1) Use aqueous alcoholic KCN
2) Hydrogen with a Nickel catalyst

benefit - make one pure amine so yield is higher.

113
Q

What are aromatic amines used for?

A

are used in the manufacture of dyes.

114
Q

What’s the trend in base properties of amines? What’s the reason for this?

A

The more alkyl chains the stronger the positive inductive effect so lone pair is pushed further away from the N in the amine. This makes the N’s lone pair more available to accept H+.

Aromatic<NH3<Primary<Secondary<Tertiary

115
Q

What are the types of amine?

A

Tertiary - N with 3 alkyl chains,
Secondary - NH with 2 alkyl chains,
Primary - NH2 with 1 alkyl chains

116
Q

What is a quaternary ammonium salt? How are they formed? How are they used?

A

Quaternary ammonium salts are a N with 4 alkyl chains attached to them. They’re formed when an excess of a halogenoalkane is reacted with ammonia.

Quaternary ammonium salts are used a cationic surfacants like fabric softener.

117
Q

What are condensation polymers? How are they made?

A

Condensation polymers are polymers formed from condensation reactions (the removal of water).

They can be formed from: dicarboxylic acids and diols,
dicarboxylic acids and diamines, or amino acids.

118
Q

How are polymers drawn?

A

In square brackets with trailing bonds outside and an n to denote the number of those monomers

119
Q

What’s terylene? How’s it made? What’s it used for?

A
120
Q

What’s 6,6 nylon? How’s it made? What’s it used for?

A
121
Q

What’s kevlar? How’s it made? What’s it used for?

A
122
Q

How can condensation polymers be damaged?

A

They can be hydrolysed where water is added (with a strong acid or base catalyst).

123
Q

What are the problems with the disposal of polymers?

A

Landfill
The most common method of disposal of waste in UK Many are now reaching capacity. European regulations will mean councils are charged much more for using landfill. Most polymers (polyalkenes) are non-biodegradable and take many years to break down. Could use more biodegradable plastics, e.g. Polyamides and cellulose and starch based polymers to improve rates of decomposition.
Incineration
Rubbish is burnt and energy produced is used to generate electricity. Some toxins can be released on incineration. Modern incinerators can burn more efficiently and most toxins and pollutants can be removed. Greenhouse gases will still be emitted though. Volume of rubbish is greatly reduced.
Recycling
Saves raw materials- nearly all polymers are formed from compounds sourced/produced from crude oil. Saves precious resources. Polymers need collecting/ sorting- expensive process in terms of energy and manpower. Polymers can only be recycled into the same type– so careful separation needs to be done. Thermoplastic polymers can be melted down and reshaped.

124
Q

Why are condensation polymers biodegradable?

A

They have polar bonds and so can be attacked by nucleophiles and broken down.

They can be hydrolysed.

125
Q

What is a zwitterion?

A

When an amino acid’s NH2 and COOH group become NH3+ and COO- making an ionic compound.

The R group doesn’t change.

126
Q

What’s an amino acid?

A

A compound that contains a neighbouring CHNH2 and COOH with an R group on the same C as NH2.

127
Q

What happens when an amino acid is placed in a high pH solution?

A

The COOH becomes COO-

128
Q

What happens when an amino acids is placed in a low pH solution?

A

The NH2 becomes NH3+

129
Q

What is a protein?

A

Proteins are sequences of amino acids joined by peptide links.

130
Q

Describe the primary structure of a protein

A
131
Q

Describe the secondary structure of a protein

A
132
Q

Describe the tertiary structure of a protein

A

Order of strength of attraction:
Strongest:
Disulfide bridges (because they’re covalent bonds)
Ionic bonds (between NH3+ and COO-)
Hydrogen bonds between amino acids
van der waal’s forces between amino acids
Weakest

133
Q

How do amino acids join together? Give a generic example

A

Condensation reaction

134
Q

What do you call a group of amino acids condensed together?

A

A dipeptide (2 amino acids)
A tripeptide (3 amino acids)
Polypeptide (many amino acids)

135
Q

How can amino acids be made to appear on TLC plates and identified?

A

Amino acids can be located on a chromatogram using developing agents such as ninhydrin or ultraviolet light and identified by their Rf values.

136
Q

What type of molecule is an enzyme?

A

A protein

137
Q

What do enzymes do?

A

They act as catalysts with a stereoselective active site that binds to a substrate molecule.

138
Q

How can enzymes be controlled?

A

Drugs can be developed that inhibit them by designing molecules on computers that are optically active and block the active site.

139
Q

Why can enzymes only bind to one enatiomer of a substrate/drug?

A

Because of the enzyme’s stereospecific active site

140
Q

What’s a nucleotide made up of?

A

A phosphate on carbon 5 of the deoxy ribose and a base on carbon 1 of the deoxy ribose sugar (structures on the data sheet).

141
Q

Which H on the DNA bases is removed during condensation onto the deoxyribose sugar?

A

Highlighted in blue

142
Q

Describe the structure of DNA

A

A single strand of DNA (deoxyribonucleic acid) is a polymer of nucleotides linked by covalent bonds between the phosphate group of one nucleotide and the 2-deoxyribose of another nucleotide. This results in a sugar-phosphate-sugar-phosphate polymer chain with bases attached to the sugars in the chain.

DNA exists as two complementary strands arranged in the form of a double helix.

143
Q

What does complimentary mean when describing DNA Bases?

A

A pairs with T (2 hydrogen bonds)
G pairs with C (3 hydrogen bonds)

143
Q

How does the phosphate sugar backbone form? Show diagram?

A

Condensation reactions between phosphates and OH on deoxyribose.

144
Q

What does the complimentary base pair of G and C look like?

A
145
Q

What does the complimentary base pair of A and T look like?

A
146
Q

What is cisplatin used for? What’s its structure? How does it work?

A

Cisplatin is used to prevent DNA replication in cancer cells.

The Cl- ligands are substituted out by N in guanines in DNA, which binds the complimentary strands together preventing the DNA from separating and preventing replication.

147
Q

What’s the difference between H1 NMR and C13NMR

A

No splitting patterns or integration traces in C13 NMR

148
Q

What solvents are used in NMR?

A

CCl4 for non polar samples, CDCl3 is deuterated chloroform (H with 2 neutrons is called deuterium) for polar molecules.

149
Q

What’s the reference material used for NMR? What’s its structure? Why is it used?

A

Tetramethylsilane (TMS)
TMSis used because: *it only gives one signal
*its signal is away from all the other H signals
*gives strong signal so only a small amount needed
*it is non-toxic
*it is inert
*it has a low boiling point and so can be removed from sample easily

150
Q

Spin coupling - what does it show

A

The amount of splitting = the number of adjacent H in different chemical environments on the next Carbon(s) over +1

151
Q

What are the three types of chromatography you need to know at A level? What information do they give out to identify compounds?

A

thin-layer chromatography (TLC)– a plate is coated with a solid and a solvent moves up the plate - information is Rf
* column chromatography (CC)– a column is packed with a solid and a solvent moves down the column - retention time can be measured here
* gas chromatography (GC)– a column is packed with a solid or with a solid coated by a liquid, and a gas is passed through the column under pressure at high temperature. - retention time can be measured here

152
Q

Why do samples separate in chromatography?

A

Each compound will have a different affinity for the mobile and stationary phases

153
Q

What’s retention time?

A

The time taken for a compound to travel through a column in chromatography

154
Q

How can you tell if a compound is more polar in chromatography?

A

The smaller the Rf/the higher the retention time the greater affinity for the polar stationary phase

155
Q

How can you tell if a compound is less polar in chromatography?

A

The higher the Rf/the smaller the retention time the greater affinity for the non-polar mobile phase

156
Q

What is the stationary phase used in all 3 types of chromatography made of, what types of compounds are used as mobile phases?

A

Either alumina (Al2O3) or silica (SiO2)
Mobile phase TLC or CC: Hexane,
Mobile phase GC: N2 or another inert gas

157
Q

What’s the equation to calculate Rf?

A

Rf = the distance from the start line to the centre of the sample dot/the distance from the start line to the solvent front

158
Q

What’s the chemical test for acyl chlorides? What’s the observation?

A

Add silver nitrate, produces effervesences and a rapid white precipitate

159
Q

What’s poly(chloroethene) used for?

A

Poly(chloroethene) is a polymer that is water proof, an electrical insulator and doesn’t react with acids. In its pure form it is a rigid plastic. In this un-plasticised form it is used make uPVC window frame coverings and guttering.
When a plasticiser is added PVC is used to make insulation on electrical wires, and waterproof clothing.

160
Q

How can the properties of poly(chloroethene) be modified

(specific IMF mentioned in brackets on answer, but generic)

A

If a plasticiser is added the intermolecular forces (permanent dipole-dipole forces between polymers) are weakened which allows the chains to move more easily, resulting in more flexibility in the polymer.

(alter the discussion of IMF each time)

NSFC Chemistry AQA A level Y13 (41 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions