Acceptable Answers Reject Mark. Acceptable Answers Reject Mark. Acceptable Answers Reject Mark

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1 (a) Pale/light and green/yellow Allow (virtually) colourless clear yellow green any other colour (b)(i) (b)(ii) Red/brown (solution) Allow yellow Ignore (From.) to. Purple (or in combination with red or brown) Pale yellow Orange (or in combination with red or brown) Reject any other colours alone or in combination Grey/black (or any other colour alone or in combination) solid Cl (aq) + I (aq) Cl (aq) + I (aq)/(s) Entities () Balancing and all four state symbols Dependent on correct entities () Cl (aq) + KI(aq) KCl(aq) + I (aq)/(s) max K + (aq) on both sides of otherwise correct equation max (c)(i) Starch () Blue/black to colourless Dependent on starch indicator () Accept: no indicator needed () Yellow to colourless () Any other indicator e.g. methyl orange/ phenolphthalein = 0/ Colourless to blue/black Blue/black to clear Any mention of purple Blank for indicator and yellow to colourless max

2 (c)(ii) (ii) (vi) General comme Allow correct answers with no working in all parts N.B. Mark each part to mark scheme answer first then allow TE from earlier parts. Minimum correct to SF. Penalise SF for SF once only. But incorrect rounding e.g to 4.5 is penalised once separately as well. Penalise wrong units once only as well. (Mean titre = 9.05) 9.05 x = 9.05 x 0 5 / (mol) 9.(0) x 0 5 / (0) Allow 9. x 0-5 / (mol) (c)(iii) (I (aq) + S O (aq) ) I ((aq)) + S 4 O 6 ((aq)) () () Marks stand alone for entities with balancing Either of these on their own scores mark regardless of anything else that is written Multiples/fractions of equation allowed Ignore state symbols even if incorrect (c)(iv) 9.05 x 0 5 = 4.55 x 0 5 / (mol) Allow 4.5 x 0 5 / etc Allow TE ans (ii) Accept TE from (iii) if you see it

3 (c)(v) (c)(vi) 4.55 x 0 5 / (mol) Allow TE = ans (iv) [Allow ans (iv) with no numbers for this part only] 4.55 x 0 5 x 000 = /4.5 x 0 / / (mol dm ) Accept TE ans (v) x 00 [a calculated number must be given] (d)(i) (d)(ii) (e)(i) (e)(ii) Lilac Allow (light) purple or mauve Violet Reject any other colours alone or in combination K + Cl KCl Accept multiples/fractions Ignore state symbols even if incorrect Ignore correct charges on ions in KCl K and/or KCl Charges on reactants K and/or Cl Hydrogen chloride This may be accompanied by HCl Hydrochloric acid HCl /HCl(g)/HCl (gas) alone SO H S Anything else Dissolves in moisture/water/water vapour (in the air) Or reacts with moisture/water/water vapour (in the air) HCl condenses

4 (e)(iii) NH 4 Cl / Ammonium chloride/ ClNH 4 Ammonia chloride / NH Cl NH + 4 Cl - / H 4 N + Cl - / Cl - + NH 4 Ignore any states even if incorrect (f)(i) Any one of: Phosphorus(V) chloride/pentachloride Phosphorus(III) chloride/trichloride Allow (III/V) anywhere Phosphorus chloride Concentrated hydrochloric acid Hydrogen chloride (gas) Sodium/potassium chloride and concentrated sulfuric acid Thionyl chloride Hydrochloric acid/hcl/ HCl(aq) Chlorine Allow correct formula(e) for all above But note: conc HCl /conc H SO 4

5 (f)(ii) Be generous here Sealed apparatus but ignore inadvertent closures owing to poor cross-sectional drawings (-) Horizontal test tube with ceramic fibre/ any sort of wool except iron () soaked in -chlorobutane and (alcoholic) potassium hydroxide/reactants/ reagents/ chemicals/reaction mixture with heat (or any diagram of a heat source or the word heat) () Round bottom/pear shaped flask/sloping test/boiling tube and heat (or any diagram of a heat source or the word heat) () containing -chlorobutane and (alcoholic) potassium hydroxide/reactants/ reagents/ chemicals/reaction mixture () Ignore: Poor diagram e.g. clear air gaps at intermediate joints in the apparatus(-) Solution/substances alone An arrow on its own Conical/flat bottomed flask N.B. contradiction between drawing and any label Solution/substances alone any use of aluminium oxide/pumice reflux/distillation set up Gas collection over water () Ignore Bunsen valves Allow: A poor diagram mark (which can be the second) should be deducted for the delivery tube through the side of trough and/or the delivery tube missing the collection tube. Collection in a gas syringe Note: This does not constitute a sealed apparatus

6 (a) Mark independently From: colourless () To: pink / (pale) red () If colour change wrong way round max () From: clear To: magenta / purple / cerise (b (Titres, and 4) are concordant / within 0. (cm ) / within 0. (cm ) / consistent Titre is rough / trial / a rangefinder / too far out / overshot ALLOW Titre is an outlier / is anomalous Just very similar / within 0.05 / within 0.5 Titre very different Just not accurate Titration is a control experiment (c) 8.00 (cm ) / 8.0 (cm ) / 8 (cm ) 8.4 (cm ) / 8. (cm ) / 8. (cm )

7 (d)(i) 0.00 x 8.00 = /.8 x 0 - (mol) 000 ALLOW TE from (c) IGNE sf except one sf (d)(ii) /.8 x 0 - (mol) Same answer to (d)(i) if TE applied IGNE sf except one sf (d)(iii) = 0. (mol dm - ) 0.05 Answer to (d)(ii) if TE applied from (d)(ii) 0.05 IGNE sf except one sf (d)(iv) 0 x 0. =. (mol dm - ) Answer to (d)(iii) x 0 if TE applied from (d)(iii) IGNE sf except one sf

8 (d)(v). x 60 = 67. (g dm - ) 67. Answer to (d)(iv) x 60 if TE applied from (d)(iv) IGNE sf except one sf

9 (e) NOTE: answer must refer to making up the diluted solution and not the titration NOTE: the Reason mark must be correctly linked to the Improvement Improvement: Use a pipette / burette to measure acid (solution) () Reason: Pipette / burette more accurate (than a measuring cylinder) () Use of volumetric flask for initial measurement of volume of vinegar solution more reliable ALLOW more precise Improvement: Shake / invert the volumetric flask (thoroughly) () Reason: To ensure a uniform concentration () Improvement: Rinse out measuring cylinder (and transfer washings to the volumetric flask) () swirl (the flask) to ensure fully dissolved just rinse out apparatus Reason: To ensure all the acid is transferred (to the volumetric flask) () Improvement: Use a (teat) pipette to make up to the mark (in volumetric flask) () Reason: To ensure volume of solution accurately measured () Any suggested improvements relating to the titration part of this experiment

10 (f)(i) Z / between 7.85 and 8.05 (cm ) ALLOW 7.95 ±0.0 (cm ) (f)(ii) Any one of the following / a statement equivalent to: overshoots/misses end-point water left in burette / pipette air lock below tap in burette / air in pipette burette not vertical alkali not at stated concentration leaking tap not reading meniscus at eye-level funnel left in top of burette not reading level against a white background not reading meniscus correctly washing pipette between titres washing the flask with the solution that will go in it not swirling flask / mixture water left in conical flask just measurements may be inaccurate there could be uncertainty with other equipment contamination of the vinegar IGNE errors in calculation

11 7 (a) (i) Al(s) + OH (aq) +H O(l) AlO (aq) + H (g) 0 - (aq) (a)(ii) x 0 = 0.0 / x Ignore trailing zeroes (a)(iii) 0.0 / x 0 Accept TE answer to (ii) (a)(iv) 0.0 x 7.0 = 0.54 / 5.4 x 0 (g) TE answer to (iii) (ii) x 7.0 Other unit Ignore sf except (a)(v) (. x 0.54) = 0.59(4) / 5.9(4) x 0 (g) TE answer to (iv) x. Ignore sf except Only penalise sf once

12 (a)(vi) Potassium hydroxide / KOH (solution) is corrosive / burns / caustic KOH damages / harms / is harmful to / dissolves / reacts with skin / eye(s) () Toxic, carcinogenic, alone or in combination with correct answer KOH in eye(s) () Ignore Harmful, irritant, highly reactive alone Hydrogen / H is flammable / explodes / explosive () Allow mention of both potassium hydroxide and hydrogen alone scores () Allow Al foil can cut your skin () Burns alone Additional chemicals Correct answer with additional incorrect chemistry e.g. KOH is oxidising so corrosive scores (0) (b)(i) (b)(ii) KAlO (aq) + H SO 4 (aq) KAl(SO 4 ) (aq) + H O(l) Allow multiples x 000 x 0.0 =40 (cm ) Allow 0.04(0) dm TE answer to (a)(ii) x 000 and TE from (b)(i)

13 Litmus (paper / solution) () (b)(iii) Red / pink (in acid) any other named acid-base indicator including universal indicator () with a correct acidic colour () () NB phenolphthalein must be spelt correctly to score () and no mark for colour Notice that other indicators only require recognisable spellings Red litmus turns blue scores for the indicator ph meter / universal indicator () with value < 7 () NB measure ph alone (0) ph < 7 () add a (metal) carbonate / suitable metal eg Mg () bubbles / fizzing () Calculation of amounts / moles of both reactants ( maximum) ()

14 (b)(iv) Each point must be made in full The second and final scoring points, which are asterisked, can only be gained through these statements. Two further marks can be scored for any two of the other four points. 4 Filter (to remove any aluminium / impurities) () NB This mark can only be awarded if it is the first action and the mixture is subsequently heated. *Boil / heat / evaporate to reduce the volume of water () NB boil / heat to remove water only gets the mark if it is clear, subsequently, that some solution is left Cool / set aside / leave to allow crystals to form () Leave in the sun If boiled to dry stop marking here 4 Filter pick out / remove / take out crystals (to separate) 5 Wash with a little/cold water () () Heat in oven 6 *Place between filter papers / dab with paper towel / use dessicator (to dry) () (b)(v) White / colourless Ignore clear / transparent / cloudy / opaque e.g. accept clear and colourless Any other colours with or without white

15 (b)(vi) Cr + / Fe + / Sc + / Ga + Accept any feasible triply positive metal ion Allow B + Al + and anything else Allow any name or symbol for a Group element Allow named existing transition metal ions with (III) after the name (if they exist) Group element with incorrect charge Fully correct formula for an alum or intermediate starting entity Eg KGa(SO 4 ) / KGaO

16 4 (a) All have the same number of electrons / all have one (s) electron / same electron All have one p electron configuration () All have the same number of protons / all have one proton () The first has no neutrons, the second one neutron and the third two neutrons Allow deuterium has one more neutron, tritium two more neutrons () Different number of neutrons alone Ignore references to same atomic number and different mass numbers 4 (b) ( + +) s can be on either side or both sides 4 (c)(i) Molar mass / M(r) / + / + = 5 (g mol ) () of moles = 4/5 = 0.8 () O.8 with correct working, with wrong working, or with no working Allow internal TE if Molar mass clearly indicated and incorrect eg Molar mass / M(r) = 6 (g mol ) (0) of moles = 4/6 = 0.67 () () Penalise incorrect units

17 4 (c)(ii) x 0.8 = 9 00 (cm ) Incorrect units Allow 9. dm Allow TE from (c)(i) 4 (d).0078 x x x x () Notice this working must be shown in full to score first mark. (=.00795) =.0080 ().008 max with or without working Incorrect units e.g. Correct answer no working () Only give second mark for correct answer to 4 decimal places Ignore g mol - 4 (e)(i) Single arrow upwards from lowest line to infinity line (allow above or very close below) Allow double headed arrow More than one line

18 4 (e)(ii) Hydrogen s and Sodium s s p 6 s Electron numbers may be on lines or subscript. () Both have one (s) electron in the outer shell / orbital / sub shell same number of electrons / same electron(ic) configuration in outer shell / orbital / sub shell s s half filled s outer shell same electron(ic) configuration alone Both have an/one unpaired electron in their outer / last shell / orbital / sub shell () Second mark depends on one outer shell s electron shown for each electronic configuration 4 (f) Helium Any two from the following points: () Any other elements Electron removed is closest / close to the nucleus () Little shielding, allow no shielding () More protons / higher nuclear charge than hydrogen. Allow higher effective nuclear charge () NB second and third marks can be gained if hydrogen is given: Electron removed is close / closest to the nucleus () No shielding ()

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