Mark Scheme (Results) June 2010

Transcription

1 Scheme (Resuls) June 00 GCE GCE Chemisry (6CH07/0) Edexcel Limied. Regisered in England and Wales No Regisered Office: One90 High Holborn, London WCV 7BH

2 Edexcel is one of he leading examining and awarding bodies in he UK and hroughou he world. We provide a wide range of qualificaions including academic, vocaional, occupaional and specific programmes for employers. Through a nework of UK and overseas offices, Edexcel s cenres receive he suppor hey need o help hem deliver heir educaion and raining programmes o learners. For furher informaion, please call our GCE line on , our GCSE eam on , or visi our websie a If you have any subjec specific quesions abou he conen of his Scheme ha require he help of a subjec specialis, you may find our Ask The Exper service helpful. Ask The Exper can be accessed online a he following link: hp:// Alernaively, you can speak direcly o a subjec specialis a Edexcel on our dedicaed Science elephone line: Summer 00 Publicaions Code US03643 All he maerial in his publicaion is copyrigh Edexcel Ld 00 6CH07_0 006

3 Accepable Answers Rejec (a)(i) Nichrome wire / plainum wire / ceramic / silica rod () Accep recognisable spelling eg plainium, nickrome (Concenraed /dilue) hydrochloric acid/ H Cl/HCl(aq) / soluion () Sal (mixed wih wire and acid, and) placed in a ho/blue/roaring/non-luminous/bunsen/bunsen burne r flame () Tianium, aluminium, nickel, chromium, copper, silicon Sal placed in Bunsen burner flame alo ne burn i 3 Accepable Answers Rejec (a)(ii) Li + Accep li + / Li + ions/ A is Li + Ignore (aq), (s), (l), (g) Li, Li +,Ca, Sr, Rb Ca +, Sr +, Rb + Lihiu m/ lihiu m ions ( b)(i) Calcium hydroxide/ca(oh) / slaked lime Calcium/Ca Accep calcium oxide/cao / quicklime CO /CaCO 3 Ignore (aq) / soluion / (s) / solid 6CH07_0 006

4 Accepable Answers Rejec (b)(ii) CO / HCO 3 () Ignore separaed addiional caion CO3, CO 3, carbonae, hydrogencarbo nae Li CO 3, LiHCO 3, CaCO 3 ec Carbon dioxide gas given off (when his carbonae /hydrogencarbonae is heaed/decomposed) () Second mark depends on a recognisable carbonae/hydrogencarbonae ie CO 3, CO 3 -, carbonae, hydrogencarbonae Li CO 3, LiHCO 3, CaCO 3 ec (c)(i) Oxide / O - Oxygen, O, O, O - calcium oxide / CaO (c)(ii) Hydroxide / OH - /(OH - ) (OH) - 6CH07_0 006

5 Accepable Answers Rejec (c)(iii) wih reference o (ii) For correc answer o (ii) Universal indicaor (paper) () Tu rns blue/purple/ph-4 () Accep oher appropriae indicaors eg (red) limus (paper) urns blue Add a suiable meal ion soluion () o giv e a correc colour of precipiae () [see User Guide page 7 for some deails] Warm / hea wih ammonium ions () Alkaline gas given off/damp red limus urns blue/ ammonia gas given off () Oher reasonable ess wih resuls eg Tirae wih hydrochloric acid and suiable indicaor wih correc final colour If incorrec answer o (ii) bu answer as above () max If incorrec answer o (ii) wih correc es and correc resul for ha ion () max Accepable Answers Rejec (d) Li CO 3 Accep Li (CO 3 ) LiHCO 3 LiCO 3 Accep correc formula of any red flame coloured s block meal carbonae/hydrogencarbonae eg Rb CO 3, CaCO 3, SrCO 3 6CH07_0 006

6 Accepable Answers Rejec (a)(i) Silver((I))iodide (solid / precipiae) / AgI / Ag + I - /AgI(s) Silver((I))iodide (solid / precipiae) and AgI / + - Ag I / AgI(s) Iodide (alone) Iodine Silver ((I)) iodine AgBr and AgI Cl - /Br - /I - If boh name and formula are given and eiher is wrong eg Silver((I)) Iodine and AgI (a)(ii) C 3 H 7I (in any order) Accep addiional informaion like addiional formulae Any answer which does no have C 3 H 7 I somewhere (a)(iii) H H H H- C C C -H H I H Displayed or srucural formula for - iodopropane Accep srucural formula CH 3 CHICH 3 6CH07_0 006

7 (a)(iv) A firs ignore answer o (iii) Propan--ol / -propanol / CH 3 CH(OH)CH 3 Accep displayed formula (allow slighly displaced bonds C) HO Propanol prop--ol C 3 H 7 OH Accep skeleal formula Allow TE from (a)(iii) eg -iodopropane forms propan--ol (b)(i) colours independenly From orange () yellow To green/blue () Accep shades of green eg dark green, muddy green, green-brown (b)(ii) Propanone prop((--))one Accep propan--one Allow propanal/propanoic acid if TE from (a)(iv) (b)(iii) Oxidaion / redox / oxidaion and reducion / oxidaion of (eg alcohol) Reducion Condensaion/ subsiuion/ Addiion 6CH07_0 006

8 Accepable Answers Rejec 3 (a)(i) (Glass/graduaed/volumeric/bulb)pipee (and pipee filler) Accep any recognisable spelling of pipee eg pipe, pipee ec Buree/ pipee and buree/ measuring cylinder/ ea pipee/ dropping pipee Pipae/pipoe Accepable Answers Reje c 3 (a)(ii) Sarch (soluion) () Accep sarch Oher indica ors eg Mehyl orange /phenolph- halein Blue-black/blue/black o colourless () Accep purple/blue-black o colourless Second mark depends on firs Colourless o blueblack/ blue/ black 3 (b)(i) 4.5(0), 3.7(0), 3.75 All hree needed for he mark 6CH07_0 006

9 3 (b)(ii) The firs resul is discarded/ ignored/ no included/a range finder Only use las wo values The second and hird are concordan / firs value no wihin 0. cm 3 Accep: This is he average of he second and hird runs Acual correc average calculaion o give 3.73/ (b)(iii) 3.73 x =.746 x 0-4 / (mol) 000 sf Accep.7/.75 x 0-4 Noe ha 3.75 gives.745 x 0-4 Allow TE from differen calculaed average ire 3 (c).373 x0-4 / (mol) Also.35/.37/.375 /.4 x 0-4 Accep answer o (b)(iii) sf (unless already penalised anywhere in his quesion) 6CH07_0 006

10 Accepable Answers Rejec 3 (d) 4.58 x 0-5 / (mol) /4.577 x 0-5 ec Also 4.583/4.57/4.6(0) x 0-5 Accep answer o (c) 3 sf (unless already penalised anywhere in his quesion) Accepable Answers Rejec 3 (e)(i) Vo lumeric/graduaed (flask) (00 cm 3 ) round boomed flask/ conical flask/ measuring cylinder 3 (e)(ii) These marks are independen of flask used in (i) 3 Transfer soluion and rinsings/washings () Ma ke up o he mark () Make sure i is all ransferred Mixin g / invering / shaking (his mus be a he end) ( ) 3 (e)(iii) 4.58 x 0 / (mol) Also 4.57/4.6 x 0-4 Accep Answer o (d) x 0 sf (unless already penalised anywhere in his quesion) 6CH07_0 006

11 3 (e)(iv) 4.58 x 0 x 4 = /0.980 g -4 Also / ec Accep answer o (e)(iii) x 4 Ignor e SF sf (unless already penalised anywhere in his quesion) 3 (e)(v) x = 98 /98.0/98.0/98.0 % Also 97.94/97.94/97.9 % Accep answer o (e)(iii) x correc answer wih no working scores () Ignore SF sf ( unless already penalised anywhere in his quesion) 3 (f) Sulfuric acid is corrosive/irrian/irriable/burns (skin) Sulfuric acid is harmful/ hazardous/ oxic 6CH07_0 006

12 Accepable Answers Rejec 4 (a)(i) From he equaion mol buan--ol gives mol of -bromobuane / raio : OWTTE () As 80% yield, 0.5 mol of buan--ol gives 0.5 x 0.8 mol = 0. mol of -brombuane () Accep any clear indicaion ha hey appreciae he proporion calculaion and he mole raio Examples: of moles of buan--ol = 0. x 00 / (= 0.5) of moles of -bromobuane = 80 x (= 0.) In boh hese examples buan--ol / -bromobuane as appropriae, mus be presen o gain () The numerical expression alone would gain () As above examples bu addiionally using molar masses o calculae masses 4 (a)(ii) 74 x 0.5 () = 9.5 ( g) 9. 5 =.4 /.4/.40/ cm () sf ie ignore sf unless only one Accep.4 /.4/.40/ cm 3 () (wih no working) 6CH07_0 006

13 4 (a)(iii) 0.5 x 9 = /4.87/4.88/4.9/5 (g) sf 4 (b) Flask in beaker of labelled cold waer () Waer need no be drawn in bu Condenser wih jacke () Need no be labelled, can be a any angle so long as i goes upwards Condenser inle and oule wih correc waer direcion () This mark can be given if no jacke is presen open a op and no leaks() This mark is condiional on a condenser Do no penalise accidenal closures in drawing or aemps o draw ou perimeer of apparaus making he condenser appear closed If disillaion se up is drawn he beaker of cold waer mark can be awarded heaed beaker (of cold waer) sopper in he op/ap funnel in he op of he condenser unless clearly open 4 6CH07_0 006

14 Accepable Answers Rejec 4 (c)(i) Lower layer as more dense Lower layer is -bromobuane because i is denser Lower layer as denser han waer / buan--ol 4 (c)(ii) To remove / neuralize / reac wih remaining hydrochloric acid/hcl/acid/sulfuric acid/h SO 4 () by reacing o form carbon dioxide (gas) () 4 (d)(i) Disillaion /fracional dis illaion /redisil /disil /disillae Accep any recognisable spelling Ignore furher descripion Allow a descripion which includes he words heaing / boiling followed by condensing Dry/filer/ or anyhing else 4 (d)(ii) Measure boiling emperaure of liquid {and compare wih Daa Book value (0.7 o C) (Pu re if i agrees)} Boils a boiling emperaure of liquid/ 0.7 o C / boils over a very small emperaure range/ boils a one paricular emperaure Collec he produc a 0.7 o C/ beween 00 and 03 o C 6CH07_0 006

15 Furher copies of his publicaion are available from Edexcel Publicaions, Adamsway, Mansfield, Nos, NG8 4FN Telephone Fax Order Code US03643 Summer 00 For more informaion on Edexcel qualificaions, please visi Edexcel Limied. Regisered in England and Wales no Regisered Office: One90 High Holborn, London, WCV 7BH 6CH07_0 006