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AQA MERGED QUESTION PAPER AND MARK SCHEME CHEMISTRY PAPER 2-7404 ORGANIC AND PHYSICAL CHEMISTRY FOR MAY 2024
Typology: Exams
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For Examiner’s Use
Question Mark 1 2 3 4 5 6 7
Section B
TOTAL
Section A
Answer all questions in this section.
(^0 1) This question is about the analysis of organic compounds.
(^0 1). 1 Table 1 shows the results of chemical tests on three organic compounds.
Complete the empty boxes in the table.
Table 1
Chemical test
Add bromine water
orange to colourless
no visible change
no visible change bubbles of gas no visible change
Warm with Fehling’s solution
no visible change no visible change
[ 3 marks]
Do not write outside the (^0 2) This question is about infrared spectroscopy.^ box
(^0 2). 1 Compounds A and B both have the molecular formula C 4 H 8 O 2
Figure 1 shows the infrared spectra of compounds A and B.
Use the infrared spectra to deduce a possible structural formula for compound A and a possible structural formula for compound B. [2 marks]
Figure 1
Possible structural formula of A Possible structural formula of B
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Do not write outside the 0 2. (^2) Figure 2 shows the infrared spectrum of either pent-1-ene or 2-methylbut-2-ene.^ box
Figure 2
Outline how to use the infrared spectrum to determine whether the compound is pent-1-ene or 2-methylbut-2-ene. [ 2 marks]
Question 2 continues on the next page
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Do not write outside the Turn over for the next question^ box
Do not write outside the (^0 3) This question is about CFCl 3^ box
CFCl 3 used to be the propellant in most aerosol cans.
0 3. (^1) Use IUPAC rules to name CFCl 3 [ 1 mark]
(^0 3). 2 Give an equation for each of the two propagation steps in the conversion of CHFCl 2 into CFCl 3 [ 2 marks]
Equation 1
Equation 2
(^0 3). 3 In the presence of ultraviolet radiation, CFCl 3 breaks down in the upper atmosphere to form chlorine free radicals.
Give an equation for this reaction. [ 1 mark]
Do not write outside the 0 4. (^1) Compound J is one of a pair of stereoisomers.^ box
Explain:
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Question 4 continues on the next page
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Do not write outside the 0 4. (^3) Explain why compound K is the major product in the reaction in Question 04.2.^ box [ 3 marks]
Turn over for the next question
Do not write outside the (^0 5) This question is about the volumes of gases involved in some reactions.^ box
(^0 5). 1 Magnesium reacts with hydrochloric acid.
Mg(s) + 2 HCl(aq) → MgCl 2 (aq) + H 2 (g)
0.400 g of magnesium is added to 20.0 cm 3 of 1.50 mol dm–3^ hydrochloric acid.
Identify the limiting reagent.
Justify your answer.
Calculate the volume, in m^3 , of hydrogen produced at 101 kPa and 15 °C
The gas constant, R = 8.31 J K–1^ mol – [ 7 marks]
Limiting Reagent
Justification
Volume of hydrogen m^3
Do not write outside the 0 6 A student investigates the effect of changing the temperature on the rate of hydrolysis^ box of 1-iodobutane.
The student follows this method:
(^0 6). 1 Identify the yellow precipitate formed in the reaction. [ 1 mark]
The student repeats the experiment at different temperatures.
Table 2 shows the student’s results.
Table 2
Temperature / °C Time t / s (^1) t / s –
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Do not write outside the 0 6. 2^ box Plot the values of
1 t against temperature on the grid.
Draw a line of best fit.
Use your graph to predict the time, in s, when the cross is no longer visible at 50 °C [3 marks]
Time s
Question 6 continues on the next page
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Do not write outside the (^0 7) This question is about propanoic acid (CH 3 CH 2 COOH).^ box
The equation for the oxidation of propan-1-ol under reflux to form propanoic acid is shown.
0 7. (^1) Acidified potassium dichromate(VI) is used as the oxidising agent.
State the colour change in this reaction. [ 1 mark]
(^0 7). 2 A second organic product, X, is formed in small quantities. The boiling point of X is 49 °C
Identify X. [ 1 mark]
(^0 7). 3 Propanoic acid molecules cannot be separated from the reaction mixture by simple distillation because propanoic acid forms hydrogen bonds with water molecules.
Complete the diagram to show how the propanoic acid molecule interacts with one water molecule through hydrogen bonding. Include in the diagram all the partial charges and lone pairs of electrons involved in this hydrogen bond. [3 marks]
Question 7 continues on the next page
Do not write outside the An alternative method of preparing propanoic acid is shown.^ box
Step 1 involves the reaction of bromoethane with sodium cyanide under reflux in a suitable solvent.
(^0 7). 4 Name and outline the mechanism for Step 1. [ 3 marks]
Name of mechanism
Outline of mechanism
(^0 7). 5 Suggest one reason why water is not a suitable solvent for Step 1. [ 1 mark]
