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Edexcel Jun 2015 Paper 4 Q15
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![15 Aspirin can be manufactured from sodium phenoxide using the process shown below. ONa + CO2 (g) Step 1 OH OH Step 2 (s) Sodium phenoxide COONa (s) COOH (s) Step 3 Overall yield for process = 79% (a) Explain one effect of an increase in pressure on the reaction in Step 1. Aspirin OCOCH3 COOH (s) (2)(b) The overall yield for this process is 79%. Calculate the mass, in tonnes, of aspirin that would be formed from 2.5 tonnes of sodium phenoxide. Give your answer to two significant figures. [Molar masses / g mol1: sodium phenoxide = 116; aspirin = 180] (c) Classify the reaction type in Step 3 and suggest a suitable reagent. (3) (2) Reaction typeReagent(Total for Question 15 = 7 marks) *P42978A02128* 21 Turn over<br />](https://learnah.org/wp-content/uploads/2018/08/l_smalljpgJune_2015_QP_-_Unit_4_Edexcel_Chemistry_A-level_15.jpg)
![Reject Mark Question Number 15 (a) Correct Answer EITHER (consideration of kinetics) Rate of reaction increases (1) As collisions are more frequent / increases frequency of collisions / more collisions per second IGNORE Just more collisions or just more successful collisions (1) OR (if assumes an equilibrium reaction) Yield increases / eqm shifts to RHS (1) Since fewer moles of gas / no moles of gas / fewer molecules of gas (on RHS) (1) MUST AWARD MARKS BY ONLY CONSIDERING ONE OF THE ROUTESCANNOT score full marks via one mark from each route if MIX UP KINETICS AND EQUILIBRIUM ARGUMENTS Eg Rate increases, so yield of product increases scores (1)<br />
Mark Rejec t Question Number 15 (b) Correct Answer [FIRST, CHECK THE FINAL ANSWER IF ANSWER = 3.1 (tonnes), award 3 marks] EITHER 1 tonne C6H5ONa : 180/116 tonnes C6H4(OH)(CO2H) (1) 2.5 tonnes C6H5ONa : (180/116) x 2.5 (tonnes) C6H4(OH)(CO2H) at 100% yield (1) (= 3.879 tonnes) So actual yield = (180/116) x 2.5 x 79/100 (3.06) = 3.1 (tonnes) (1) OR Moles C6H5ONa (= 2.5 x 106116) = 21 551.7 (mol) Moles C6H5ONa (79% yield) (= 21 551.7 x 0.79) = 17025.8 (mol) Mass C6H5ONa (= 17025.8 x 180 = 3064644 g = 3.06 tonnes) = 3.1 (tonnes) to 2SF Correct answer TO 2 SF, no working (3) Can work in g (instead of tonnes) until final answer So final answer of 3.06 (tonnes) scores M1 and M2 only Award only (1) mark for 3.07 (tonnes) without working (1) (1) (1)<br />
Reject Mark Correct Answer Esterification / acylation / ethanoylation ALLOW acetylation OR (nucleophilic) addition-elimination BOTH words (addition and elimination) are needed for this option IGNORE Condensation (1) (1) CH3COCl / ethanoyl chloride OR (CH3CO)2O / ethanoic anhydride ALLOW CH3COOH / ethanoic acid (in presence of H2SO4) Correct displayed / skeletal formulae IGNORE JUST acid anhydride / acid chloride (TOTAL FOR QUESTION 15 = 7 marks) Question Number 15 (c)<br />](https://learnah.org/wp-content/uploads/2018/08/June_2015_MS_-_Unit_4_Edexcel_Chemistry_A-level_15-0.jpg)
