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Version 2.0 Copyright © AQA and its licensors. All rights reserved. C3 3.4 Analysis and quantitative chemistry.

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Presentation on theme: "Version 2.0 Copyright © AQA and its licensors. All rights reserved. C3 3.4 Analysis and quantitative chemistry."— Presentation transcript:

1 Version 2.0 Copyright © AQA and its licensors. All rights reserved. C3 3.4 Analysis and quantitative chemistry

2 Using Exam pro items to support successful outcomes Version 2.0 Copyright © AQA and its licensors. All rights reserved. Learners will be able to test their progress against learning outcomes using questions from past AQA GCSE examinations C3 3.4

3 Foundation Tier QSP 3F 06 Version 2.0 Copyright © AQA and its licensors. All rights reserved. C3 3.4

4 Version 2.0 Copyright © AQA and its licensors. All rights reserved. C3 3.4

5 Version 2.0 Copyright © AQA and its licensors. All rights reserved. C3 3.4

6 Mark scheme- Foundation Version 2.0 Copyright © AQA and its licensors. All rights reserved. C3 3.4 Q 1AnswerExtra InformationMark (a) (i) fizzing / effervescing1 (a) (ii) cloudy / milky / white1 (b) white1 (c) (i) sodium chloride1 (c) (ii) potassium ions give a lilac flame colour potassium’s flame colour is masked by sodium’s flame colour 1111 Total6

7 2. Foundation Tier QSP 3F 09 Version 2.0 Copyright © AQA and its licensors. All rights reserved. C3 3.4

8 Version 2.0 Copyright © AQA and its licensors. All rights reserved. C3 3.4

9 Mark scheme- Foundation Version 2.0 Copyright © AQA and its licensors. All rights reserved. C3 3.4 Q 2AnswerExtra Information Mar k (a) Drain Buster is a concentrated sodium hydroxide solution that would damage the skin therefore it is diluted so that it is safe to use for the experiment 1111 (b) No relevant content.Marks awarded for this answer will be determined by the Quality of Written Communication (QWC) as well as the standard of the scientific response. 0 Level 1 There is a brief description of the titration that may include a risk assessment. examples of the chemistry points made in the response burette / acid / HCl used correctly pipette used for Drain Buster solution / alkali / NaOH correctly read meniscus at eye level acid / HCl added dropwise indicator used white background/tile end-point of titration recorded swirling/mixing repeat example of risk assessment points made in the response eg Wear safety goggles – to protect eyes because hydrochloric acid is corrosive / irritant and / or sodium hydroxide is caustic 1–2 Level 2 There is some description of the titration that may include a risk assessment. 3-4 Level 3 There is a clear, balanced and detailed description of the titration and an appropriate risk assessment. 5-6 Total8

10 Higher Tier QSP 3H 05 Version 2.0 Copyright © AQA and its licensors. All rights reserved. C3 3.4

11 Version 2.0 Copyright © AQA and its licensors. All rights reserved. C3 3.4

12 Version 2.0 Copyright © AQA and its licensors. All rights reserved. C3 3.4

13 Mark scheme- Higher Version 2.0 Copyright © AQA and its licensors. All rights reserved. C3 3.4 Q 1AnswerExtra InformationMark (a) sodium – yellow flame potassium – lilac flame potassium’s flame colour is masked by sodium’s flame colour (b) magnesium1 (c) (i) carbonate (ions) must be present because carbon dioxide was produced when nitric acid was added chloride (ions) must be present because a white precipitate formed when acidified silver nitrate solution was added 1111 (c)(ii)the student would make the same observations using either hydrochloric acid or nitric acid any conclusion would not be valid because hydrochloric acid contains chloride (ions) the explanation is that these chloride (ions) would cause a white precipitate without the presence of the low sodium salt / sodium chloride / potassium chloride Total9

14 Q2 Higher Tier QB0 3H 19 (a) Version 2.0 Copyright © AQA and its licensors. All rights reserved. C3 3.4

15 Version 2.0 Copyright © AQA and its licensors. All rights reserved. C3 3.4

16 Mark scheme- Higher Version 2.0 Copyright © AQA and its licensors. All rights reserved. C3 3.4 Q 2AnswerExtra InformationMark (a) (i) e.g. moles NaOH = moles of acid or formula: 0.2 × = M 1 = 0.2 × 45 M 1 = 0.6(M) ecf for arithmetical error correct answer 2 marks rounding to 0.01 loses mark = × = 0.6(M) 1111 (a) (ii) 36 ecf – (a)(i) × 60 relative formula mass of ethanoic acid = 60 for 1 mark correct answer 2 marks 0.6 × 60 gets 1 mark 0.6 × incorrect molar mass gains second mark only 1111 Total4

17 C3 3.4


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