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Edexcel Jun 2013 (R) Paper 1 Q23
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![Question Number 23(b)(i) C10H22 + 10O210CO + 11H2O Acceptable Answers ALLOW 21 / 2 O2 ALLOW any correct multiples IGNORE state symbols, even if incorrect Acceptable Answers Question Number 23(b)(ii) Any statement that makes it clear there is not enough air or oxygen e.g. Limited supply of air / limited supply of oxygen / not enough air / not enough oxygen / lack of oxygen / little amount of oxygen/ small amount of oxygen IGNORE it is not completely oxidized Question Number 23(a) Acceptable Answers CnH2n+2 IGNORE where n=1, 2, 3 etc or where n is greater than 1 Reject Reject 21 [O] Reject Mark Mark Mark 6CH0101R 1306<br />
Reject Mark Question Number 23(c) Acceptable Answers First mark Dative pair of e- between S and right- hand O (1) Second mark Two bond pairs between S and left- hand O (1) Third mark Two lone pairs on left-hand O, one lone pair on central S and three lone pairs on right-hand O atom (1) If 2 double bonds between sulfur and each oxygen then the third mark can be given for two lone pairs on both oxygens and one lone pair on central S O S O X X X X NOTE ALLOW dots and crosses that have been reversed Lone pair electrons can be shown as separated (rather than having to be paired up)it is the total number of electrons in each outer shell that matters Stand alone marks If molecule shown as charged then 2 max 6CH0101R 1306<br />
Question Number 23(d)(i) Acceptable Answers Reject CH3 CH3 Mark CH3 Mark Mark 6CH0101R 1306 Question Number 23(d)(ii) C7H16C7H14 + H2 Acceptable Answers ALLOW C6H11CH3 IGNORE state symbols, even if incorrect benzene ring Reject Formulae other than molecular formulae Any other structural or displayed formulae Question Number 23(d) (iii) Acceptable Answers Reject Less pollution / reduce waste High atom economy Produces useful products / hydrogen Used to make polymers Produces substances in higher demand / more valuable Any ONE of: (a cyclic alkane) has more efficient combustion allows smoother burning increases octane number reduces knocking / less likely to produce pre-ignition is a more efficient fuel burns better / easier to burn /combusts more easily / improves combustion IGNORE (a cyclic alkane): increases the volatility of a fuel ignites more easily is a better fuel burns more cleanly IGNORE (a cyclic alkane) has a lower boiling point mentions of viscosity safer fuel<br />
Question Number 23(e)(i) Question Number 23(e)(ii) Acceptable Answers Reject 2,2-dimethylpentane IGNORE missing hyphen/missing comma 2-dimethylpentane Acceptable Answers Reject (1) (1) IGNORE names even if incorrect IGNORE different length bonds IGNORE direction of methyl groups Acceptable Answers U.V. / U.V.light / light / sunlight ALLOW high temperature Question Number 23(f)(i) Question Number 23(f)(ii) Cl2Cl + Cl / Acceptable Answers Cl22Cl IGNORE any curly arrows, even if incorrect IGNORE C4H10 given on both sides Reject heat alone Reject Mark Mark Mark Mark 6CH0101R 1306<br />
Question Number 23(f)(iii) Homolytic (fission) Acceptable Answers IGNORE any formulae and arrows Question Number 23(f)(iv) (First propagation step) Acceptable Answers C4H10 + ClC4H9 + HCl (1) (Second propagation step) C4H9 + Cl2C4H9Cl + Cl (1) Formulae can be displayed dots can be anywhere on free radical but no dots at all scores zero ALLOW in either order Incorrect alkane / halogenoalkane but two correct propagation steps scores 1 out of 2 Question Number 23(f)(v) Any ONE of: Acceptable Answers Mark Mark Reject Photolysis (fission) / free radical (fission) Reject Any reactions involving Hydrogen radicals scores zero Reverse of first reaction Reject Mark C4H9 + ClC4H9Cl OR Cl + ClCl2 OR C4H9 + C4H9C8H18 Total for Question 23 = 18 marks 6CH0101R 1306<br />](https://learnah.org/wp-content/uploads/2018/08/June_2013_R_MS_-_Unit_1_Edexcel_Chemistry_A-level_23-0.jpg)
