Skip to content
CIE Jun 2016 v3 Paper 4 Q2
Answers available below
Show answer
Question
1
2
3
4
5
6
7
8
9
10
![(a) (i) Complete the following electronic configurations. the cobalt atom, Co 1s22s22p6the cobalt(II) ion, Co2+ 1s22s22p6PMT [1] (ii) State the colours you would observe when concentrated HCl (aq) is added to an aqueous solution of cobalt(II) nitrate, Co(NO3)2. Give the formulae and geometry of the complexes formed.[5] (b) There are two isomers with the formula Ni(R3P)2I2, but only one structure with the formula Co(R3P)2I2. (R = alkyl, R3P is a monodentate ligand) Draw diagrams showing the structure of Co(R3P)2I2 and the two isomers of Ni(R3P)2I2. Ni(R3P)2I2 Ni(R3P)2I2 Co(R3P)2I2UCLES 2016 9701/43/M/J/16 [3] [Total: 9] [Turn over<br />](https://learnah.org/wp-content/uploads/2018/08/June_2016_v3_QP_-_Paper_4_CIE_Chemistry_A-level_2.jpg)
![Page 2 Mark Scheme Syllabus Paper Cambridge International AS/A LevelMay/June 2016 9701 43 PMT Answer Marks [1] [1] [1] [1] [1] [1] [1] [1] [1] [Total: 9] [1] [1] [1] [1] [1] [1] Question (a) (i) Ca(OH)2 + CO2CaCO3 + H2O (ii) Ba(OH)2 is soluble, OR BaCO3 is insoluble (iii) Mg(OH)2 is insoluble / not very soluble will not form ppt. of MgCO3 (b) carbonates are more stable down the group due to increase in cationic size / radius (causing) less polarisation of CO3 2 ion (c) radius of Ni 2+ = 0.070 nm; radius of Ca 2+ = 0.099 nm so NiCO3 decomposes more readily than CaCO3 (a) (i) Co: 3s 3p 3d 4s Co 2+ 3s 3p 3d (ii) solution starts pink turns blue pink is [Co(H2O)6] blue is [CoCl 2 4] 2+ this complex is tetrahedralCambridge International Examinations 2016<br />
Page 3 Mark Scheme Syllabus Paper Cambridge International AS/A LevelMay/June 2016 9701 43 PMT Question (b) Ni Answer Ni PR Co PR (a) p = {p(CS2)(p(H2)) units: atm OR Pa } / {(p(H2S))p(CH4)} (b) (i) p(H2S) = 196 atm = 8 atm p(H2) (ii) K p = (28 ) / (19698) = 2.17610 3 (c) (i) S will be positive, because more gas moles on the RHS / products (ii) S = (H kJ mol 1 1G OR J mol 1 1 ) / T = (24151)/1000 = 0.19 OR 190 (d) G will become less positive/more negative as T increases, is positive (or T S because S is more negative) therefore the reaction becomes more feasible / spontaneous as T increases Marks [1] [1] [1] [Total: 9] [1] [1] [1] [1] [1] [1] [1] [1] [2] [Total: 10]Cambridge International Examinations 2016<br />](https://learnah.org/wp-content/uploads/2018/08/June_2016_v3_MS_-_Paper_4_CIE_Chemistry_A-level_2-0.jpg)
