Csec Chemistry Paper 2 January 2019 304l4w

rESr coDE

FORM TP 2019005

0t212020

-l

JANUARY ]019

CARIBBEAIi. E\AMTNATIONS COUNCIL CARIBBEAN SECO\DARY EDUCATION CERTIF'ICATE@ ELA.MINATION CHEMISTRY Paper 02

- General

Proficiency

2 hours and 30 minutes

@

6

READ THE FOLLOWING INSTRUCTIONS CAREFTILL}" 1

This paper consists of SIX questions in TWO sections"

2.

Arsr.r,er

3.

Write your answ-ers in rhe spaces provided in this booklet.

4.

Do NOT rvdte in rhe margins.

5"

Where appropriate.

6"

You may use a silent. non-programmable calculator to ansrr er Juesrr,rns.

7

o o

.

"

ALL questions.

-{LL WORKING MUST BE SHOUN in this 5r.r,_r},1g1.

Ifyou

need to reurii: an\ answer and there is not enough space :l,iir so o1 the original page, you l-itlist use the extra lined page(s) provided at :h,- back of this booklet. to draw a line through your original ans* er.

8. If you use the extra page(s) you MUST

write the question number clear.ly in the box provided at the top of the extra page(s) ando where reler ant. include the question part beside the answer-.

DO NOT TL

R\

THIS P..\GE UNTIL YOTI ..l.RE TOLD TO DO SO.

Copyri$ C 2018

-

Caribbean Examinations Council All rights reserved.

A1?1)fi'{\/IANIIIAI?\."N1O TIEIilETilUHTSUHI

I .a

U

-)SECTIOI A \nsrr er -\lL questions in this section. Do NOT spend nlore than

1.

*10

minutes on Question 1'

salnple' An experiment was carrie.l ,-,iit tc detenl',ir: the percentage of iron in an iron salt sulfuric acid" dilute of mL a O.SdO g sample of iron sa,r * as placed ,n a conical flask. To it. 25"0 contents of the flask were 10 mL oiphosphoric acid anC 8 drops oian indicator were added. The until the end point rnixed ani titrated against a r-r.ul0 mo1 ,jm.' ...1Lrtion of potassium dictu"omate given 'Ihe beloll' ionic equatiritl tbr the reaction is u,as reached.

CrrO.,2'*

6Fe2*

+ i4H-

-

6Fer-

* 2Crr- -;H-O

titration. Figure 1 shows the burette readings of the initial and final voluntes of EACH @

@

@

:Ffi Initial

Final a

Titration

Initial Titration

1

FinaI 2

Initial Titration

Final 3

fRough)

Figure 1. Burette readings (a) a c)

,

List the apparatus that would be necessar-v to carry out the experiment.

O

o

(2 marks)

1

01212020/JANUARY 2019

It:It il lt il.1 ll l l:ll,llllllllllll

-5(b)

Use the information in

Fr:*:e I to complete'lable

1.

TABLE 1: TITRATIO\ \.{LUES OBTAINED F'ROM EXPBRT]VIENT Burctte Readings (cm''

r

Titration

Titration

1

2

Titration

3

Final volume

Initial volume Volume of solution used (9 marks) (c)

(i)

Use an asterisk t * ) to indicate the titration data tirat should be r-rsed to obtain the average titration \ L-,lume of,potassium dichromate used in the experiment.

(1 mark)

(ii)

Hence, calculate the avemge volume ofpotassium dichromate used in the experiment and record the r alue to two decimal places.

(2 marks) (d)

Using the information from (c) (ii). calculate the average number of moles of potassium dichromate used in the experiment.

(1 mark) (e)

From the equation grr en on page 4, determine the number of moles of iron ions (Fe2') that react rr,,ith 1 rnc,i; cf dichromate ions (Cr,O_r-).

(1

GO 012

120201JANUARY lt)

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mtrt)

r

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".'

Calculate the number of moles of iron in the iron salt sample-

(l (g)

rnark)

Calculate the mass of iron in the iron salt sample.

[Molar mass of Fe is 55.8 g moli-]

LS (o

co

(1 mark)

(h)

Calculate the percentage of iron in the iron salt sample.

(1mark)

(il

'J .r!.

The reaction between iron and dichromate is considered a reduction-oxidation reaction. Define the term 'reduction'in tenms of electrons.

O O

,"""""'-""'

o

()

""""':""""'

(1 mark)

In the reaction, Fe2* acts as a re&rcing agent. Define the &mr 'reducing agent'-

(2 marks)

01212020/JANUARY20r9 lu ffil

il

m

il r uI1 [

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(k)

Calculate the oxidation state of Cr

in

CrrOrz-.

(2 marks)

(1)

State ONE precaution that sirould be taken u,hen carn,ing out the erperiment.

(1 mark)

Total25 marks

GO ON TO THE NEXT

012120201JANUARY 201e

IIIItr[UUIf!rfII

l

a'

L

l.,,

-8(a)

the scent of curry coming from her mom's Jamelia is in her IOom Sudyitrg and smells ..Ah! Diffusion at work!,, to herself, cooking in the kitphen afea. ste oinr<s

(1)

Define *re term 'diffirsion''

(2 marks)

(ii)Explainhowthediffisionofthescentofthecurrysthepj{i*lI"theo1 of matter. @ @

i;;;;*j (iii)

S"a:e h'''\\' tire arrangernent Diffusion is a proeess that can also occur in liquids' soliC and a gas of ponl"f". in a liquid differs from that in a

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-9(ir')

Apart from diffsion, identify ONE process that s the particulate theory matter and state OlriE example of such a process.

of

Example

(2 marks)

t

0

GO ON TO THE NEXT

1212020 / JANUARY 2019'

f, E U U'fr [ EII lrEI H! rq rhX Ur ilr

.l

-10-

(b).Jamelia,smomshowedhefthatinordertocookwithcurqyshefirsthadtomixthecurry mixture mixture resembled a chalk and water that the

powder with water. Jamelia ob-served curry mixture was brown in colour' she had seen in class, exceptthe

(i)

State whether the

,--r^- ^-,{water is a suspensro n or colloid' mi$rre of curry powder and (1 mark)

(ii)

..atetechniquethatcouldbeusedinaschoollaboratory

State the MOST aPProPil

to seParate this mixture' .

".

"

".......... i......

(1 mark)

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.i

GO ON TO THENEXT PAGE

0r212020/JANUARY 2019

I

- 11 -

(ii|

Draw a cleartlr hbelled diagram of the apparatus that could be set up in the school laboratory to seprde the mixture of curry powder and water. In your diagram, show the localn of the separated'cbmpone-ntr----

(4 marks)

Totdii5 marks .t

0rl1r0t0

i.\\L-\R\-:

CrO .-

ll lll Illl il

ilil

I rrr

il iil

ONTO THENEXTPAGE

r 3.

(a)

Compound-\isastrargh:-;h;'i''1\Jr'carbonwiththemolecularfomiulaC'Ht'' of and T\\-o possible uses hydrooarbons ll s':;:;e (i) State O\ E 1l'f i'..;ir Con-rPcun'3 -\ Source Uses

(ii)

A' sffucturo of Compound Draw the FULLY DISPLAYED

CO

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o

Structure of ComPound -t

t

2 nrarks)

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a

lill

I

-

,:-

-l

Therrnai and cataivtic Cr:-:. - - j:e \ ery useful processes in the petrocher-nical industrr.

(i)

Define the

ter:

-

tr.i '.-tc cracking'.

(2 marks)

(ii)

state the

imporare of catalytic cracking in petroleum refineries-

(1 rnark)

CO O'r TO THE

I I l, -T{\l ,\RY lr,rtflt

ffi,illt

il1ilIilililt

tr

\EXf P.\t -

r

-i4(c)

converted to B-with the formula CrH,o' can be Another hydrocarbon. comp.ound

Co*po""iA T

u simple one-step reaction"

D:r.',";.tt-a-

(i)

-'

-

-

-

1'-

Compound B' triSPLAYED structiral lbmruia of

€ co

Structure of ComPou.nd B

O o

O

(ii)

State ONE physical

(2 marks)

and Compound B' p'op"ny common to borh Compound A (1 mark)

GO ON TO THE NEXT PAGE I

rI

ffill lllll llll llll

r

-l+(c)

\-.-...-:--,-. r: -.-.---\

.

-

,.-!

can be converted to ,- -.:--:ld B \\tith the formula C-H,.,

C.-::--:.1

-:lj \ ':'. t S'il-l ; --;-:

(ii

B' IISPLAYI strucftiral forrnuia of Compound p.:i l.:- ' - ---' - - ' IISPLAYED Dr:ri Ppjrr ita Pt-ss-r--

':;33f,1-1o11'

Structure of ComPound B

C

O

(ii)

(2 marks)

B' to both Compound A and Compound common ptop"ny physical State ONE

ii

CIO ON (

0I2I?020/]ANUARY 2019

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TOTHENEXTPAGE

- 15, (d)

CompoundA anc in the dark.

(i)

t : :-.:': -:. r B can be distinguished by reacting them u'ith bromine strlutlon

State u hrci: - - -: e rvo compounds, A or B, reacts with bromine.

(1

(ii)

mark)

State the colorn change that is observed when ttre reaction occurs.

(1 mark)

(iii)

\liite a balan;eci chemical equation

for the reaction.

(2 marks)

Total 15 marks

01112020/JANI:Af{\-

-

GO ON TO THE -:

lIIIIIIIIIIIT

\E];I :.

-:-

-1

-16-

Sf,CTION B

'

A-nsrer

AII

Write your reslxlns

(a)

4.

Define

(t

qrc!$tfr)ns in this section'

ir ttc

spaees provided in

this booklet'

E\Cli -' lr.; -- - ;' -' :i-': Atomicaumber

C O

Go

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i

a,\

r,-, ^ I-.i

\F\T

PAGE

r'

tiirt fi [ fl 1] fi 1 I tll lilllllllll

I

-17 (b)

Sodir-rm is a metal i'.

(i)

.-. :r. ,-,:nic

number of i

I and

lilass number oi

Ii.

Draw a dia!r': ,- ':t,ru-the arrangement of electrons in a sodiurn atom.

(2 marks)

(ii)

State the period to which the element sodium belongs in the periodic table.

(L mark)

(iii)

Describe the type of bonding in sodium metal.

(2 mark,

L(-)

(-)ll1:(,)10 -lA\LrAR\-

l.

-

Il llt ll ll Il I llll Ill I ll il

o\ lt) iHE \l \

-

18 -

(c)Sc..li,.ri:..;i1,.-::.::.:]]-:::.].-isodiummetai'-A'C.-i-t;c:li;::eJs..cliurnclrloridesolution . :'i':::lrte in an e1ectrol1''tic cell (Lriir:: i a ':- *lr-1-:-- ; :. ' ''s lr'hett it is tlsed as "'l'' Lt't:.-.:';a i --'- --ll'

De-:-l:-'

'::-- ': ;---- rsis"

(2 marks)

(ii)Writethehalfequations,includingstatesymbols,forthereactionthatoccursat of concentrated sodium chloride the anode and cathode during the electxoiysis solution (brine)-

i"""""""""

Anode

"""""""""""'""

"""""':"""

Cathode

(6

marl

Total 15 mar''

o O

GO ON TO TTIENEXT PAG !

gilllr)iu,r\\L \8.\ I '

rrrrllffillHlllf,ill

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-19-

NOTHING HAS BEEN OMITTED.

GL-)

IITITIIIIIIII

O\ ,

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r

-20-

t.

(a)

CompormdD,CIIG{,GLCOOH,hasaveryunpleasantsmellandbittertaste' D belongs' Name the homologous series to which Compound

(,

(1 mark)

(i1)

formula of compound D and write its Draw the FULLY DISPLAYED structural name'

@ .D

'

O

Structure of ComPound D

(2 marks)

o Name of ConlPt'ur'i

)

(1 marh)

(b)CompoundDt.ea;1...'..---.:.-:..']:clbnrrthesr,veet-sileliinsConrpotrtldE.

tii]I-r':,.'.':-.]..:-]-':.:euuationfortlrere:::-..:.:e:..'eel.i.L-rlTlpLrundDa:1.: -:E

rl mlrL-. i-: 0

1

I :.010 JA\I-\F.\1

lr-r i 9

u

r*r

u ff r{ r [Ir I lll

llillllllli

'.

.

*l' tillr' ' P\uL

l1

(ii)

Suggest the

cmditims for the reaction between Compound D and ethanol.

......--............................ ...............,..

.........,...-..4..

(2 marks)

(iii)

State the type ofreaction that occurs between Compound D and ethanol. ....

]l-j-,-,-.-----ft ---t!+r

i.............

(1mark)

li--:*--, il::11:{--. -ll:'A-l

lL---\rr-:

(c)

Compound D reacts with sodium metal to produce a sah of Compound D afld a gas.

][.F{i Ia:--_-'-l:

(r)

rl- -- -l:

,l

Write a balarced chemical equation for the reaction between Compound D and sodium metal.

-:-_-_---

r-:. -'._-l

I

.trll _ 'T!:: .: -: tr-_-:_: _

t-l_ l_-', ilf: !) L

!i 1ifrf -:.+1-

(2 marks)

'!l- _ J..ll

i,

:-:i

-

+.

-it-.

(i i1

:li:i':

Describe O\--E test that could be used to identifl the gas.

!:.: .lf

li'.r u .** li.:,'.::i r'l'"'

:Li:

(2 marks)

-.i!-.r ': ;l

-?ri-

l--'s*

-.

lln-f=

t+l

-li--a5-

(iii)

State whether the salt formed answer"

will

be soluble in water, grving a reason for your

-'lt-:!-qt .l!-----.

l:-,_-_---:

'll---ri

-

-+

.-

rj.l

.t _-i

(2 marks)

',

t.- .

Total L5 marks

:

'i.'li. il'i.-,,

... .

'[. ,;] ' -tjj-,."'' l-..' ' -.'.,1! -1'rrf.ir lt.. -'1,,

i,,

jrl

-,r' ' 'li', lf.- .,

..

-r-.Ul: -

ii- 'Y_1 '-rl r- ,,..'a

'.,]

::-l

ii-_::-_---.,1i. -,..a.

'li^r-t_-

GO 01212020/JANUARY 2019

&ffilll ltit tHHflIilIlr

O\

TO THE

\-E\I . ' I

--':j

--l-

r 6.

-1

' _^!- -

(a)

' rmoncl and graphite -- -l"Jl'il.":;'-";

'I;;';

:;,',:.]'ii'i.:x::= ,:-,. rlt

.,rr. Q\E "' ;. .

many and is a main compouent in

"'-----''

'u'bon

dioxide gas

irom -eraphire' Ciamonci differs physicalh

(ii)StateoNEsirnilaritlbenrgendianrr,lc].anderaphiteotherthantlre-vlrotlrcontain cartron.

@ co

ii;;;-; (b)

monoxide' whicl, can silpply of ox-veen to form carbon Carboir call react sith a liuiteci health' ne gativel,v affect hltrnal-r formatioi,l rnclucling state s-vmboIs. to shou,.tlre a balancecl c}remicat eqttation,

(i)

Write of carbon monoxide'

(3 marks)

(ii)

StateTwoe.ffectsofcarbonmonoxideinhalationonthehumanbody. - .. ..-.

!......,....'.'.-.......""."""'

,

O

o

(2 marks)

sr-:, r r\ TO 0 12 I

2020/JANLiARY 20 19 !

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