Partial preview of the text
Download Actual 2024 AQA AS CHEMISTRY 7404/2 Paper 2 Merged Question Paper + Mark Scheme + Insert and more Exams Chemistry in PDF only on Docsity!
Actual 2024 AQA AS CHEMISTRY 7404/2 Paper 2 Merged Question Paper + Mark Scheme + Insert AQA= Please write clearly in block capitals. Centre number Candidate number Surname Forename(s) Candidate signature AS CHEMISTRY Paper 2 Organic and Physical Chemistry | declare this is my own work. Tuesday 21 May 2024 Morning Time allowed: 1 hour 30 minutes Materials For this paper you must have: « the Periodic Table/Data Sheet, provided as an insert (enclosed) Question Mark * atuler with millimetre measurements ¢ a scientific calculator, which you are expected to use where appropriate. For Examiner's Use Instructions e 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. 7 If you need extra space for your answer(s), use the lined pages at the end of Section B this book. Write the question number against your answer(s). All working must be shown. TOTAL ¢ Do all rough work in this book. Cross through any work you do not want to be marked. olalalwlrm|a Information « The marks for questions are shown in brackets. ¢ The maximum mark for this paper is 80. Advice You are advised to spend about 65 minutes on Section A and 25 minutes on Section B. IB/M/Jun24/G4001/V7 7404/2 Section A Answer all questions in this section. This question is about the analysis of organic compounds. {o[4].[1] Table 1 shows the results of chemical tests on three organic compounds. Complete the empty boxes in the table. Table 1 O° Chemical test ZA OH fe) Add bromine orange to no visible change water colourless no visible change bubbles of gas no visible change Warm with Fehling’s no visible change no visible change solution [3 marks] IM IB/M/Jun24/7404/2 Do not write outside the box This question is about infrared spectroscopy. [o[2].[1] Compounds A and B both have the molecular formula C4HsO2 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. Figure 1 100 Percentage 50- transmittance (e) T T T y T y T 4000 3000 2000 1500 1000 500 Wavenumber / cm-1 100 Percentage 50- transmittance ie) T T T T T T T 4000 3000 2000 1500 1000 500 Wavenumber / cm-1 Possible structural formula of A [2 marks] Compound A Compound B Possible structural formula of B IMI IB/M/Jun24/7404/2 Do not write outside the box [o]2].[2] Figure 2 shows the infrared spectrum of either pent-1-ene or 2-methylbut-2-ene. Figure 2 100 Percentage transmittance 507 ie} T T T T T T 4000 3000 2000 1500 1000 500 Wavenumber / cm-1 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 Turn over > IMI IB/M/Jun24/7404/2 Do not write outside the box Turn over for the next question DO NOT WRITE/ON THIS PAGE ANSWER IN THE/SPACES PROVIDED IMI Turn over > IB/M/Jun24/7404/2 Do not write outside the box {o[3}.[2] {o[3|.[3] This question is about CFCl3 CFCls used to be the propellant in most aerosol cans. Use IUPAC rules to name CFCls [1 mark] Give an equation for each of the two propagation steps in the conversion of CHFCl, into CFCl3 [2 marks] Equation 1 Equation 2 In the presence of ultraviolet radiation, CFCls breaks down in the upper atmosphere to form chlorine free radicals. Give an equation for this reaction. [1 mark] 08 IB/M/Jun24/7404/2 Do not write outside the box 10 10 [o[4].[1] Compound J is one of a pair of stereoisomers. CH3 CH3— CH H . ~ 4 Zon CH3— CH, CH,— CH3 Compound J Explain: « what stereoisomers are « how E-Z stereoisomerism occurs e how the Cahn-Ingold-Prelog rules can be used to decide whether compound J is an E or Zisomer. [6 marks] IB/M/Jun24/7404/2 Do not write outside the box 11 11 Question 4 continues on the next page IMI Turn over > IB/M/Jun24/7404/2 Do not write outside the ‘box 13 13 {o[4].[3] Explain why compound K is the major product in the reaction in Question 04.2. [3 marks] Turn over for the next question Turn over > IMI IB/M/Jun24/7404/2 Do not write outside the box 14 14 This question is about the volumes of gases involved in some reactions. Magnesium reacts with hydrochloric acid. Mg(s) + 2HCl(aq) — MgClo(aq) + H2(g) 0.400 g of magnesium is added to 20.0 cm? of 1.50 mol dm- hydrochloric acid. Identify the limiting reagent. Justify your answer. Calculate the volume, in m?, of hydrogen produced at 101 kPa and 15 °C The gas constant, R = 8.31 J K* mol" [7 marks] Limiting Reagent Justification Volume of hydrogen m? IB/M/Jun24/7404/2 Do not write outside the box 16 16 {o[s][4] A student investigates the effect of changing the temperature on the rate of hydrolysis of 1-iodobutane. The student follows this method: Add 5 cm of ethanol and 4 drops of 1-iodobutane to a test tube. Mark this test tube with a cross (below the level of the liquid). Add 5 cm® of 0.05 mol dim silver nitrate solution to a separate test tube. Place a stopper in both test tubes. Place both test tubes in a beaker of water at a known temperature (between 5 and 60 °C). ¢ After 5 minutes, pour the silver nitrate solution into the test tube containing 1-iodobutane and start a timer. ¢ Look through the transparent reaction mixture in the test tube towards the cross. ¢ Stop the timer when the cross is no longer visible due to the yellow precipitate formed. 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 4 s' 6 125 0.0080 15 83 0.0120 28 50 0.0200 34 38 0.0263 42 26 0.0385 16 IB/M/Jun24/7404/2 Do not write outside the box 17 17 [o[6].[2] Plot the values of + 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 0.07 74> [3 marks] i t coo t i t i i i i i i i t i i 0.06 t Coo t i i T i t T t i L I tT i T 0.05} 0.04 Vig 0.03 0.02 0.01 i t “EERE EEE i i t t t T t i i i i 0 10 20 30 40 Temperature / °C Time Question 6 continues on the next page 17 Turn over > IB/M/Jun24/7404/2 Do not write ‘outside the ‘box 19 19 This question is about propanoic acid (CH3CH2COOH). The equation for the oxidation of propan-1-ol under reflux to form propanoic acid is shown. H HH HoH O | | | | | 4g HEE 60H + 210) —> HE ee + HO H HH H oH OH Acidified potassium dichromate(VI) is used as the oxidising agent. State the colour change in this reaction. [1 mark] A second organic product, X, is formed in small quantities. The boiling point of X is 49 °C Identify X. [1 mark] 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 Turn over > IB/M/Jun24/7404/2 Do not write outside the box 20 Do not write outside the An alternative method of preparing propanoic acid is shown. box HoH H OH H oH O | | Step 1 | | Step 2 | | 4 Hoe — HE EON — He ee HoH H oH HoH OH Step 1 involves the reaction of bromoethane with sodium cyanide under reflux ina suitable solvent. Name and outline the mechanism for Step 1. [3 marks] Name of mechanism Outline of mechanism {5 | Suggest one reason why water is not a suitable solvent for Step 1. [1 mark] 20 IB/M/Jun24/7404/2 
