1

A/L Chemistry 2014 Model Paper (Sipsara Udana, Uva Province)

Dr Vajira Seneviratne, University of Peradeniya jHQy.; rpkd

A - fldgi

m%Yak y;rgu ms<s;=re imhkak'

01. (a) hk uQ, øjHh wdYs%;j ms<s;=re imhkak'

1) yd hk TlaislrK wxl olajk uQ, øjHh jkafka"

2) j¾Kj;a Tlaihsv idokqfha"

3) m%n,;u Tlaisydrlh jkafka"

4) m%n,;u Tlaisldrlh jkafka"

5) nyqrEmsl;dj fmkajk uQ, øjH jkafka"

6) Tlaihsvh iy yhsv%hsvh hk folg wdï,sl jkafka"

7) by<u w.hla we;s c, ødjKhla ,nd fokafka"

(b) my; wlajd we;af;a øjHh lSmhl øjdxl úp,kh fõ'

øjHh ialkaOh øjdxlh$˚C

Ne 20 -248

Ar 40 -189

H2O 18 0

NaF 42 993

C 12 3550

i. by< úp,;djhka meyeÈ,s lrkak'

ii. NaF j,g idfmalaIj MgF2 j, øjdxlh jeä fõoehs , wvq fõ±hs meyeÈ,s

lrkak'

(c) A yd B hkq mrudKql l%udxlh 20g wvq uQ,øjH folls' 30˚C § A c,h iuÕ C

kï jdhqj msglrñka D ødjKh idohs' B c,h iuÕ m%;sls%hd fkdlrk kuq;a D

ødjKh iuÕ m%;sls%hd lr C jdhqj msg lrñka E ødjKh ,nd foa'

i. ridhksl ixfla; Ndú;d lr A, B, C kï lrkak' Uva P

rovinc

e Sips

ara U

dana

& st

uden

tlank

a.com

2

ii. E ødjKhg HCl iaj,amh neÕska tla lrk úg ±lsh yels ksÍlaIKh

fudkjdo@

02. (a) ixY=oaO c,h T kue;s ksh; WIaK;ajfhaoS tys jdYamh iu`. .;sl

iu;=,s;;djfha we;' túg jdYam l,dmfha mSvkh P˚ úh' tu WIaK;ajfha§u

c,hg D2O tla lrk ,È' túg moaO;sfha jdYam mSvkh P úh' c,fha ;dmdxlh

100˚C jk w;r D2O j, ;dmdxlh 102˚C fõ' ñY%Kfha 75% c,h wvx.= jk

w;r b;sßh D2O fõ'

i. ñY%Kfha D2O j, ujq, Nd.h i|yd m%ldYkhla jHq;amkak lrkak'

ii. ñY%Kfha uq¨ jdYam mSvkh hk iïu; wdldrhg úp,kh jk

nj fmkajkak'

iii. ñY%Kfha jdYam mSvk ixhq;s m%ia:drh w¢kak'

iv. D2O m%;sY;h 80% la jk ødjKhla Nd.sl wdijkhg Ndckh l< úg

ixrpl fjka jk whqre ;dmdxl ixhq;s m%ia:drfha olajkak'

c,h iuÕ t;fkda,a yd HCl ñY% l< úg c,fha jdYam mSvk by; moaO;sfha

mSvk j,g idfmalaIj olajkak'

v. by; (v) ys m%ldY j,g fya;= moaO;sj, wka;¾ wKql wdl¾IK n, weiqfrka

olajkak'

(b)

i. 1000K WIaK;ajfha§ CO2 j, j¾. uOHhk uQ, m%fõ.h .Kkh lrkak'

ii. CO2 j, Wmßu iïNdjHh m%fõ.h f,i woyia lrkafka l=ulao@

iii. CO2 j, m%fõ. jHdma;sh ksrEmKh lrk fnda,aúiaudka jHdma;sh my;

m%ia:drfha ksrEmKh lrkak'

wKq Nd.h

m%fõ.h

iv. CO2 j, Wmßu iïNjHh m%fõ.h iy j¾. uOHhk uQ, m%fõ.h by;

m%ia:drfha o< jYfhka olajkak'

3

v. WIaK;ajh 2000 K olajd by< kexjQ úg CO2 j, m%fõ. jHma;sh fjkia jk

whqre m%ia:drfha olajkak'

vi. m%ia:drfha ,nd .; yels ks.uk 2 olajkak'

03. (a) my; m%;sls%hd j,ska ,efnk M, j, jHQy ,shkak'

i.

ii. 1 ) CH3MgCl

2 ) jeämqr H2SO4

iii. NaNO2 / HCl(5 - 10o C) D NaOH E

(b) my; ksÍlaIK i`oyd fya;= bÈßm;a lrkak'

i. kue;s ixfhda.h úc,SlrKhg Ndckh l< úg m%Odk

M,h f,i ,efí'

ii. A) B) C)

A, B yd C c,Sh NaOH iuÕ m%;sls%hd lrkq ,nkafka fjkia wdldr j,sks'

Uva

Prov

ince S

ipsara

Uda

na &

stud

entla

nka.c

om

4

(c) my; ldnksl mßj¾;k wju mshjr .Kkdjlska isÿ lrkafka flfiao@

i.

m%;sldrl NaBH4, conc, H2SO4, ldnksl fmfrdlaihsâ" HBr, NaOH, PCl3, Mg,

úh<s B;r" KMnO4

ii. +

m%;sldrl Zn(Hg), HCl, PCl5, LiAlH4, Mg úh<s B;r H2SO4, Br2, CCl4, C2H5OH,

KOH ks¾c,Sh AlCl3

04. (a) c,Sh ødjKhl Fe3+, Al3+ yd Co2+ whk we;' fuu c,h ødjKhg NH4Cl oud bka

miq NH4OH tl;= lr r;a lrk ,È' miqj ødjKh fmrd .kakd ,È' bka miq

fmrKhg H2S nqnq,kh lrk ,È'

i. m<uq wjlafYamfha j¾Kh l=ulao@

ii. wjlafIamfha wvx.= øjH j, iQ;% ,shkak'

iii. fmrKfha j¾Kh ,shkak'

iv. fmrKfha wvx.= ixfhda.fha iQ;% ,shkak' m<uq wjlafYamh c,Sh NaOH j,ska

fidaok ,È' fidaÞ ,efnk ødjKhg HCl ìxÿ jYfhka tl;= lrk ,È'

v. by; kj fmrKhg HCl tla l< úg ,efnk ksÍlaIK fudkjdo@

vi. by; ksÍlaIK j,g wÞ< m%;sls%hd ,shkak'

vii. by; m<uqj ,efnk fmrKhg H2S nqnq,kh lsÍfï§ ,efnk ksÍlaIK

,shkak'

5

(b) my; m%;sls%hd fYa%‚h i,lkak'

(NH4)2 Cr2O7 SO2 / H2SO4 c,Sh ødjKh

NH4OH

>kh

jeämqr c,Sh NaOH oeóu'

H2O2

i. A isg E olajd øjH j, iQ;% ,shkak'

ii. my; wjia:d i|yd iólrK bÈßm;a lrkak'

a. (NH4)2CrO7 D

b.

A

B C

D

E

Uva P

rovinc

e Sips

ara U

dana

& st

uden

tlank

a.com

6

rpkd

B – fldgi (05,06, 07)

m%Yak follg muKla ms<s;=re imhkak'

05. (a)

i. hkq c,fha u| jYfhka ødjH >k whksl ixfhda.hls' fuys i|yd

m%ldYkhla wÞ< uq,O¾u weiqßka jHq;amkak lrkak'

ii. c,Sh ødjKhla ;=, Ag+(aq), Hg+2(aq) iy whk wvx.=h' fïjdfha tlsfklg

idfmalaIj idkaøK 0.1 moldm-3 fõ' fuu ødjKhg NaI ødjKhla l%ufhka

tl;= lrk ,o kï whvhsvhla f,i uq,skau wjlafIam jkqfha l=uk

legdhkhg o fmkajd fokak'

wÞ< WIaK;ajfh§ AgI(s) j,

HgI2(s) j,

iii. fojk legdhkh wjlafIam ùu wdrïN jk fudfydf;a§ wjlafIam jQ

lgdhkfha" wjlafIam fkdù ødjKfha b;sÍ ù we;s legdhk idkaøK m%;sY;h

fldmuK o@

(b) jdhqf.da,Sh jd;fha mßudj wkqj 0.035% la CO2. mj;S' lsishï WIaK;ajhl§

CO2(g) CO2(aq) hk iu;=,s;;dj i|yd fykaß ksh;h KH =

3.3 × 10-4 mol dm-3 K Pa-1 fõ'

1) mSvkfha§" CO2 j, c,fha ødjH;dj .Kkh lrkak'

2) c,fha Èhù we;s CO2 c,h iuÕ m%;sls%hd ù ldnfkag yd nhsldnfkag whk idohs'

i. HCO3-(aq) CO32-(aq) + H+(aq) hk iu;=,s;;djg i|yd

m%ldYkhla ,shkak'

ii. ldur WIaK;ajfha§ fuu iu;=,s;h i|yd iu;=,s;;d ksh;fha w.h

c,h idïm,hl wvx.= HCO3- whk idkaøKh CO32-

whk idkaøKh fuka oi .=Khla fõ' fuys fidhkak'

iii. HCO3- yd CO32- whk wvx.= fjk;a idïm,hl ls' fuu w.h;a

by; fldgfia§ Tfí ms<s;=r;a Ndú;d lr fuu c, idïm,fha we;s

HCO3- yd CO32- idkaøK w;r wkqmd;h fidhkak'

7

06. (a)

1) W;afma%rl ls%hdldrk m%Odk l%u 2la ,shkak'

2) 2 H2O2 2H2O + O2, KI uÕska fukau legf,aä uÕska W;afma%rKh

lrhs'

A - úfhdackh fyd legf,aä ke;s úg isÿjk wdldrh

B - yuqfõ isÿjk wdldrh

C - legf,aä we;s úg isÿjk wldrh my; m%ia:drfha ,l=Kq lrkak'

Yla;sh

m%;sl%shd ldKavdxlh

3) m%;sls%hdj uÕska W;afm%arKh fõ' j, m%;sls%hdj meyeÈ,s lsÍug hdka;%Khla

,shkak'

(b) my; olajd we;af;a wdï,sl udOHfha yd whvhsÜ whk w;r m%;sls%hdfõ iS>%;djh

iïnkaO o;a; iuQyhla fõ'

0'02 moldm-3 H202 0'2 moldm-3 KI 0'2 moldm-3 iS.%;dj

1 0'01 0'01 0'1 1'75 x 10-6 2 0'03 0'01 0'1 5'25 x 10-6 3 0'03 0'02 0'1 1'05 x 10-5 4 0'03 0'02 0'1 1'05 x 10-5

1' m%;sls%hdfõ fõ. m%ldYkh jHq;amkak lrkak'

2' 1 yd 2 mÍlaIK j,g wÞ<j my; m%ia:dr iïmQ¾K lrkak'

0.03

0.02

0.01

[H2O2]

ld,h (t)

S

iS>%;dj

moldm-3S-1

[H2O2]

[H2O2] Uva P

rovinc

e Sips

ara U

dana

& st

uden

tlank

a.com

8

(c) my; tka;e,ams o;a; i,lkak'

wï,h idkaøKh iïu; WÞiSlrk tk;e,amsh a

KJ mol-1

HCl 0'1 -57'3

CH3COOH 0'1 55

H+(aa) 0'1 -57'3

1' by; o;a; fláfhka meyeÈ,s lrkak'

2' CH3COOH(aq) j, iïu; whkSlrk tka;e,amsh fidhkak'

07.

(a) 0.1 moldm-3 HCl yd 0.1 moldm-3 CH3COOH j, 25cm-3-ne.ska f.k 0.1 moldm-3

NaOH iuÕ fjk fjku wkqudmkh lrk ,È' [ Ka (CH3COOH) = 1.6 × 10-5 moldm-3]

1' HCl yd NaOH w;r wkqudmkhg wÞ< iul;d ,laIfha .Kkh lrkak'

2' CH3COOH yd NaOH w;r wkqudmkhg wÞ< ,laIfha w.h fidhkak'

3' by; wkqudmk folg wÞ< úp,kh my; m%ia:drfha i,l=Kq lrkak'

NaOH

pH

1

2

5

1

9

4

3

10

8

6

7

11

12

13

9

4. by; wkqudmk folg wÞ< o¾Yk my; j.=fjka f;dard ,shkak'

o¾Ylh mrdih

fu;s,a jh,Ü 0-1

fu;s,a Tf¾kaÊ 3-4

fn%dau;hsfuda,a íÆ 6-7

*sfkdma;,Ska 9-10

(b) my; wdldrhg f,day folla tlsfkl iam¾Yj we;'

Eǿ Cu+2/Cu = +0.34 v

Eǿ Fe+3/Fe = -0.4 v

1' moaO;sfha isÿúh yels m%;sls%hd i|yd ;=,s; iólrKh ,shkak'

2' moaO;sfha i;H jYfhkau isÿjk m%;sls%hdj fya;= olajñka meyeÈ,s lrkak'

3' Eǿ Zn+2

/Zn = -0.76 v kï by; moaO;sh iuÕ Zn f,dayh iïnkaO l< úg

isÿjk m%;sls%hd ,shkak'

4' wjqreÿ 3lg muK miq by; moaO;sfhka f.k ishqï l=vq njg wUrd ;kql

H2SO4 ødjKhla iuÕ kgjd fmrd .kakd ,È' túg ,efnk fYaIfha ialkaOh

0.635g úh' ,efnk fmrkh 250cm3 olajd ;kql lrk ,È' ;kql ødjKh

25cm3oaú;sl m%udŒ KMNO4 ødjKhla iuÕ wkqudmkh l< úg jeh jQ mßudj

20cm3úh' ødjKfha ;j;a f.k l=vq iuÕ fid,jd by; KMNO4 ødjKh iuÕu

wkqudmkh l< úg jehfjk mßudj 60cm3 úh' by; KMNO4ødjKfha

c,h

F e

C u

2H2O + 02 + 4e 4OH-

Eǿ = +0.4V

Uva P

rovinc

e Sips

ara U

dana

& st

uden

tlank

a.com

10

25cm3iu`. wdï,sl udOHfha m%;sls%hd lsÍug jeh jQ 0.02moldm-3 mßudj

40cm3úh'

i. isÿjk ish¨ m%;sls%hd ;=,s; ridhksl iólrK j,ska bÈßm;a lrkak'

ii. by; moaO;sfha mej;s Fe, Fe2O3 yd Cu m%;sY; fidhkak'

iii. ñY% f,dayh ;kql H2SO4 j, Èh lsÍug wÞ, fya;= bÈßm;a lrkak'

C – fldgi (08,09, 10)

m%Yak follg muKla ms<s;=re imhkak'

08. i. A hkq wldnksl ixfhda.hls'

mÍlaIKh ksÍlaIKh

A ys c,Sh ødjK fldgilg ;kql

wï,h tla lrk ,È' ,d ly wú,;djla ±lsh yel'

A ys c,Sh ødjK fldgilg ys

ødjKh lrk ,o ødjK iaj,amhla

tla lrk ,È'

$ ødjKfha j¾Kh wj¾K úh'

A ys c,Sh ødjK fldgilg

ødjK iaj,amhla tla lrk ,È'

m<uqj iqÿ wjlafIamhla ,nd ÿka w;r

iaj,am fõ,djlska l¨ meye úh'

A >kh iaj,amhlg myka is`t mÍlaIdj

isÿ lrk ,È' oï j¾Kh iys; ±,a,la ,nd ÿks'

fya;= olajñka ixfhda.fhys wvx.= wekdhkh yd legdhkh y÷kd.kak'

ii.my; rEmfha olajd we;s isg olajd ixfhda. j, ridhksl iQ;% ,shkak' fuu

wjlafIamh WKq c,fha ÈhjQ w;r isis,a jQ úg kej; we;s fõ'

11

; HCl l¨

+ +

K3 [ FeCCN)6]

K2CrO(aq) BaCl2(aq)

;Èka

r;a

lsÍu

ÿUqre ly iqÿ

09. (a) ødjKhl wvx.= Fe+2, Fe+3 úYaf,aIKh i|yd my; olajd we;s mshjr wkq.ukh

lrhs'

mshjr 1

Fe+2 yd Fe+3 whk wvx.= x kï ødjKhlska 25.00cm3 la f.k thg

idkaøKh KMnO4 ødjKhlska 75cm3 la tla lrk ,È' tys§ ,enqk

oï meye ødjKfhka 25.00 cm3 la f.k idkaøKh jQ ìhqfrÜgqfõ

we;s Tlai,sia wï,h 75 cm3iuÕ wkqudmkh isÿ lrk ,È' tys§ ,enqk ìhqfrÜgqfõ

mdGdxlh la úh'

mshjr 2

Fe+2 yd Fe+3 whk wvx.= x kï ødjKhka 100 cm3 f.k thg jeämqr SO2 jdhqj

nqnq,kh lrk ,È' tu ødjKfhka 25.00cm3 f.k thg kej; jQ

S (s)

M(aq)

Q(g)

M(s)

T(s)

N(aq) O(s)

R(S)

U(S)

V(aq)

P(aq)

Y(aq)

ÿUqre j,h

FeSO4 / yd H2SO4 ìxÿ lSmhla

ks,a

X(S) W (aa)

Conc. HNO3 ìxÿ lSmhla

ÿUqre

NH4OH(4) ,d ly ÿTqre

Uva P

rovinc

e Sips

ara U

dana

& st

uden

tlank

a.com

12

KMnO4 ødjK 75cm3la tla lrk ,È' túg ,enqK oï meye ødjKfhka 25.00cm3

la iuÕ H2C2O4 wkqudmkh l< úg ìhqfrÜgq mdGdxlh 6.50 cm3 úh'

i. isÿjk ish`tu m%;sls%hd i|yd ;=,s; ridhksl iólrK ,shkak'

ii. ødjKfha wvx.= yd whk idkaøK fjk fjku fidhkak'

10& (a)

1' WKq idkaø NaOH ;=<g whäka l=vq jYfhka tla l< úg olakg ,efnk

ksÍlaIK 3la ,shkak'

2' by; ^1& ys isÿjk m%;sls%hdj ,shkak'

3' by; ^2& ys M,h jYfhka ,efnk ødjKh ìxÿ jYfhka CuSO4 ødjKhg tla

lrk ,È' túg olakg ,efnk ksÍlaIK ,shkak'

4' by; ^3& ys isÿjk m%;sls%hd ,shkak'

5' by; ^3& ødjKh fmrd fmrKhg H2SO4 j,ska wdï,SlrKh lr thg ìxÿ

jYfhka Na2S2O3 tla lrk ,È'

i. olakg ,efnk ksÍlaIK ,shkak'

ii. isÿjk m%;sls%hd ,shkak'

(b) A kue;s ixfhda.hl ixhq;sh my; olajd we;'

Na = 16.67% S = 23.19% O = 57.97%

Na = 23 S = 32 O= 16 H= 1

1' A ys wKqNúl iQ;%h f.dv kÕkak'

2' A ys c,Sh K2CO3 ødjKhla yd tlaj fõ.fhka jdhqj msg lrhs kï y÷kd

.kak'

3' A ye¢kSug wÞ< m%;sls%hd i|yd iólrK ,shkak'

4' A idok wekdhkfha yevh

13

5' A ys mQ¾K ,jKh BaCl2 iuÕ isÿ lrk m%;sls%hdfõ iólrK ,shkak'

(b) A kue;s uQ, øjH B kue;s uQ, øjHh yuqfõ ;Èka r;a l< úg ,efnk C kue;s

ixfhda.h c,fha Èh l< úg j¾Kj;a ødjKhla ,enqKs' th D úh' D j,g KI tla

l< úg ødjKh ÿUqre meyehg m;a jQ w;r E kue;s M,h ,enq‚' E ødjKhg kej;

B tla l< úg kej; D ,enq‚' E j,g c,Sh NH3 jeämqr tla l< úg fld< mdg

wjlafIamhla ,enq‚' D kue;s j¾Khla ødjKhg AgNO3 tla l< úg iqÿ

wjlafIamhla ,enqKq w;r th NH3 j, Èh úh' th F úh'

1' A isg F olajd øjH j, iQ;% ,shkak'

2' isÿjk m%;sls%hd wkqms<sfj,ska ,shkak'

3' D j,g KCN jeämqr tla l< úg ,efnk ksÍlaIK ,shkak'

4' by; ^3& ys ksÍlaIKh wÞ< m%;sls%hdj ,shkak'

5' by; ^3& ys ixfhda.hg D tla l< úg olakg ,efnk ksÍlaIK ,shkak'

6' by; ^5& ys ksÍlaIKhg wÞ< m%;sls%hdj ,shkak'

Uva P

rovinc

e Sips

ara U

dana

& st

uden

tlank

a.com