Inter Molecular Spacing

Topics: Atom, Chlorine, Atomic number Pages: 23 (3218 words) Published: January 21, 2013
Mark Scheme (Results) Summer 2012

International GCSE
Chemistry (4CH0) Paper 1C Science Double Award (4SC0) Paper 1C

Edexcel Level 1/Level 2 Certificate
Chemistry (KCH0) Paper 1C Science (Double Award) (KSC0) Paper 1C

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Summer 2012 Publications Code UG031876 All the material in this publication is copyright © Pearson Education Ltd 2012


Expected Answer measuring cylinder B



Marks 6

C Ignore D Or 2D diagram (top pan) balance /scale(s) / weighing machine A or E

Ignore extra apparatus on top of tripod eg beaker Minimum is 2 vertical or diagonal lines with something on top

1 mark for each correct answer

Question number 1 (b)

Expected Answer M1 wear (safety) glasses / spectacles / goggles / eye protection It M2 salt /solution / water may spit out (when evaporating the salty water) / may get in your eye IGNORE references to hazards eg toxic / irritant OR M1 use (beaker) tongs / hot hand / (rigger/oven) glove(s) (to remove / lift the basin) M2 basin will / may be hot OR M1 tie hair back / tuck in tie M2 might catch fire (in Bunsen burner) the reason must match the precaution IGNORE references to wearing lab. coats / protective clothing



Marks 1 1

leave basin (to cool) before removing to avoid burning hand

crucible tongs / plastic gloves

1 (c) (2.9 x 2) = 5.8 (g)

Question number 2 (a) (i) (ii)

Expected Answer M1 calcium M2 magnesium Ca Mg


Reject any other answers

Marks 1 1

iron / zinc (iii) calcium magnesium zinc iron copper M1 for calcium as most reactive M2 for copper as least reactive M3 for remainder in correct order hydrogen / H2 all the (sulfuric) acid has reacted /all hydrogen (ions) have been replaced (by magnesium (ions)) OR acid has been used up/been neutralised / acid has run out IGNORE the acid is saturated / excess magnesium has been added (iii) magnesium sulfate (solution) IGNORE incorrect formula

Fe / Zn Ca Mg Zn Fe Cu

any other answers

1 3


(i) (ii)

H sulphuric for sulfuric hydrogen ions / H+ for acid all the magnesium / reactants used up

1 1

sulphate for sulfate MgSO4 description of filtration sieve crystallisation

1 1

(iv) filtration / filter (it / magnesium / solution) / decantation / decant (off the water / solution) IGNORE references to distillation / centrifuging / washing / evaporation after filtration

2 (c)

(i) (ii)

exothermic magnesium oxide IGNORE incorrect formula MgO

1 1

Question number 3 (a)

Expected Answer M1 precipitate of barium sulfate

Accept sulphate for sulfate insoluble barium sulphate / BaSO4 no (visible) change solution (formed) sulphate for sulfate insoluble calcium...
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