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CIE Nov 2013 v1 Paper 4 Q7
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![Examiners For Use 14 Electrophoresis is a technique which can be used to separate amino acids or peptide fragments present in a mixture. (a) Draw a diagram to show the apparatus used to carry out electrophoresis. You should label each of the relevant parts of the apparatus. [4] (b) How far an amino acid will travel during electrophoresis depends on the pH of the solution. For a given potential difference, state two other factors that will affect how far a given amino acid travels in axed time during electrophoresis. 1.2.[2] (c) A number of analytical and separation techniques rely on substances having different partition coef cients. State what is meant by the term partition coef cient.[1]UCLES 2013 9701/41/O/N/13<br />
Examiners For Use (d) The partition coef cient of X between ethoxyethane and water is 40.0. A solution contains 4.00 g of X dissolved in 0.500 dm3 of water. 15 Calculate the mass of X that can be extracted from this aqueous solution by shaking it with (i) 0.050 dm3 of ethoxyethane, (ii) two successive portions of 0.025 dm3 of ethoxyethane.UCLES 2013 9701/41/O/N/13 [Turn over [4] [Total: 11]<br />](https://learnah.org/wp-content/uploads/2018/08/November_2013_v1_QP_-_Paper_4_CIE_Chemistry_A-level_7-0.jpg)
![Pa age e 9 ark k S Sch he yll ab bus Pa ape er ( (a) CE E A A L EV VEO Octo ob ber /N ove em mbe er 20 13 97 701 4 41 4 4[1 4] 2 2[1 2] [1 [1 [1 ecf e f [1 ecf e f [1 ecf e f [1 4] 11 [To ota al: p pow wer r su upp ply y (id dea a o of c com mp e elec ctro oly yte/ /bu uffe er s solu utio on let e c circ uit g gel/ /filt ter pa ape er/a abs sor rbe nt ap er mp ple/ /mi ixtu ur e [ cen ntre e of f p lat e] mino o a acid d) s sa ( (b) ) a any y tw wo fro om: s size e/M Mr ( (of the e a ami ino o ac cid pec cies s) e a am mino o a acid d s pe cie es) c cha arge e ( on th te e mpe era tur re ( (c) Rat tio of the e c con nce entr rati ion n o f a so olut te i ea ch of two o ( im mis sci ible e) sol ve nts or e o equ uilib briu um m co ons sta ant rep pr es ent ing g th he di strib but tion of a so olu ute be et wee en t two o solven nts b (a at a a c on st or P o PC [X] X] ]a/[X ant te mp per rat ure e) ( (d) ) ( (i) Kpc = K = [Z Z i n e eth er] ]/[Z Z in n H 2O O]al low w r ev ers se rat tio (i i) (ii i) 40 0 = = (x x/0 .05 5)/( ((4 x) )/0 .5 3. 2 g irst t ex xtr ract tion 40 0 = = (x x/0 .02 25) )/((4 4x x)/ /0. 5) = 2 2.6 67 ec con d e ext trac ctio on: 1. 3g rem mai in i in sol utio on ec con d e ext trac ctio on 40 0 = = (y y/0 .02 25) )/(( 1.3 33 y) /0. 5) = 0 0.8 887 7 g m mas ss e ext trac cte ed = = 2 2.67 + 0 .89 9 = = 3. .5 6/3 .6 g Ca amb bri dge e In nter rna tio nal Ex xam min ati ons s 20 013<br />](https://learnah.org/wp-content/uploads/2018/08/November_2013_v1_MS_-_Paper_4_CIE_Chemistry_A-level_7.jpg)