AQA Jun 2017 Paper 2 Q7 (with explained solutions) |

Skip to content

AQA Jun 2017 Paper 2 Q7

Answers available below

14Test-tube reactions can be used to identify the functional groups in organic molecules. You are provided with samples of each of the four compounds. Describe how you could distinguish between all four compounds using the minimum number of tests on each compound. You should describe what would be observed in each test. [6 marks] 0 7 0 7 . 1 *14* IB/M/Jun17/7405/2<br />

Show answer

This question is marked using Levels of Response. Refer to the Mark Scheme Instructions for Examiners for guidance. Level 3 All stages are covered and each stage is generally correct and virtually complete. 5-6 marks Level 2 3-4 marks Level 1 1-2 marks Answer is communicated coherently and shows a logical progression from Stage 1 to Stages 2 and 3 to distinguish all the compounds with results for all remaining compounds stated. Describing subsequent organic test on product (unnecessary) - limits to lower mark in level All stages are covered but stage(s) may be incomplete or may contain inaccuracies OR two stages are covered and are generally correct and virtually complete. Answer is communicated mainly coherently and shows a logical progression from Stage 1 to Stages 2 and 3. Describing subsequent organic test on product (unnecessary) - limits to lower mark in level Two stages are covered but stage(s) may be incomplete or may contain inaccuracies OR only one stage is covered but is generally correct and virtually complete. Answer includes isolated statements but these are not presented in a logical order. 0 mark Insufficient correct chemistry to gain a mark. 07.1 MARK SCHEMEA-LEVEL CHEMISTRY7405/2JUNE 2017 Indicative Chemistry content Stage 1: An initial test to separate into two groups (2 groups of 2 OR 1 group of 3 and 1 group of 1) Stage 2: An second test to distinguish within a group or to separate into two further groups Stage 3: A third test leads to a set of results/observations which distinguishes between all 4 compounds Tests must include reagent and observation which identifies compound(s) -COOH a) NaHCO3 / Na2CO3 (or correct alternative) b) effervescence /gas turns limewater milky c) K and /or M but not L and/or N -OH and -CHO d) acidified K2Cr2O7 e) solution turns green f) K and/or L and/or N but not M -CHO g) Fehlings OR Tollens h) red ppt OR silver mirror i) N only but not K and/or L and/or M -Br j) Silver nitrate k) cream ppt l) L and/or N but not K and/or M Isolated tests on individual compounds - max LEVEL 2 Isolated tests not linked to any compoundmax LEVEL 1 Penalise observation if deduction wrong, but allow observation if deduction incomplete 23 of 32<br />
MARK SCHEMEA-LEVEL CHEMISTRY7405/2JUNE 2017 Alternative tests -COOH a) named alcohol & H2SO4 b) sweet smell (of ester) c) K and /or M but not L and/or N -COOH a) named indicator b) correct colour c) K and /or M but not L and/or N -OH only m) named carboxylic acid & H2SO4 n) sweet smell (of ester) o) K and/or L but not M and /or N Test Tests for a) NaHCO3 / Mg / Indicator K M d) K2Cr2O7 / H+ K L N g) Fehlings / Tollens j) AgNO3 see Note * a) named alcohol & H2SO4 m) named carboxylic acid & H2SO4 L N K M K L Note * allow NaOH then HNO3, AgNO3 as one test; but treat NaOH, AgNO3 without acid as incomplete,so can mark on. 24 of 32<br />

Question 1 2 3 4 5 6 7 8 9 10 11

About us | Need Help? | Feedback

Proudly powered by WordPress | Theme: Sydney by aThemes.