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Edexcel Jun 2010 Paper 2 Q22
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![SECTION C Question Number 22(a)(i) Question Number 22(a)(ii) Question Number 22(a)(iii) Acceptable Answers Reject Mark 2-bromo-2-chloro-1,1,1-trifluoroethane ALLOW 1-bromo-1-chloro-2,2,2-trifluoroethane IGNORE incorrect punctuation and incorrect order of the halogen atoms 1-bromo-1- chloro-2- trifluoroethane Acceptable Answers Reject Mark London (forces) / instantaneous dipole / induced dipole / dispersion / van der Waals (forces) (1) permanent dipole (-permanent dipole) (forces) / dipole-dipole (forces) / dipole (forces) (1) IGNORE any references to hydrogen bonding Acceptable Answers Reject Mark Compound X is flammable Just to prevent an explosion Just to minimise the risk Any one of the following / a statement equivalent to: Ethanol is flammable [Note: if any reference to only the halogenoalkane being flammable scores (0)] OR reference to greater control of heating (e.g. to control the rate of reaction / to prevent the reaction being too vigorous / to prevent the reaction getting out of control) ALLOW so that the reaction takes place slowly OR (reaction) mixture is flammable/it is flammable OR Bunsen flame too hot / too vigorous OR (Bunsen flame) would cause too much evaporation to occur OR (allows) constant heating/ even heating 6CH0201 1006<br />
Question Number 22(a)(iv) Question Number 22(a)(v) Question Number 22(a)(vi) Acceptable Answers Reject Mark Solvent (for both reactants) OR To dissolve (the reactants) OR To mix the reactants ALLOW To enable the mixture to dissolve Just mixing to acidify the silver nitrate Acceptable Answers Reject Mark Cream / off-white / pale-yellow precipitate ALLOW Cream / off-white / pale-yellow solid IGNORE incorrect identification of this precipitate NOTE: both colour and state (of the AgBr) needed Just Yellow (precipitate/ solid) OR white precipitate OR white-yellow precipitate (0) if contradictory observation given, eg cream precipitate and fizzing Acceptable Answers Reject Mark Ag+(aq) + Br (aq)AgBr(s) Must include state symbols ACCEPT multiples If NO3 either sideleft on 6CH0201 1006<br />
Question Number 22(b)(i) Question Number 22(b)(ii) Acceptable Answers Reject Mark Mark independently Name: ethanol (1) ALLOW ethan-1-ol Structural formula: CH3CH2OH or C2H5OH (1) Allow displayed formula ALLOW brackets around the OH C2H6O Acceptable Answers Reject Mark Mark independently 1st mark: Energy of products, labelled, below that of reactants, labelled (1) Note if the words reactants and products are written, ignore any formulae Note if the words reactants and products are not written, both formulae of the reactants and both formulae of the products must be given. (Na+ ions can be omitted.) 2nd mark: Shape of profile with one hump (1) 3rd mark: Activation energy / Ea correctly shown with a single-headed arrow to the peak (or close to it) (1) Maxwell- Boltzmann curve scores (0) for (b)(ii) Double- headed arrow showing Ea 6CH0201 1006<br />
Question Number 22(c)(i) Question Number 22(c)(ii) Acceptable Answers Reject Mark Chlorofluorocarbon Accept flouro spelling Acceptable Answers Reject Mark Any one of the following / a statement equivalent to: aerosol / propellant / spray cans OR (degreasing) solvent OR fire retardant ALLOW fire extinguishers / putting out fires ALLOW making expanded polystyrene / making plastics / making polymers pesticides / anaesthetics just retardant anti-freeze air- conditioning frying pans detergents 6CH0201 1006<br />
Question Number 22(c)(iii) QWC Acceptable Answers Reject Mark Mark independently 1st mark: O + O32O2 IGNORE any state symbols (1) 2nd mark: (chlorine free radical acts as a) catalyst (1) Last 3 marks: any three from: (the chlorine free radical) persists in the atmosphere / continues to attack / is regenerated / (starts) a chain reaction (1) NOTE chain reaction may be described in terms of a chlorine radical breaking down many / a large number of / a specified number of, eg 10,000, O3 (molecules). NOTE: As written, this response also earns the scoring point relating to ozone depletion.causes (skin) cancer/mutation / DNA damage occurs (1) IGNORE any references to global warming / Greenhouse Effect less ozone / ozone decreases / causes hole(s) in ozone layer / breakdown of ozone (layer) / damages ozone layer / depletes ozone layer (1)UV (reaching Earths surface) increases / less UV absorbed / (more) UV reaches Earths surface (1) If Cl and / or ClO left in equation OR 2O33O2 Just (UV) harmful 6CH0201 1006<br />
(long wavelength) IR /infrared radiation (1) The molecule is polar OR (the molecule) changes its polarity OR polar bonds OR vibrational energy/vibrations of the bonds / stretching or bending increases OR (IR causes) bonds to vibrate (1) Marks are stand alone Acceptable Answers The C-F bond is (very) strong OR C-F bond is (much) harder to break than the C-Cl bond OR UV/radiation does not have enough energy /does not have (high) enough frequency Mark Reject Any mention of electronegativity OR mention of bond polarity scores (0) Acceptable Answers Reject Mark Question Number 22(d)(i) Question Number 22(d)(ii) QWC UV / ultraviolet Just molecule vibrates (0) 6CH0201 1006<br />](https://learnah.org/wp-content/uploads/2018/08/June_2010_MS_-_Unit_2_Edexcel_Chemistry_A-level_22-0.jpg)
