AQA A-Level Chemistry Paper 2 - SOLUTION BANK (Q+A)

Building a solution bank of all the questions/answers.

If you can remember a specific question that has not been contributed, please add it down below. Thank you in advance :five:

Question 1
1. This question is about amines.
1.1. Give an equation for the preparation of 1,6-diaminohexane by the reaction of 1,6-dibromohexane with an excess of ammonia. (2 marks)

Spoiler

1.2. Complete the mechanism for the reaction of ammonia with 6-bromohexylamine to form 1,6-diaminohexane. (2 marks)

Spoiler

Suggest the structure of a cyclic secondary amine that can be formed as a by-product in this reaction. (1 mark)

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1.3. 1,6-diaminohexane can also be formed in a two-stage synthesis, starting from 1,4-dibromobutane.
Suggest a reagent and a condition for each stage in the alternative synthesis.

Stage 1

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Stage 2:

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Question 2
deduce formula of carboxylic acid, high res mass spec.

Question 3
golf balls.

Question 4
4. Substances P and Q react in a solution at a constant temperature.
The initial rate of reaction was studied in three experiments by measuring the change in concentration of P over the first 5 seconds of the reaction.
The data obtained are shown in table 1.
Q4 Table 1 .png

4.1. Complete Table 2 to show the initial rate of reaction of P for each experiment.

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4.2. Calculate the order of reaction with respect to P and Q.

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Question 5
The rate constant, k = Ae^-E_a/RT
For this reaction at 25ºC, k = 3.46x10^-8 s^-1
The activation energy Ea = 96.2 kJ mol^-1
The gas constant R = 8.31 J K mol^-1

Calculate a value for the Arrhenius constant A for this reaction. Give the units for A.

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Question 6
6. Compounds A and B both have the molecular formula C₄H₈Br₂. A has a singlet, a triplet and a quartet in its H¹ NMR spectrum. B has two singlets in its H¹ NMR spectrum

6.1. Draw the structure of A and B.

Question 7
7.
Isomer X Isomer Y

7.1. Give the IUPAC name of isomer X. (1 mark)

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7.2. Explain how and why isomers X and Y can be distinguished by comparing each of their:

•

Boiling points
[list]

•

C¹³ NMR spectra
[list]

•

IR spectra

Use data from Tables A and C in the data booklet in your answer. (6 marks)

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Question 8
8. Paracetamol is a medicine commonly used to relieve mild pain traditionally paracetamol has been made in industry in a 3-step process.

8.1. Name the mechanism of the reaction in step 1

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8.2. Complete the equation for the reaction in step 2.

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In step 3, other aromatic products are formed as well as paracetamol
8.3. Draw the structure of one of these other aromatic products.

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Chemists have recently developed a two step process to produce paracetamol from phenol. In the first step phenol is oxidised to Hydroquinone.

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In the second step hydroquinone reacts with ammonium to form paracetamol. complete the equation for the second step.

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Question 9

Question 10

Question 11

Question 12
12. This question is about chromatography.
12.1. Suggest why 2 solvents were used. (2 marks)

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12.2 Deduce the minimum number of amino acids present. (1 mark)

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12.3. How can the spots be located?

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12.4 peptide chain hydrolysis.

Question 13

13.
13.1 Add H bonds to the diagram

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13.2
13.3 Explain what is meant my the term complimentary in the context of DNA. (2 marks)

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(edited 4 years ago)

Table 2 qu4.png14.1KB

Q4 Table 1 .png46.2KB

Table 1 qu 4.png28.0KB

Phenol.png42.7KB

paracetamol.png29.8KB

Reply 1

Fahad9

1

Hopefully it will work out by tonight 🤞

Reply 2

This question is about isomers
Give a reagent and observations for a test – tube reaction to distingujish between 2- methylbutan 1 ol and 2-methylbutan-2-ol
Reagent
Observation with 2-methylbutan-1-ol
Observation eith 2-methylbutan-2-ol

Reply 3

OP

Reagent is acidified potassium dichromate. It goes from orange to green with the 2º alcohol, because is oxidises the alcohol (to a ketone). With 3º alcohol there is no change / remains orange. 3º alcohols cannot be oxidised.

Original post by jamesctu

This question is about isomers
Give a reagent and observations for a test – tube reaction to distingujish between 2- methylbutan 1 ol and 2-methylbutan-2-ol
Reagent
Observation with 2-methylbutan-1-ol
Observation eith 2-methylbutan-2-ol

Do you know what the numbers of the questions are so i can create a solution bank?

Reply 4

Original post by ÷by0

Reagent is acidified potassium dichromate. It goes from orange to green with the 2º alcohol, because is oxidises the alcohol (to a ketone). With 3º alcohol there is no change / remains orange. 3º alcohols cannot be oxidised.

Do you know what the numbers of the questions are so i can create a solution bank?

i think that question 6

Reply 5

Compounds A and B both have the molecular formula c4h8Br2
A has a singlet,a triplet and a quartet in its 1H NMR spectrum.
B has only two singlets in its 1H NMR spectrum
Draw the structure for each A and B
A B

Reply 6

OP

Original post by jamesctu

Compounds A and B both have the molecular formula c4h8Br2
A has a singlet,a triplet and a quartet in its 1H NMR spectrum.
B has only two singlets in its 1H NMR spectrum
Draw the structure for each A and B
A B

for A:
Singlet (S)=> no neighbouring H environments
Triplet (T)=> 2 H adjacent
quartet (Q) => 3 adjacent

CH2-CBr2-CH2-CH3
(S) (Q) (T)

For B:

Singlets mean all Hydrogens have no hydrogenates on their neighbouring carbon
=> (BrH2C)-CBr-(CH3)2

Reply 7

Original post by ÷by0

for A:
Singlet (S)=> no neighbouring H environments
Triplet (T)=> 2 H adjacent
quartet (Q) => 3 adjacent

CH2-CBr2-CH2-CH3
(S) (Q) (T)

For B:

Singlets mean all Hydrogens have no hydrogenates on their neighbouring carbon
=> (BrH2C)-CBr-(CH3)2

this is still all in the 6 question i think

Reply 8

OP

thanks

Original post by jamesctu

this is still all in the 6 question i think

Reply 9

phosphene

14

DNA -

Part one was the hydrogen bond drawings

Then you had to circle the nucleotides (vague wording lol)

Explain why strands complementary

Reply 10

q8
calculate the mass in kg of hydroquinone (mr=110.0) needed to produce 250 kg of parecetamol

Original post by ÷by0

thanks

Reply 11

phosphene

14

Not 100% sure but I think 12 was the TLC question

Minimum number of amino acids (8 or 7 can’t recall)
How to see them? Something about UV
How to hydrolyse them (hcl probs)

Reply 12

Original post by phosphene

Not 100% sure but I think 12 was the TLC question

Minimum number of amino acids (8 or 7 can’t recall)
How to see them? Something about UV
How to hydrolyse them (hcl probs)

what did u get for the wavelength
i got
F
G
E

Reply 13

OP

i don't remember letter orders, but it was ester, the alcohol, then carboxylic acid i think.

Original post by jamesctu

what did u get for the wavelength
i got
F
G
E

Reply 14

Original post by ÷by0

i don't remember letter orders, but it was ester, the alcohol, then carboxylic acid i think.

this was the displayed formula of each one what was the order

OP

E, G, F, i think. The bottom two graphs had broad OH peaks.

Original post by jamesctu

this was the displayed formula of each one what was the order

Reply 16