Upload
khangminh22
View
0
Download
0
Embed Size (px)
Citation preview
1091
0100
01ADDITIONAL MATERIALS
In addition to this examination paper, you will need a:• calculator;• copyofthePeriodic TablesuppliedbyWJEC.Referto itforanyrelative atomic masses you require.
INSTRUCTIONS TO CANDIDATES
Useblackinkorblackball-pointpen.Donotusegelpenorcorrectionfluid.Writeyourname,centrenumberandcandidatenumberinthespacesatthetopofthispage.Section A Answer allquestionsinthespacesprovided.Section B Answer allquestionsinthespacesprovided.Candidates are advised to allocate their time appropriately betweenSection A (10 marks) and Section B (70 marks).
INFORMATION FOR CANDIDATES
Thenumberofmarksisgiveninbracketsattheendofeachquestionorpart-question.Themaximummarkforthispaperis80.Youranswersmustberelevantandmustmakefulluseoftheinformationgiventobeawardedfullmarksforaquestion.The QWC labelalongsideparticularpart-questionsindicatesthosewheretheQualityofWrittenCommunicationisassessed.If you runout of space, use the continuationpage at the backof the booklet, taking care tonumberthequestion(s)correctly.
SJJ*(S12-1091-01)
Surname
Other Names
CandidateNumber
2
CentreNumber
GCE AS/A level
1091/01
CHEMISTRY CH1
P.M. TUESDAY, 15 May 2012
1½ hours
FOR EXAMINER’SUSE ONLY
Section Question Mark
A 1-5
B 6
7
8
9
10
TOTAL MARK
© WJEC CBAC Ltd.
PMT
2
(1091-01)
Examineronly
SECTION A
Answer all questions in the spaces provided.
1. Sketchadiagramtoshowtheshapeofap orbital. [1]
2. Completethefollowingdefinitionofrelative atomic mass: [1]
Therelativeatomicmassofanelementistheaveragemassofoneatomoftheelementrelativeto
3. Statewhichoneofthefollowingcontainsthegreatestnumberofmolecules. [1]
A 3gofhydrogen
B 32gofoxygen
C 36gofwater
D 66gofcarbondioxide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4. Phosgeneisacompoundofcarbon,oxygenandchlorine.Itisusedtomakepolyurethanesandpolycarbonates.Itspercentagecomposition,bymass,isasfollows.
C 12.1 % O 16.2 % Cl 71.7 %
(a) Calculatetheempiricalformulaofthiscompound. [2]
(b) Whatother informationwouldyouneedtoknowtobeable todeduce themolecular formulaofthiscompound? [1]
© WJEC CBAC Ltd.
PMT
(1091-01)
5. (a) Theelectronicstructuresoffiveatoms,A to E,arelistedbelow.Arrangetheseatomsinorderofincreasingmolarfirstionisationenergy. [2]
Turn over.
1091
0100
03
3 Examineronly
Atom A B C D E
Electronicstructure 1s2 1s2 2s2 1s2 2s2 2p1 1s2 2s2 2p3 1s2 2s2 2p6
lowest . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . highest
(b) State,givinga reason foryourchoice,whichoneof the followinggives the first fourionisationenergiesforsilicon,Si. [2]
Ionisationenergy/kJmol–1
1st 2nd 3rd 4th
W 496 4563 6913 9544
X 578 1817 2745 11578
Y 738 1451 7733 10541
Z 789 1577 3232 4356
Letter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Reason . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Section A Total [10]
© WJEC CBAC Ltd.
PMT
4
(1091-01)
Examineronly
SECTION B
Answer all questions in the spaces provided.
6. Magnesiumisbestknownforburningwithacharacteristicbrilliantwhitelight,howeverinindustryitisthethirdmostcommonlyusedstructuralmetal.ThemetalitselfwasfirstproducedbySirHumphryDavyin1808bytheelectrolysisofamixtureofmagnesiaandmercuryoxide.
(a) Magnesiumhasthreestableisotopes24Mg,25Mgand26Mg.
(i) Statethenumberofprotonspresentinanatomof24Mg. [1]
(ii) Deducethenumberofneutronspresentinanatomof26Mg. [1]
(iii) Inordertocalculatetherelativeatomicmassofmagnesium,whatwouldyouneedtoknowinadditiontotherelativemassofeachisotope? [1]
(b) Magnesiumalsohasaradioactiveisotope28Mgwhichhasahalf-lifeof21hours.
(i) Ifyoustartedwith2.0gof28Mg,calculatethemassofthisisotoperemainingafter84hours. [1]
(ii) Name one usefulradioactiveisotopeandbrieflydescribehowitisusedinmedicine,industry or analysis. [2]
© WJEC CBAC Ltd.
PMT
(1091-01)
(c) Inordertoobtainamassspectrumofagaseoussampleofmagnesium,thesamplemustbe ionised.
(i) Statehowthemagnesiumatomsareionisedinthesample. [1]
(ii) Giveareasonwhyitisnecessarytoionisethemagnesiumatomsinthesample. [1]
(iii) Statehowtheionsofmagnesiumareseparated. [1]
(d) Magnesium reacts with nitrogen forming magnesium nitride, which is an ioniccompound.
By inserting arrows to represent electrons, complete the boxes below to show theelectronicconfigurationofanitrideion,N3–. [1]
Turn over.
1091
0100
05
5 Examineronly
1s 2s 2p 3s 3p
(e) Magnesiumnitridereactswithwatertoformmagnesiumhydroxideandammonia.
Mg3N2 + H2OMg(OH)2 + NH3
(i) Balancetheequationabove. [1]
(ii) Calculate theminimummass ofmagnesiumnitride required to form 1.75 g ofmagnesiumhydroxide,givingyouranswertothreesignificantfigures. [3]
Total [14]© WJEC CBAC Ltd.
PMT
6
(1091-01)
Examineronly
7. Judithcarriedoutthreeexperimentstostudythereactionbetweenpowderedmagnesiumandhydrochloricacid.
Sheusedagassyringetomeasurethevolumeofhydrogenevolved,atroomtemperatureandpressure,atsetintervals.Ineachcase,theamountofacidusedwassufficienttoreactwithallthemagnesium.
Mg(s)+2HCl(aq)MgCl2(aq) + H2(g)
ThedetailsofeachexperimentareshowninTable1below.
Experiment Massofmagnesium/g
VolumeofHCl/cm3
ConcentrationofHCl/moldm–3
A 0.061 40.0 0.50
B 0.101 40.0 1.00
C 0.101 20.0 2.00
Table 1
The results obtained in experiment C are shown in Table 2 below.
Table 2
Time/s Volumeofhydrogen/cm3
0 0
20 50
40 75
60 88
80 92
100 100
120 100
© WJEC CBAC Ltd.
PMT
(1091-01) Turn over.
1091
0100
07
7 Examineronly
(b) (i) Stateinwhichexperimentthereactionbeginsmostrapidlyanduse the graph to explainyourchoice. [2]
(ii) ByreferringtoTable1giveanexplanationofyouranswerinpart(i). [1]
(c) Statethevolumeofhydrogenevolvedafter30secondsinexperimentB. [1]
(a) TheresultsforexperimentsA and Bhavealreadybeenplottedonthegridbelow.
Onthesamegrid,plottheresultsforexperimentCanddrawalineofbestfit. [3]
Time/s
00
10
20
30
40
50
60
70
80
90
100
20 40 60 80 100 120 140 160 180
Volu
meof
hyd
roge
n/c
m3
B
A
© WJEC CBAC Ltd.
PMT
8
(1091-01)
Examineronly
(d) UsingonlythevaluesinTable1,showthattheacidisinexcessinexperimentC. [2]
(e) (i) In experiment A, 0.061g of magnesium produces 60cm3 of hydrogen. If 0.122g of magnesium were used, under the same conditions, then 120 cm3 would be produced.Explainwhyusing0.610 gwouldnotproduce600 cm3ofhydrogen. [1]
(ii) Calculatethevolumeofhydrogenproducedusing0.610 gofmagnesium. [2]
(1moleofgasmoleculesoccupies24 dm3at25°C)
(f) StateonemethodofslowingdownthereactioninexperimentCandusecollisiontheorytoexplainyourchoice.Assumethatthequantitiesofmagnesiumandhydrochloricacidare the same as those in Table 1. [3]
QWC [1]
Total [16]
© WJEC CBAC Ltd.
PMT
(1091-01)
8. (a) Thevastmajorityofmotorvehiclesworldwidearepoweredbypetrolordieselwhichcomefromcrudeoil.Givetworeasonswhywecannotrelyindefinitelyonoilasasourceoftransportfuel. [2]
(b) Manyvehiclemanufacturersaroundtheworldhavemadethedevelopmentofalternativefuelsapriority.Onesuchfuelbeingstudiedishydrogen.
Itsmainadvantageisthattheonlywasteproductiswater,howeverhydrogendoesnotoccurnaturallyonEarth.Itisproducedbypassinganelectriccurrentthroughwater.
(i) Aleadingcarmanufacturersaid, “Carspoweredbyhydrogenwillbepollution-free”. Givetworeasonswhythisisnotnecessarilytrue. [2] QWC [1]
(ii) Aspokespersonforasafetygroupsaid, “Hydrogencanburnexplosively.Itmustnotbeusedincarsunlessitis100%safe”. State,givingareason,whetheryouagreewiththis. [1]
Turn over.
9 Examineronly
© WJEC CBAC Ltd.
PMT
10
(1091-01)
Examineronly
(c) Thefirstlineinthevisibleatomicemissionspectrumforhydrogenhasawavelengthof656nm,whilethatforheliumhasawavelengthof707nm.
State,givingareason,whichlinehas
(i) thehigherfrequency, [1]
(ii) thehigherenergy. [1]
(d) Thefirstionisationenergyofheliumis2370kJmol–1whilethatofneonis2080kJmol–1. Explainwhyneonhasalowerfirstionisationenergythanhelium. [2]
(e) Anothernoblegas is radon. Itsmore stable isotope 222Rnhasahalf-lifeof 3.8days,decaysbyα-emissionandisresponsibleforthemajorityofthepublicexposuretoionisingradiation.
(i) Givethesymbolandmassnumberoftheatomformedbythelossofoneα-particlefromanatomof222Rn. [1]
(ii) Explainwhydoctorsareconcernedthatanover-exposuretoradonmaycauselungcancer. [1]
Total [12]
© WJEC CBAC Ltd.
PMT
(1091-01) Turn over.
11 Examineronly
φ
9. Ethanolisanimportantindustrialchemicalandcanbemadebythedirecthydrationofetheneusingaphosphoricacidcatalyst.
CH2 CH2(g)+H2O(g)s CH3CH2OH(g)∆H=–46kJmol–1
(a) State,givingyourreasons,thegeneralconditionsoftemperatureandpressurerequiredtogiveahighequilibriumyieldofethanolinthisprocess. [4]
QWC [1]
(b) Usingthestandardenthalpychangeforthereactionaboveandthestandardenthalpychangesofformation(∆H
f )giveninthetablebelow,calculatethestandardenthalpychangeofformationofgaseousethanol. [3]
Compound ∆H f/kJmol–1
CH2 CH2(g) 52.3
H2O(g) –242
φ
© WJEC CBAC Ltd.
PMT
12
(1091-01)
Examineronly
(c) Anotherwayofcalculatingtheenthalpychangeofareactionisbyusingaveragebondenthalpies.Usethevalues inthetablebelowtocalculate theenthalpychangeforthedirecthydrationofethene. [3]
CO
HHH
C C O
H
H
H
H
H
C
H
H
H
H
+
Bond Averagebondenthalpy/kJmol–1
348
612
412
360
463
(d) (i) Giveareasonwhythecalculatedvaluein(c)isdifferenttotheactualvalue, –46kJmol–1. [1]
(ii) Explainwhetheryouranswertopart(i)supportstheuseofaveragebondenthalpiestocalculatetheenergychangeforareaction. [1]
C C
C C
C H
C O
O H
© WJEC CBAC Ltd.
PMT
(1091-01)
(e) Phosphoricacidisanexampleofaheterogeneouscatalyst. Explain the term heterogeneousinthiscontext. [1]
(f) (i) Sketchontheaxesbelowtheenergyprofileforanexothermicreaction. [1]
Turn over.
13 Examineronly
(ii) Onthesameaxes,sketchandlabeltheenergyprofileifthesamereactioniscarriedoutusingacatalyst. [1]
Total [16]
Energy
Extentofreaction
© WJEC CBAC Ltd.
PMT
14
(1091-01)
Examineronly
10. BerianwasaskedtofindtheidentityofaGroup1metalhydroxidebytitration.
Hewastoldtousethefollowingmethod.
• Fillaburettewithhydrochloricacidsolution.
• Accuratelyweighabout1.14gofthemetalhydroxide.
• Dissolveallthemetalhydroxideinwater,transferthesolutiontoavolumetricflaskthenaddmorewatertomakeexactly250cm3ofsolution.
• Accuratelytransfer25.0cm3ofthissolutionintoaconicalflask.
• Add2-3dropsofasuitableindicatortothissolution.
• Carryoutaroughtitrationofthissolutionwiththehydrochloricacid.
• Accuratelyrepeatthetitrationseveraltimesandcalculateameantitre.
Berian’s results are shown below:
Massofmetalhydroxide=1.14g
Concentrationofacidsolution=0.730gHClin100cm3ofwater
Meantitre=23.80cm3
(a) GiveareasonwhyBeriandoesnotsimplyadd1.14gofmetalhydroxideto250cm3ofwater. [1]
(b) Name a suitable piece of apparatus for transferring 25.0cm3 of themetal hydroxidesolutiontoaconicalflask. [1]
(c) Statewhyheaddsanindicatortothissolution. [1]
(d) SuggestwhyBerianwastoldtocarryoutaroughtitrationfirst. [1]
© WJEC CBAC Ltd.
PMT
(1091-01)
(e) Explainwhyhecarriedoutseveraltitrationsandcalculatedameanvalue. [1]
(f) The equation for the reaction between themetal hydroxide andhydrochloric acid isgivenbelow.MrepresentsthesymboloftheGroup1metal.
MOH + HCl MCl + H2O
(i) Calculatetheconcentration,inmoldm–3,oftheHClintheburette. [2]
(ii) CalculatethenumberofmolesofHClusedinthetitration. [1]
(iii) DeducethenumberofmolesofMOHin25.0cm3ofthesolution. [1]
(iv) CalculatethetotalnumberofmolesofMOHintheoriginalsolution. [1]
(v) CalculatetherelativemolecularmassofMOH. [1]
(vi) DeducetheGroup1metalinthehydroxide. [1]
Total [12]
Section B Total [70]
15 Examineronly
© WJEC CBAC Ltd.
PMT
Questionnumber Write the question numbers in the left-hand margin
Examineronly
(1091-01)
16
© WJEC CBAC Ltd.
PMT
SJJ*(S12-1091-01A)
GCE AS/A level
1091/01-A
CHEMISTRY – PERIODIC TABLEFOR USE WITH CH1
P.M. TUESDAY, 15 May 2012
PMT
(1091-01A)
2
TH
E P
ER
IOD
IC T
AB
LE
12
Gro
up3
45
67
0
1 2 3 4 5 6 7
6.94 Li
Lith
ium
3
9.01 Be
Bery
llium
4
10.8 B
Bor
on 5
12.0 C
Car
bon
6
14.0 N
Nitr
ogen
7
16.0 O
Oxy
gen
8
19.0 F
Fluo
rine
9
20.2
Ne
Neo
n10
23.0
Na
Sodi
um11
24.3
Mg
Magn
esium
12
27.0 Al
Alum
inium
13
28.1 Si
Silic
on14
31.0 P
Phosp
horus
15
32.1 S
Sulfu
r16
35.5 Cl
Chlo
rine
17
40.0
Ar
Arg
on18
39.1 K
Pota
ssium
19
40.1
Ca
Cal
cium
20
45.0 Sc
Scan
dium
21
47.9 Ti
Tita
nium
22
50.9 V
Vana
dium
23
52.0 Cr
Chro
mium
24
54.9
Mn
Man
gane
se25
55.8 Fe Iron 26
58.9
Co
Cob
alt
27
58.7 Ni
Nic
kel
28
63.5
Cu
Cop
per
29
65.4
Zn
Zin
c30
69.7
Ga
Gal
lium
31
72.6
Ge
Germ
anium
32
74.9 As
Ars
enic
33
79.0 Se
Selen
ium
34
79.9 Br
Brom
ine
35
83.8
Kr
Kry
pton
36
85.5
Rb
Rubid
ium37
87.6 Sr
Stro
ntium
38
88.9 Y
Ytt
rium
39
91.2 Zr
Zirco
nium
40
92.9
Nb
Nio
bium
41
95.9
Mo
Molyb
denum
42
98.9 Tc
Tech
netiu
m43
101
Ru
Ruthe
nium
44
103
Rh
Rhod
ium
45
106
PdPa
lladiu
m46
108
Ag
Silv
er47
112
Cd
Cadm
ium48
115 In
Indi
um49
119
Sn Tin 50
122
SbAn
timon
y51
128
TeTe
lluriu
m52
127 I
Iodi
ne53
131
Xe
Xen
on54
133
Cs
Caes
ium
55
137
Ba
Bar
ium
56
139
La
Lanth
anum
57
179
Hf
Haf
nium
72
181
TaTa
ntalu
m73
184 W
Tung
sten
74
186
Re
Rhen
ium
75
190
Os
Osm
ium
76
192 Ir
Irid
ium
77
195 Pt
Plat
inum
78
197
Au
Gol
d79
201
Hg
Mer
cury
80
204
Tl
Thal
lium
81
207
Pb Lea
d82
209 Bi
Bism
uth
83
(210
)Po
Polo
nium
84
(210
)A
tA
stat
ine
85
(222
)R
nR
adon
86
(223
)Fr
Fran
cium
87
(226
)R
aR
adiu
m88
(227
)A
cAc
tiniu
m89
‣ ‣‣
1.01 H
Hydr
ogen
1
4.00 He
Heliu
m2
d Bl
ock
s Blo
ckPe
riod
p Bl
ock
140
Ce
Cer
ium
58
141 Pr
Pras
eody
mium
59
144
Nd
Neo
dym
ium
60
(147
)Pm
Prom
ethi
um61
150
SmSa
mar
ium
62
(153
)Eu
Euro
pium
63
157
Gd
Gad
oliniu
m64
159
Tb
Terb
ium
65
163
Dy
Dys
pros
ium66
165
Ho
Hol
miu
m67
167
ErEr
bium
68
169
TmTh
uliu
m69
173
Yb
Ytter
bium
70
175
LuLu
tetiu
m71
232
Th
Thor
ium
90
(231
)Pa
Prot
actin
ium91
238 U
Ura
nium
92
(237
)N
pN
eptu
nium
93
(242
)Pu
Plut
oniu
m94
(243
)A
mA
mer
icium
95
(247
)C
mC
uriu
m96
(245
)Bk
Berk
elium
97
(251
)C
fCa
liforn
ium98
(254
)E
sEi
nstei
nium
99
(253
)Fm
Ferm
ium
100
(256
)M
dM
ende
leviu
m10
1
(254
)N
oN
obeli
um10
2
(257
)Lr
Lawr
enciu
m10
3
f Blo
ck
‣ Lan
than
oid
e
lem
ents
‣‣ A
ctin
oid
e
lem
ents
Ar
Sym
bol
Name Z
rela
tive
atom
icm
ass
atom
icnu
mbe
r
Key
PMT