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Chemistry Paper 2C 2011
1) When Potassium reacts with water, fzzing occurs,
potassiummoves around, potassium melts, a lilac ame is seen
2) !ron is a solid that conducts electricity "aematite is a
metal
ore #mmonia is a su$stance %ormed in the "a$er process&odium
hydro'ide is a su$stance used to ma(e soap#mmonia is a su$stance
use to ma(e %ertilisers
) *a) *i) +agnesium is a metal that can used to ma(e a
spacepro$e to land on enus $ecause o% its very low density *1-)*ii)
.his metal would $e unsuita$le %or ma(ing a pro$e to landon enus
$ecause it would react with the sul%uric acid and theatmosphere*$)
&mall amounts o% lead can used in electrical circuits,
leadwould not $e suita$le %or use in the electrical circuits o%
apro$e to land on enus $ecause its low melting point,
thetemperature on enus is higher than the melting point o% lead*c)
.itanium would $e the most suita$le %or ma(ing a pro$e toland on
enus $ecause o% its low density .itanium has a highmelting point
*the temperature on enus is lower than themelting point o%
titanium), and it does not react with sul%uricacid and the
atmosphere
/) *a) (i)
● ethene has the displayed %ormula
● ethene is a gas at room temperature
● ethene $urns with a smo(y ame
● ethene is unsaturated
● ethene is insolu$le in water
● ethene can $e prepared %rom ethanol
● ethene is used to ma(e the polymer poly*ethene)
thene is descri$ed as unsaturated $ecause it contains a*car$on
to car$on) dou$le $ond
*ii) romine water is a dilute solution o% $romine that is
normallyorange$rown in colour $ut turns colourless when sha(en with
anal(ene &o it i% goes %rom orange to $row it means an al(ene
ispresent
*$) *i) 3uation that represents the preparation o% ethene
%rom
ethanol4
C2O5OH5 C2"/6 "27
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*ii) .he name given %or this type o% reaction is
8ehydration
9) When soap is sha(en with water, a lather %orms # lather is
acollection o% small $u$$les that %orm on the sur%ace o% the
water
ery little soap is needed to %orm a lather with pure waterWater
that needs a much larger 3uantity o% soap to %orm a lather iscalled
hard water Water $ecomes hard when certain compounds aredissolved
in it# student carried out an e'periment to fnd out which
compoundsma(e water hard.
*a).wo compounds that mad the water hard are +agnesiumchloride
and !ron *!!) Chloride
*$).he student carried out he e'periment three times with
eachcompound to chec( the relia$ility o% the results
*c) *ii) When the student %ound the anomalous result
he:sheshould have repeated the e'periment
*d).he name o% the apparatus that the student should use to
addthe soap solution is the $urette
*e).he average *mean) volume o% soap solution needed to %ormthe
lather with the magnesium chloride solution is41.60+1.70+1.65
3 ; 1raphite is $onded $ycovalent $ond, thus, it is held $y
wea( intermolecular %orces &inceit has wea( intermolecular
%orces, graphite would $e slippery andso%t enough to act as a
lu$ricant
*c) oth graphite and metal are $onded $y covalent $onding
this%eature allows graphite to conduct electricity, this helps
graphiteconduct electricity $ecause o% its delocalized
electrons
*d) 8iamond has got a giant covalent structure which car$on
atomshold each other $y strong covalent $ond "owever,
in$uc(minster%ullerene, atoms pac(ed closely together $ut $ound
$ywea( an der Waal=s %orce .hus, $uc(minster%ullerene re3uires
lessheat to overcome the attractive %orce than that o% diamond
-) *a) *i).he e3uation o% the decomposition o% sodium azide
*?a?)is4 2?a? *s) 5 2?a*l) 6 ?2*g)
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&odium azide is used to produce nitrogen gas to inate car
air$agsIf a car is involved in a collision, the sodium azide
decomposes.
The nitroen as is produced ver! rapidl! and the air"a inflates
almost immediatel!.
#mount of nitroen in moles in a full! inflated air"a (assumin
that the volume of
one mole of nitroen inside the air"a is 2$ dm%.
#mount of nitroen&108
24 & $.5 mol
(i) #mount of sodium azide re'uired to produce * dm% of
nitroen+
-I #/0 1I3 CH#T4 O/ O6
