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Jun237405201
IB/M/Jun23/E8 7405/
For Examiner’s Use
Question Mark 1 2 3 4 5 6 7 8 9
TOTAL
Monday 19 June 2023 Afternoon Time allowed: 2 hours
Materials
For this paper you must have:
- the Periodic Table/Data Booklet, provided as an insert (enclosed)
- a ruler with millimetre measurements
- a scientific calculator, which you are expected to use where appropriate.
Instructions
- Use black ink or black ball-point pen.
- Fill in the boxes at the top of this page.
- Answer all questions.
- You must answer the questions in the spaces provided. Do not write outside the box around each page or on blank pages.
- If you need extra space for your answer(s), use the lined pages at the end of this book. Write the question number against your answer(s).
- All working must be shown.
- Do all rough work in this book. Cross through any work you do not want to be marked.
Information
- The marks for questions are shown in brackets.
- The maximum mark for this paper is 105.
Please write clearly in block capitals.
Centre number Candidate number
Surname
Forename(s)
Candidate signature I declare this is my own work.
A-level
CHEMISTRY
Paper 2 Organic and Physical Chemistry
Do not write outside the Answer all questions in the spaces provided.^ box
(^0 1) This question is about rates of reaction.
Figure 1 shows apparatus used to measure the rate of reaction when an acid reacts with an excess of solid sodium hydrogencarbonate, NaHCO (^3)
When different monoprotic organic acids are used, the rates at which gas escapes can be used to compare the strengths of the acids.
A timer is started when the NaHCO 3 is added to the acid and the mass of CO 2 gas lost is recorded at regular intervals. (It is assumed that any change in mass is due to the loss of CO 2 )
Figure 1
0 1. (^1) Suggest a reason why using a conical flask instead of a beaker would give more accurate results in this experiment. [1 mark]
Do not write outside the (^0 2) A and B react together in the presence of an acid catalyst.^ box
A(aq) + 2 B(aq) → C(aq) + D(aq)
The rate equation for this reaction is
rate = k [B] 2 [H+]
Table 1 shows how the values of the relative initial rate vary with different concentrations of each reagent at the same temperature.
Table 1
Experiment
[A]
/ mol dm –
[B]
/ mol dm –
[H+]
/ mol dm –
Relative initial rate
1 0.40 0.20 0.10 1.
2 0.50 0.20 0.
3 0.40 0.10 0.
4 0.50 0.30 0.
0 2. (^1) Complete Table 1 by calculating the missing values. [3 marks]
(^0 2). 2 A suggested mechanism for the reaction is shown.
Step 1 B + H+^ → BH+
Step 2 BH+^ + B → B 2 H+
Step 3 B 2 H+^ + A → C + D
Deduce the rate-determining step for this reaction.
Give a reason for your answer. [2 marks]
Rate-determining step
Reason
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ANSWER IN THE SPACES PROVIDED
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Do not write outside the 0 3. (^2) Figure 4 shows an intermediate formed in the first step of a reaction mechanism of^ box methylbenzene.
Figure 4
Complete Figure 4 to show the reactant species and any curly arrows involved in the formation of the intermediate.
Draw a curly arrow on the intermediate to show how the product is formed.
Give the name of the reaction mechanism. [4 marks]
Name of mechanism
0 3. 3 Figure 5 shows the reactant species involved in the first step of a mechanism.
Figure 5
Complete Figure 5 to show the structure of the intermediate formed with curly arrows involved in its formation.
Give the name of the reaction mechanism. [4 marks]
Name of mechanism^12
Do not write outside the (^0 4) Acrylonitrile, H 2 C=CHCN, can be used as a starting material for the synthesis of^ box butane-1,4-diamine, as shown in this reaction scheme.
(^0 4). 1 Use IUPAC rules to name isomer W. [1 mark]
(^0 4). 2 Reaction 1 produces a mixture of W and two other isomers.
Draw the structures of the two other isomers.
Explain, by considering the mechanism of this reaction, why all three isomers are formed. [6 marks]
Do not write outside the The reaction scheme is repeated here.^ box
(^0 4). 3 Identify the reagent that is warmed with isomer W in reaction 2.
State the other reaction condition needed. [2 marks]
Reagent
Condition
0 4. (^4) State the reagent and reaction conditions needed for reaction 3.
Give an equation for reaction 3. [2 marks]
Reagent and conditions
Equation
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Do not write outside the 0 4. (^5) An incomplete equation for the formation of nylon 4,6 from five molecules of^ box butane-1,4-diamine and five molecules of hexanedioic acid is shown.
Deduce the values of x and y in this equation.
[2 marks]
x y
(^0 4). 6 Figure 6 shows a section of the nylon 4,6 polymer molecule.
Figure 6
Draw, on Figure 6 , another section of nylon 4,6 polymer showing two hydrogen bonds between the two sections. [2 marks] 15
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Do not write outside the 0 5. (^4) Table 2 shows data from the 1 H NMR spectrum for compound Z. box
Table 2
Chemical shift ẟ / ppm 4.10 2.60 2.56 2.19 1.
Integration ratio 2 2 2 3 3
Splitting pattern quartet triplet triplet singlet triplet
Explain what can be deduced from the splitting patterns and chemical shift values for the peaks at ẟ = 4.10 ppm and at ẟ = 1.26 ppm
Deduce the part of the structure of Z that causes the peaks at ẟ = 4.10 ppm and ẟ = 1.26 ppm
Use Table B in the Data Booklet to help you answer this question. [5 marks]
Peak at ẟ = 4.10 ppm
Peak at ẟ = 1.26 ppm
Part of structure
0 5. 5 Deduce the part of the structure of Z that causes the peak at ẟ = 2.19 ppm [1 mark]
Part of structure
Do not write outside the Figure 9 shows the 1 H NMR spectrum of compound Z.^ box
Figure 9
(^0 5). 6 Suggest why it would be difficult to determine the structure of Z using the spectrum in Figure 9 , without the information in Table 2 on page 13. [1 mark]
Do not write outside the (^0 6) A student plans a series of chemical tests to confirm the identities of four organic^ box liquids.
This is the student’s method.
To separate test tubes containing samples of each liquid:
Test 1 add potassium dichromate(VI) solution and warm gently
Test 2 add Fehling’s solution and cool in iced water
Test 3 add sodium hydrogencarbonate solution and test any gas produced with a lighted splint
Test 4 add bromine water and shake at room temperature.
(^0 6). 1 Identify the missing reagent needed in Test 1. [1 mark]
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Do not write outside the 0 6. (^2) In addition to the missing reagent in Test 1 , there is a mistake in the method for two^ box of the other tests.
State the two mistakes.
Suggest how each of the mistakes should be corrected. [2 marks]
Mistake 1
Suggestion
Mistake 2
Suggestion
(^0 6). 3 The missing reagent is added and the mistakes are corrected.
Identify the liquid(s), J , K , L and M , that would react in each test.
State the expected observation for each reaction. [8 marks]
Liquid(s) that react in Test 1
Expected observation
Liquid(s) that react in Test 2
Expected observation
Liquid(s) that react in Test 3
Expected observation
Liquid(s) that react in Test 4
Expected observation
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ANSWER IN THE SPACES PROVIDED
Do not write outside the (^0 7) A gas syringe that does not have any graduations is calibrated using a known mass of^ box propanone (boiling point = 56.2 °C).
The sealed gas syringe contains 0.146 g of propanone ( M r = 58.0) at a temperature of 95 °C and a pressure of 103 kPa
0 7. (^1) Calculate the volume, in cm^3 , of propanone in the gas syringe.
The gas constant, R = 8.31 J K−^1 mol−^1 [4 marks]
Volume of propanone cm^3
(^0 7). 2 The gas syringe is then cooled to 75 °C, without changing the pressure.
Calculate the decrease in volume.
(If you were unable to calculate the volume in Question 07.1 , you should use the volume 89 cm^3. This is not the correct answer.) [2 marks]
Decrease in volume cm^3
