AQA A2 Chemistry C20 Electrode And Electrochemical Cell

This page contains the AQA A2 Electrode And Electrochemical Cells  Questions and kerboodle answers for revision and understanding .This page also contains the link to the notes and video for the revision of this topic.
 
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C20.1 Electrode potentials and the electrochemical seriesAQA  A2 Chemistry C20 Electrode And Electrochemical Cells: Page No. 51

1 a Ni(s)INi2+(aq) II Ag+(aq)IAg(s) E =+ 1.05 V b Electrons would flow from the nickel electrode to the silver electrode. Ni(s) -+ Ni2+(aq) + 2e Ag~(aq) + c–+ Ag(s) Overall: Ni(s) + 2Ag+(aq) -+ Ni2+(aq) + 2Ag(s) 2 @ a +0.63 V b -0.63 V.

20.2 Predicting the direction of redox reactions AQA  A2 Chemistry C20 Electrode And Electrochemical Cells : Page No. 55

1 0.90 V zinc electrode positive 2 @ a +0.93 v b -0.53 v c +0.97 v d +0.26 v 3 Chlorine and bromine, but not iodine.   4.a no b no

20.3 Electrochemical cells AQA  A2 Chemistry C20 Electrode And Electrochemical Cells : Page No. 59

1 List the advantages and disadvantages of each cell, described with regard to cost, practicaiity, safety, and the environment. Banner 2

Practice questions: Page No. 60-61

1 (a) (b) 1.23 V (c) Pt|H2(g)|OH–(aq),H2O(l)||O2(g)|H2O(l),OH–(aq)|Pt Correct but with Pt missing Includes Pt with correct representation (d) © Uses O2 + 2H2O + 4e– → 4OH And (2x) 2OH− + H2 → 2H2O + 2e– 2H2 + O2 → 2H2O (e) Increases the surface area (so reaction faster) (f) Overall reaction is the same (2H2 + O2 → 2H2O) (g) Hydrogen and oxygen supplied continuously OR Can be operated without stopping to recharge (h) Hydrogen may need to be made using an energy source that is not ‘carbon neutral’ 2 (a) Zn (b) From the table above select (i) Fe2+ (ii)) Cl2 (c) . (i) The standard electrode potential: 1.25 V (ii) Tl3+ + 2Fe2+ → 2Fe3++ Tl+ 3 (a) Pt|H2|H+||Fe2+|Fe Note, allow one mark only for correct symbol in reverse: Fe|Fe2+||H+|H2|Pt (b) Electron donor (c) Cl2 / chlorine (Species on RHS / electron donor) has most positive / largest Eo / has highest potential (d) (i) Cl / chlorine (ii) Chlorine +1 to chlorine 0 (e)
4HOCl + 4H+ + 4OH–→ 2Cl2 + O2 + 6H2O OR 4HOCl → 2Cl2 + O2 + 2H2O
f © e.m.f. = 0.40 – (–1.25) = 1.65 V / +1.65 V. Banner 3 DISCLAIMER Disclaimer: I have tried by level best to provide the answers and video explanations to the best of my knowledge. All the answers and notes are written by me and if there is any similarity in the content then it is purely coincidental. But this is not an alternative to the textbook. You should cover the specification or the textbook thoroughly. This is the quick revision to help you cover the gist of everything. In case you spot any errors then do let us know and we will rectify it. References: BBC Bitesize AQA GCSE Science Kerboodle textbook Wikipedia Wikimedia Commons Join Our Free Facebook Group : Get A* in GCSE and A LEVEL Science and Maths by Mahima Laroyia: https://www.facebook.com/groups/expertguidance.co.uk/ For Free Tips, advice and Maths and Science Help