AQA AS CHEMISTRY 7404/2 Paper 2 Organic and Physical Chemistry Version: 1.0 Final *JUN*/ QUESTION PAPER & MARKING SCHEME/ [MERGED] Mark scheme June 2023

AQA AS CHEMISTRY 7404/2 Paper 2 Organic and Physical Chemistry Version: 1.0 Final *JUN* IB/M/Jun23/E6 7404/2 For Examiner’s Use Question Mark 1 2 3 4 5 6 7 8 Section B TOTAL Tuesday 23 May 2023 Morning Time allowed: 1 hour 30 minutes Materials For this paper you must have: • the Periodic Table/Data Sheet, 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 80. Advice You are advised to spend about 65 minutes on Section A and 25 minutes on Section B. Please write clearly in block capitals. Centre number Candidate number Surname Forename(s) Candidate signature I declare this is my own work. AS CHEMISTRY Paper 2 Organic and Physical Chemistry 2 *02* IB/M/Jun23/7404/2 Do not write outside the Section A box Answer all questions in this section. 0 1 This question is about the analysis of organic compounds. For each pair of compounds in Questions 01.1 and 01.2, give a reagent (or combination of reagents) that could be added separately to each compound in a single reaction to distinguish between them. State what is observed in each case. 0 1 . 1 CH3CH2CH2CHO and CH3CH2CH(OH)CH3 [3 marks] Reagent(s) Observation with CH3CH2CH2CHO Observation with CH3CH2CH(OH)CH3 0 1 . 2 Cyclohexane and cyclohexene [3 marks] Reagent(s) Observation with cyclohexane Observation with cyclohexene 3 *03* Turn over ► IB/M/Jun23/7404/2 Do not write outside the box 0 1 . 3 Table 1 gives the precise relative molecular masses (Mr) of some organic compounds measured using high resolution mass spectrometry. Table 1 Molecular formula C5H12 C5H10 C6H6 Mr 72.1416 70.1260 to be calculated Use these data to find the relative atomic masses (Ar) of hydrogen and carbon. Give your answers to 4 decimal places. Use these calculated Ar values to find the relative molecular mass (Mr) of C6H6 Give your answer to 4 decimal places. [3 marks] Ar of hydrogen Ar of carbon Mr of C6H6 9 4 *04* IB/M/Jun23/7404/2 Do not write outside the box 0 2 This question is about fuels. 0 2 . 1 Crude oil is separated into fractions by fractional distillation. State the meaning of the term ‘fraction’ in this context. [1 mark] 0 2 . 2 Petrol for cars contains branched and cyclic alkanes produced by catalytic cracking. Identify the catalyst used in this process. [1 mark] 0 2 . 3 3-Ethyl-4-methylhexane is a branched alkane in petrol. Draw the skeletal formula of this alkane. [1 mark] 0 2 . 4 Give the equation for the complete combustion of 3-ethyl-4-methylhexane. Use the molecular formula for 3-ethyl-4-methylhexane in your equation. [2 marks] 5 *05* Turn over ► IB/M/Jun23/7404/2 Do not write outside the box 0 2 . 5 Carbon dioxide is a product from the combustion of petrol in cars. Carbon dioxide acts as a greenhouse gas when it absorbs infrared radiation. Give one reason why carbon dioxide absorbs infrared radiation. [1 mark] 0 2 . 6 Nitrogen monoxide (NO) is formed when petrol is burned in cars. State one environmental problem that NO causes. State what is used to remove NO from the exhaust gases formed in petrol-fuelled cars. [2 marks] Environmental problem Removal of NO 0 2 . 7 Petrol sold in the UK contains 10% bioethanol. Bioethanol is ethanol made from crops by fermentation and is considered to be carbon-neutral. State what is meant by the term ‘carbon-neutral’. [1 mark] Turn over for the next question 9 6 *06* IB/M/Jun23/7404/2 Do not write outside the box 0 3 This question is about reactions of halogenoalkanes with hydroxide ions. 0 3 . 1 Outline the mechanism for the nucleophilic substitution reaction of 1-bromobutane with sodium hydroxide. [2 marks] 7 *07* Turn over ► IB/M/Jun23/7404/2 Do not write outside the A student investigated the rate of nucleophilic substitution of halogenoalkanes with box hydroxide ions. Identical concentrations of 1-bromobutane and 1-iodobutane were reacted separately with sodium hydroxide solution under the same conditions. The concentration of halide ions was monitored during each experiment. Figure 1 shows the student’s results. Figure 1 0 3 . 2 State how Figure 1 shows that the rate of reaction of 1-iodobutane is faster than the rate of reaction of 1-bromobutane. State why the rates are different