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Actual 2024 AQA A-LEVEL CHEMISTRY 7405/2 Paper 2 Merged Question Paper + Mark Scheme + Insert AQA= Please write clearly in block capitals. Centre number Candidate number Surname Forename(s) Candidate signature | declare this is my own work. A-level CHEMISTRY Paper 2 Organic and Physical Chemistry Tuesday 18 June 2024 Morning Materials For this paper you must have: e the Periodic Table/Data Booklet, provided as an insert (enclosed) ¢ aruler with millimetre measurements ¢ ascientific calculator, which you are expected to use where appropriate. Instructions e Use black ink or black ball-point pen. Fill in the boxes at the top of this page. « Answer all questions. e 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. Time allowed: 2 hours For Examiner's Use Question Mark J 7405201 IB/M/Jun24/G4006/E6 7405/2 1 Do not write outside the Answer all questions in the spaces provided. box Propanone reacts with bromine in alkaline conditions. CHsCOCH3 + Bre + OH” — CH3sCOCH2Br + Br- + H20 The rate equation for this reaction is Rate = k [CHsCOCHs] [OH] [o[4].[4} Sketch a graph on the axes provided to show how, at constant temperature, the concentration of bromine changes during this reaction. [1 mark] [Br] / mol dm-$ Time /s 02 IB/M/Jun24/7405/2 2 Do not write outside the [0] 1].[3] Figure 1 shows an incomplete mechanism for this reaction. DOK. Figure 1 H H ‘i HH \ HH oad ae H \ Step 1 H \ — } =0 — c—o +H,0 H x I i. 4 OH - / ~H H7~ \ H H H H \_ CH \, _-H Ho \ Step 2 4 c—o Pe C=oO + Br df HS Hm \ / sr H Br—Br H Complete the mechanism in Figure 1 by adding four curly arrows and any relevant lone pair(s) of electrons. [4 marks] [o[4].[4] Use evidence from the rate equation to explain why Step 1 is the rate determining step. [1 mark] 11 INI IB/M/Jun24/7405/2 4 Do not write outside the box Turn over for the next question DO NOT WRITE/ON THIS PAGE ANSWER IN THE/SPACES PROVIDED Turn over > INN IB/M/Jun24/7405/2 5 Do not write outside the [o|2].[2] Give the expression for the equilibrium constant, Ke box Calculate the value of Ke and deduce its units. [4 marks] K Value of Ke Units [0[2].[3| Explain why the amount of S increases when water is added to the equilibrium mixture. [2 marks] 8 Turn over for the next question Turn over > 07 IB/M/Jun24/7405/2 7 (o[3][2] INN Do not write outside the This question is about hydrocarbons. bok Eicosane (C20H.2) can be cracked by heating to 700 K in the presence of a catalyst. The products are © an aromatic hydrocarbon CgHio © an alkane CeHi4 * another alkane. CaoH42 —> CaHto + CeHi4 + Complete the equation for this reaction. Give a suitable catalyst for this reaction. [2 marks] Catalyst Figure 2 shows the °C NMR spectrum for the aromatic hydrocarbon CsH1o Figure 2 T T T T T T T 200 180 160 140 120 100 80 60 40 20 0 6/ppm IB/M/Jun24/7405/2 8 10 Do not write outside the [0] 3].[4] A sample of butane has a volume of 20 cm® at room temperature and pressure. box The sample is burned completely in 1350 cm° of air. The final mixture is cooled to room temperature and pressure. CaHio + 6302 > 4CO2 + 5H20 Calculate the total volume of gas in the final mixture. Assume that air contains 21% by volume of oxygen. [4 marks] Total volume of gas remaining cm? [0] 3].[5| Natural gas is used in power stations to produce electricity. Natural gas contains sulfur impurities. Sulfur dioxide forms when these impurities are burned. State an environmental problem caused by sulfur dioxide. Give the formula of a compound that is used to help remove sulfur dioxide from the combustion products. [2 marks] Environmental problem Formula of compound 10 IB/M/Jun24/7405/2 10 11 Do not write outside the box Turn over for the next question DO NOT WRITE/ON THIS PAGE ANSWER IN THE/SPACES PROVIDED Turn over > INIA IB/M/Jun24/7405/2 11 INIA 13 Question 4 continues on the next page Turn over > IB/M/Jun24/7405/2 Do not write outside the box 13 14 Do not write outside the [0] 4].[3] In Step 2 the reaction mixture from Step 1 is shaken with aqueous sodium carbonate. box State the purpose of the sodium carbonate. Suggest a precaution that should be taken while this mixture is shaken in the separating funnel. Give a reason for your suggested precaution. [3 marks] Purpose of sodium carbonate Precaution Reason [0[4].[4] Give the reason for the use of anhydrous magnesium sulfate in Step 3. [1 mark] [0[4].[5| Suggest how the purity of the ester can be confirmed during the distillation in Step 4. 1 [1 mark] IB/M/Jun24/7405/2 14 16 Do not write outside the Compounds V, W, X and Y are isomers with the molecular formula CsH10O2 box Isomers V and W are carboxylic acids with formulas that can be written as CaH3COOH [o[6].[1| Give an equation for the reaction of CsHsCOOH with sodium hydrogencarbonate. [1 mark] [o[6].[2| Isomer V has an asymmetric carbon atom. Deduce the structure of V. [1 mark] [o[6].[3| Isomer W has four peaks in its 'H NMR spectrum. Deduce the structure of W. Deduce the integration ratio for the four peaks in the 'H NMR spectrum of W. [2 marks] Structure Integration ratio 16 IB/M/Jun24/7405/2 16 17 Do not write outside the [o|6|.[4] lsomer X has three singlets with integration ratio 1:3:6 in its 'H NMR spectrum. bass Deduce the structure of X. Explain why the peaks in the 'H NMR spectrum are singlets. [2 marks] Structure Explanation Question 6 continues on the next page Turn over > INIA IB/M/Jun24/7405/2 17 1 A 9 19 Do not write outside the Compound L (M, = 88.0) contains carbon, hydrogen and oxygen only. Bo A 6.56 x 104 mol sample of L burns completely in air to form 2.62 x 10-° mol of water and 2.62 x 10 mol of carbon dioxide. Deduce the formula of L. Show your working. [4 marks] Formula of L 4 Turn over > IB/M/Jun24/7405/2 19 20 Do not write outside the This question is about an organic synthesis. bok Step 1 Step 2 CH,CH,CH= CH, ———» CH,CH,CHBrCH, ———» Compound J [sep 3 CH3CH,COCH, | see 4 CH,CH,C(OH)CNCH, [o[8].[4] Name the mechanism in Step 1. State the reagent(s) used for Step 1. [2 marks] Name of mechanism Reagent(s) [o[8].[2| Identify compound J. State the reagent(s) and conditions needed for Step 2. [2 marks] Compound J Reagent(s) and conditions INA IB/M/Jun24/7405/2 20 
