CANDIDATENAME

SUBJECTCLASS

NATIONAL JUNIOR COLLEGESH2 PRELIMINARY EXAMHigher 2

I

REGISTRATIONNUMBER

'--- -----.J

CHEMISTRYPaper 1 Multiple Choice

Additional Materials: Multiple Choice Answer Sheet

Data Booklet

9647/01

Thu 19 Sept 2013

1 hour

READ THESE INSTRUCTIONS FIRST

Write in soft pencil.

Do not use staples, paper clips, highlighters, glue or correction fluid.

Write your name, subject class and registration number on the Answer Sheet in the spacesprovided unless this has been done for you.

There are 40 questions on this paper. Answer all questions. For each question there are fourpossible answers A, S , C and D.

Choose the one you consider correct and record your choice in soft pencil on the separateAnswer Sheet.

Read the instruct ions on the An swer Sheet very carefull y.

Each correct answer will score one mark. A mark will not be deducted for a wrong answer.Any rough working should be done in this booklet.

This paper consists of 19 printed pages and 0 blank page.

NJCIH2 Chem/01/2013 [Turn over

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Section A

For each question there are four possible answers A, S, C, and D. Choose the one youconsider to be correct.

1 Which one of the following represents the configuration of the three electrons ofhighest energy for the ground state of an element in group III?

A 1S22s' ~ "S-;, r \ o,k, ,,,,vs+,, (O"{ij,,nJ,-M

S 1s' 2s' 2p'

C 2s' 2p2

® 4s24p '

2 The first ionisation energies of twenty successive elements in the Periodic Table arerepresented in the graph.The letters given are not the normal symbols for these elements.

o

ofirst ionisation

energyIkJ rnor '

A BCD E F GH~ JI. Jil. iii Y 1I

I J K L M:ill :1 j[ f1l

element -

o

NOPQ R ST!£. Y ill. 'iffi ~ 1L

Which statement about the elements and their compounds in this graph is!!£! true?

A Oxide and hydroxide of element M are amphoteric. "liP ."5 ' M ~05 d {I({ort )5 '''''' r~ rt-"ri C

® Oxide of element F has a giant covalent lattice structure. Nv , (0,,- 1'< ;::;'1'1.<.. ~'ol" .. ....kr,

C Elements S, J and R are in Group 0 of the Periodic Table ,~e--

D The second ionisation energy of K is larger than the second ionisation energy of L. i J!ok -"" 6 J.. .,k/W1l\'!.. ).",1 IE ...., .!\..«.. -""'....'0e {i.,,- o..t...r e,- ='"/ .,,-(..s ~!.at- t """-'(Rl '

r _" hfbJ '" r,r"'- oJ k <I<~ "'''''L - G 11- .d.<"."J , hJ I e jh~ ,"<. """,~ .. ""'- .s c( u v '

r 'b J - I -- I '~='=? llA?1 r<2. f,A.fi'~ • 1.ll.JwP - .

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3 In an experiment , a beam of protons was passed through an electr ic field of constantstrength. Analysis of the deflection occurring at the electric field region revealed anangle of deflection of 12° towards the negative plate.

12°\DL =::::::::::c:::31:c====-=protons

I+

Under identical cond itions, a beam of particles , Q, each having 24 times the mass of aproton , was deflected by an angle of 1° towards the positive plate. ~ Q. is, -veto (1.."'j~.J

J,~What is the overall charge on a particle of Q? -1- of JJ1<J,b", 0< ",,= s

A 2 .1'''J'' I n , '+ fiv n""j-;,,, s =-, )( =12 ' q """t =, ~ M n..-U: J 7" l L.,.......,.2.:.:::Je J-

8 +3 ~'" _ J,"'j e o """",' 12-~ f ,,·,ihl e Gl J ~ - ).'t '" I

C - 3

® - 2

4 Use of the Data Booklet is relevant to this question.

A typical solid fertiliser for use with household plants and shrubs contains the elementsN, P, and K in the ratio of 15 g: 30 g : 15 g per 100 g of fert iliser . The recommendedusage of fertiliser is 14 g of fertiliser per 5 dm3 of wate r.

0.05 mol dm?

0.42 mol drn?

0.75 mol dm?

0.03 mol ern?

8

oC

What is the concentration of nitrogen atoms in this solution?. . , .. '''J° h·" . " f' . K ... 1'>6 . ",°9 .relr I aOa~ IS<e.r ,) IV · . - (J

f'" 14-3 f"fil;~~ J M .-&! crf N =t;:" "I.J·... )d( I~ S d,} \1z,o J r d ..._ 8'+ I'-) .J.-

rY'\ e: cr " _ I- ~ )l.. 14-.0I 11Co

z o-IS .y'I ol

= o - I ~- r • ~5 =- c . D ~ ,~Jl ,;~ j

NJC/H2 Chem/01/2013 [Turn over

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5 0.200 mol of a hydrocarbon undergo complete combustion to give 35.2 g of carbondioxide and 14.4 g of water as the only products.- - --

An increase in both the total number of electrons and the nuclear charge

An increase in the total number of electrons with the nuclear charge remainingconstant

A constant total number of electrons and an increase in the nuclear charge

A decrease in the total number of electrons with the nuclear charge remainingconstant

A

B

, (" v\ ~ ~.J;" h~ <I "" "" .. bo.., : c. ~ H- O- d;t l,)O .' o .~ : I • .b

:: I : 4- : '6 /1 H ",, <.'- ,C4H ~/1

The ions p3-, S2- and cr have radii 0.212nm, 0.184nm and 0.181 nm respectively.I~{ I ~ ;: 1&;: ( ,'5odo.chv ...ic..) hJ r ,",,+D ~ "<> 1' «.,~ "f -h 1.3. I.. .,« .

Which one of the following correctly explains the decreases in radius going from p3- to

err => Sf<,"",- "..,. 1z W "' v ,,," -&"'zfo 11 f dfl l.<~cI

c~<. .

What is the molecular formula of the hydrocarbon? 3'> ·2 ll- Im ol .f C ~" hjdNC~\''''' ~ ,"",vi 'b (0,- ~ Lf4. ~ o · 0 M D

,"".1 of H ;" lojcl,..".." ,L.o" :: ~,c ~,~ 'h 11...0= 2 'I- I~" I· {"o M Cl

I ~ . D

@D

A

B

C

®

6

Which of the following species does not have a bond angle of 1200 around the centralatom(s)? CJ. ILO" - ' ."0/ 3 b~J r~'''' , 0 .J,..~ r~'r­

...... 'AQ.- Gl(;. /A

B

©D

7

A

®cD

8 In which process are hydrogen bonds broken?- -I . . 1_\ 0- \1 'o\J~ bo/'Ie-fa

2H20 (I) --> 2H2(g) + 0 2(g) ;" ' 0\'- "",.u«{j. ..... -"'- "" \".." I rt nl:<lt9, ·,.,k .... <1 e~ rI- b.~Js

CH3CH20H(I) --> CH3CH20H(g) v"i'o t1.>"'~ .-y 1 v v " (J

:=. =NH3(aq) + H20(I) --> NH;(aq) + Ol-F(aq)

CH3COOH(aq) + NaOH(aq) --> CH3COONa(aq) + H20(I )

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9 The equation below represents the combination of gaseous atoms of non-metal X andof hydrogen to form gaseous X2H6 molecules.

2 X(g) + 6 H(g) - X2H6(g) LlH = - 2775 kJ mor"i ~

The bond energy of an X-H bond is 395 kJ mot" , I\-X-;;< - \1~ ~

- 202.5 kJ mol"

+202.5 kJ mer"

+405.0 kJ mor"

-405.0 kJ mor"A

B

C

I ' ..i; '"~ N ",'c.d-, tL ' rc~"" q1 <./ , ,1,,-f1e.eJ f'\rr k j 'CV\ n .:)o'\A L- J 0 ~

7} '/•.~-Which of the following statements about lattice structures is co rrect? LE eX t. • )

l'" '-® The lattice energy of an ionic crystal tends to be large if the sizes of the two types

of ions involved are small. j ~ , ~"'<..l I-E. c:, (,~ .,. c )

®

10

B The particles occupying lattice sites may be atoms or ions but not molecules .

C The forces holding the lattice together are so strong that the particles occupyinglattice sites are held stationary.

D The lattice energy of an ionic crystal is always larger than that of a metal.

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11 The diagram shows the Born-Haber cycle for the formation of magnesium fluoride.

Mg(s) + F2(g)A\\f

~

1b~at(rAj) IgG.f Fz"V

<315 1" ) Fl!J). LItlE orAa

t;H, ~ IE 1"'0 t;H2 tt:.~ (l.t")ofF

'"Mg2+(g) + 2F-(g)

t; Halm : Enthalpy change of atomization

E.A : Electron Affinity

MgF 2(s)

I.E: Ionisation energ y

B.E : Bond energy

Which of the following represents the correct energy changes, t;H, and t;H27

A

B

c

@

t;Halm of Mg + 1st and 2nd E.A of Mg

t; Halm of Mg + 1st and 2nd I.E of Mg

t; Halm of Mg + 1st and 2nd I.E of Mg

t;Halm of Mg + 1st and 2nd I.E of Mg

2t;H almof F2 + 2(1st I.E of F)

2(B.E of F2) + 2(1st E.A of F)

2t;H alm of F2 + 2(1st I.E of F)

B.E of F2 + 2(1st E.A of F)

12 25 % of a solution of ethanoic acid was converted to ethanoate ions by reaction withsodium hydroxide solution at 25 °C. ~ w.>c.J h'(j 5b\", £.l.~ "7S}v d bu:t """'d} C(u',Q

~ ).};'7. WJ CO ,:" I\l~lWhat is the Ka of ethanoic acid at 25 °C given that the pH of the solution was found tobe 4.287 - U '..Jt]

A 1.57 x 10-4 rl1 ' f~a t" I~}" ~

B 1.31 x 10-5 4 ·)& • f'l<"r- + !"J , o l~ )

© 1.75 x10-5 f'l<~ ~ 4:1-~ -IU .. (t)

D 5.24 x 10-5 = 4 .151

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13 The solubility of iron(II ) carbonate in water at 25 °C is 5.59 x 10-6 mol drn'",-

5.59 X 10-8A

What is the numerical value of the solubility product for iron(II ) carbonate when .dissolved in a 0.01 mol dm-3 solution of iron(II) chloride at 25 DC? ~f u,J,C"j~ ..Iv> <.t. fe"1 ' ......AI'<)

~ <a ..... •F"<.(U;, ~ k ~' r ( 0; - 3-c n l -

,£.5 '11-11;& £ .s-ej;(./ O ,.....,oJld""

8 5.59 X 10-10

C 3.12 x 10-9

@ 3.12 x 10-11

"=/ ,"'., """-'-'hTime Total pressure in Pascal

At the end of 10 minutes of reaction 600

After completion of reaction 400

14 The following data is obtained during the first order thermal decomposition of

2A(g) ~ 8(g) + C(s) ='? -l11. ,~ is4 00 f (S,In '-'- ).~J\ ·1 A c"",~-l,tf~ \,..S) 1

at constant volume and temperature '~ ",-,J IJ =. ).}> "' 0-, ll"Ou p", )

What is the rate constant for this reaction in min'"?

A cannot be determined due to insufficient data

8 0.0346

© 0.0693

o 0.138

NJC/H2 Chem/01/2013 [Turn over

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15 The curve Y and the value Ea represent the distribution of energies of the mo leculesand the activation energy for an uncatalysed gaseous reaction.

energy

curve Z

curve Y ("",~..J)number ofmolecules

with energy

D

c

B

1 1 IV e, W

What is a possible outcome if the reaction is catal ysed? :Y' 1:.... (v....>.",J , ~J no> c.k~ Iv ;:::E1 J"'" r-J-'+ J.u"

@ The distribution of energ ies will be given by ~urve Y and the activation ene rgy by "L:;o dva lue V. ::leo - Iu,•ar e". a-J ...." ,w<. didnb.di"" ,-<" v<. . s .''0 7

The distribution of energie s will be given by curve Y and the activation ene rgy by ,\j~+,.,h..J,;',W""'" •

value W.

The distribut ion of energies wi ll be given by curve X and the activation ene rgy byvalue W.

The distribution of energies will be given by curve Z and the activation ene rgy byvalue V.

M';(J) 1" o>.-u)16 During the electrolysis of molten aluminium oxide to prod uce aluminium, using graphite

(carbon) electrodes, two consecutive reactions occur at the anode, each producing adifferent gas . At- a.~ -tJ.- - :>-'>0 +:J. i o .N . r-~ a,

) 0 -::::;~_ &.

How does the oxidation n[.J mbe r of oxygen change in these re~c;o~~? --';> co>.. 0 , N . { ~.:1 >-

A decreases by 2, then increases by 2

® increases by 2, then decreases by 2

C increases by 2, then decreases by 4

D no change, then decreases by 2

NJC/H 2 Chem/Ol/2013 [Turn over

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9

2;.,J.T",Je ~ Zr. -0 '7lV c/: : le ~ G.". -t"0'3l1-V -cr-

CG,L' J .j, , pD<ODb rv<f"i'M .<l.if i5 1J1 ~ , c.. I:,;; -M.E" E2and E3 are the emf values of the three galvanic cells I, II and III respectively. ~ ~<aI "'"

o ~ ;,w"., W{-<.t1l JZ.,!...<iih WF-all =') <', -c, E~

Celli Zn IZn2+ (1 mol dm" ) /I Cu2

+ (0.1 mol drn'") ICu '£,Cell II Zn IZn2+ (1 mol drn' ") /I Cu2' (1 mol drn' ' ) ICu E2- ';:' +0 .3~ - (-0 .-,6)Cell III Zn IZn2

+ (0.1 mol dm-3) II Cu2

+ (1 mol dm" ) ICu E3c.z.-H ] t., ~1"'" r",:h~ ~ s 1..11, Ll1S)"£'(r.,.,,,,,, - v<-

Ail the statements are frue excep t => "'-e-:o.U -t-=';> ~ 3 ? e 2-

A The emf of the th ree cells are of the order : E3 > E2> E, ~eo.

®c

o

The polarity of the copper elect rode is pos itive only in cell II and III. No.IJ (/l hi..... L"\"'.r -Ah, 4.a c...~r i~ ,.. ,tu~..J J, c.... .

The..colour oille solution fade~ in one of the compartments of each cell.

Electrons flow from the zinc electrode to the copper electrode in all the threecells. tl to - ve (e<iJ'" ~Jf-uJl) (+~) - ,..d.uJi\>/"\ ''''-If-edl

18 The information relates to element z.

• Z is in Period 3 of the Periodic Table.• Z has a lower electrical conductivity than Mg.• A Z atom has a half-filled subshell in its ground state. ~ ".rr B > " trf D

• Z forms an a.9Qic_Qxide on e2$R,osure to_air. -=';> ~ ut Pr

What is Z?

A Na N 4L V ls (:\. /,,,,,'l.. ~ ik

B Si fl'/aJ ,>,2 31' >- " .,I- h,JH;JI~

s h ,Jf-~II<J ".J"kU; P't 0~ Ir,c. , ao+< " co.L<. ".,.., et....o© P LNd 3s

2!.t-O Cl [ NeJ 3"'¥ n...l ~.Jf-h1l.J

B

C

194·6 -to 2. e l

Sulfu r is converted to SFs by fluorine, to SCb by chlorine and to S2Br2by bromine.Whi ch trend does this information best provide evidence for? .~

o . LA the trend in bond energy: C12 > Br2> F2 S -t- sF. -~ SF{.

~the trend in electroneqativity: F> Cl > Br v ;> . ~~ + U l. -~ sC(1.

the trend in first ionisation energ y: F > Cl > Br ~

® the trend in oxidising abili ty: F2> Cl2 > Br2 ). ~ or e, - l;>s s-L " >-

NJC/H2 Chem/01/2013 [Turn over

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~ J-r".L -bL." ''l'f'"aJ... Ol> .J $DOc. Ce . ""N<" 41"""{ 'J'> ~cr.J20 An enzyme is completely denatured at 50 · C. A fixed concentration of this enzyme is 5'>0<:-)

added to a fixed concentration of its substrate. The time taken for completion of the :. " .,+ D .

reaction is measured at different temperatures.

Which graph shows the results?

A 8

time takenfor completionof the reaction

10 20 30 40 50 60temperature I ·C

time takenfor completionof the reaction

10 20 30 40 50 60temperature I ·C

10 20 30 40 50 60temperature I CC

time takenfor completionof the reaction

time takenfor completionof the reaction

D

/

10 20 30 40 50 60

temperature I · C

CeH,e + 24 NO --> 8 CO2 + 12 N2 + 8 H20

CeH,e + 16 NO --> 8 CO + 8 N2 + 8 H20A

B

- "-<120 ""'- ~r",ek Y""""r. b ......... -bJa., '" .,j R"i .

- .", J<.; 1", QftLJ""" dJ.J, dud 9 f"adv'iI:J i) -hM,-+.J:.""., 1" .

One of the react ions taking place in a catalytic converter in a car exhaust system isbetween !Jitrogen oxide and octane (unburned petrol). The products of this reaction are

non-toxic. '-,} ..., <t...~ '" Nz, '-...,;. c>x,J,is.,.,! -h. (.0a, -t- 11,,0 =9' n.oj' A J flat c.

Which is the correct equat ion for the reaction? ""de d..... ~~ iJ '" d-z<'"i s G?rt ,~ . (C"Hy " ,,. )

f='> flot i3.

21

C CeH ,e + 17 NO --> 8 CO + 8 Y, N2 + 9 H20

(@ CeH,e+ 25 NO --> 8 CO2 + 12 Y, N2 + 9 H20

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tc..

•

GH't c.H>-= Ql>.- Cti3 Qi =CtI,.22 The products obtained by cracking an alkane , M, are methane, ethene and propene.

The mole fraction of ethene in the products is 0.5. - -

What is the identity of M?

A CeH'4®C

D

~ b/hilic me chan ism while alkene

iT bonJ ~

=9 ...."'",m

It 'I ;:I IIt -,-- G- c.. - It

J I 1Ii C. \-\

H-I .....H...

5

4

6

oxygen is mo re reactive than carbon

the different lengths of the double bonds

the relative strengths of the double bonds

the electronegativity difference between the carbon and oxygen atoms in thecarbonyl group

3A

D

B

©

A

B

C

@

23 What is the total number of isomers (inciuding stereoisomers) for an organi c compound,C4HgF? - - "r!i·,·J I u1.-t-z,M -

H H 11 ~ - 11I \ 1 I I'l, ~ I' \

H -('-C- <:'-('- 11 _ <:..- <:., - <:.. - <:- - '1I I I I " I I'" \ I

11 Ii H It It It H H L;).."rll CcJ ~O~)

,t 0,-24 What causes carbonyl groups, C=O , to react by a nucieo

groups, C=C, react by an electrophilic mechanism?

NJC/H2 Chem/O 1l2013 [Turn over

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4

VI~ I;~ <::"or!

2-chlorobenzoic acid r::.W 1)

,~·t.-'ot1cyclohexanol / \... u-

'-..J °H (14'aI.lt "c..'d.'t.) 9 not A ) nat- C .What is the relative order of decreasing acid ity of these compounds?

25 Consider the following four compounds.

1 2-nitrophenol ( "9(01'1N O"

2 benzoic acid

3

Most acidic ~ Least acid ic

A 3 2 4 1 )I

® 3 2 1 4

e 2 3 4 1 x

D 2 3 1 4

26 A product P isolated from a naturally-occurring source is established as having amolecular formu la of CaH9N03. It possesses a chiral centre and it forms a zwitterion .

.\ \ . ~ h~ " .:t-l-I - Co,.rl •.JWhich one of the following structures could be P? ""Y _'" .•,,,* c, ncr D - ,W L 0wi'~

.:. .,at i3 .

HOe

eOOH

D

e OOH

NJC/H2 Chem/O1l2013 [Turn over

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(,- or! j"'''f f

CH3

CH3 ~ o>\-...,-

santonin

27 Santonin is a drug that was once widely used to expel parasitic worms from the body.

CH3

When santonin is first treated with warm dilute H2S04, followed by cold acidified KMn0 4,X is obtained. (l'.'Jd~ltlj: of ~.",,) ( ~aa;"., 'b CF Co .j.r d,ol )

How many atoms of hydrogen in each molecule of X can be disRlaced with sodiummetal? => - 0 t-I .j""-r'A 2 B 4 C 5 @ 6

Which is the most likely molecular structure of F?

A

When an isomer F of molecular formula C4HgBr undergoes hydrolysis in aqueous alkalito form an alcohol C4HgOH , the rate of reaction is found to be unaffected by changes inthe concentration of OH- ions present. =) 2M> ev.I..J ~ · ' .-t . OIi -

cv- ,.t- (JV"J....r- ...... r · t.. . ~ rl" 13Y'

-=-> Sol I (')<,""

=7 3 " «.1-

28

B CH3CH2CHBrCH3 ,,) ' I?'I.

C (CH3hCHCH2Br " (?.'f.

@ (CH3hCBr ?," R:f.

NJC/H2 Chem/D1I2D13 [Turn over

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----;.~ Q

What is the structure of Q?

29 The first stage in the synthesis of antipyrine, a drug used in reducing fever, is thereaction between compound P and phenylhydrazine.

C~e2CH3 + <O)-NH\ A2)P PhenYlh.Y_drazifl/

<0) NH~CH3CCH2C02CH2CH3

B

c

D

NJC/H2 Ch em /O1l201 3 [Turn over

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30 The reaction cond itions for four different transformations are given below.

Which trans formation will occur under the given conditions?

OH 0 ,.,..n~ ~s Q!3-Wa .a.... OCO CH

~o CH3COOH( , conc H2S0 4 f'k~~~1~~ 3

A ~ heat lQJ

B

H...o wo-lJ ( =M! i=<g".~ -lo~ CH3

__B_~£L-,,(aa_qq_D),--Fe_B_r_3_. ~Br

30°C lQJ

©

D

Br~OH(I)

Br

-

NJC/H2 Chem /O l /2013 [Turn over

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Section B

For each of the questions in this sect ion, one or more of the three numbered statements 1 to3 may be correct. Decide whether each of the statements is or is not correct (you may find ithelpful to put a tick against the statements that you consider to be correct .)

The responses A to D should be selected on the basis of

A B C D

1,2, and 3 are 1 and 2 only are 2 and 3 only are1 only is corre ct

correct correct correct

No other combination of statements is used as a correct response.

31B

Which of the enthalpy changes of the following reactions can only be obta ined byapplication of Hess ' Law?

./ 1 The hydration of anhyd rous copper sulfate to form crystals of CuSO•.5H20. -':'~ .-h..J/ 2 The formation of methane from its elements. - Uv>"'-'t /,e. -Ji,""J Q'rt~ . f

3 i- The combustion of glucose , C6H '206. - ~ ~e ~w,,~ \'0 "",r.. ; ""«0,,«, *"1 N1.. ""L.­~~ <1 it' ~v<- .,. I,., ..J -J...,~ I' /q,o.~v{) SlJ .1,..0. p

steel electrode

32

C

Strontium metal can be obtained by the eiectrolysis of molten strontium bromide,SrSr2, using the apparatus shown in the diagram . Sr'"t BY

.; ~di~".J et~d.,,~e).J- ecJt..oJ..L .J ""o~

graphite electrode \

moltenstron tium_~_

bromide

atmosphere of/ argon

~ molten strontium

I--O!:F--J

theat

Which statements concern ing the electrolysis are true?

1 "J-.

/ 2

./ 3

193 coulombs of electricity are needed to deposit 1 x 10-3 mol of strontium atoms

at the anode. s,- Is; ~O<I'kJ ,j It". c«tf..ocL.. (",j- <Mod.>-) 9 iW...~'~ c,;;

The region around the graphite elect rode turns yellow - orange. ). ilr- -" Cl<~ -t- <-q.-<L:«: JOb g ,2. t;::; "",,J .

Without the atmosphere of argon, strontium oxide would be formed.

NJC/H2 Chem/O1l2013 [Turn over

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17

When light is shone for a fixed period into a solution of CH2ICH21 and I, intetrachloromethane at 1aaoc, the following reaction occurs:

Relative initial concentration Relative lightRelative initial

experiment bt rate of formationC21'4[2 (NW I Zvu intensity

ofl22 '''IIc:Ur1 2 , 1 4 2 ..,

2 2 lI~ 1 1 1~ ..

1- t-

3 1 1£ 1 , )(2- 4 1"'\ no cJ,,,,,,4 1 2 ': 4 1 ~

What conclusions about the reaction can be drawn from the data in the table?

The rate of formation of iodine is proportional to initial concentration of C2H4I,.:Jeo -: let wd>.r... , t G,iI...J ",

The rate of formation of iodine is proportional to " (light intensity).

Iodine is not involved in the rate determining step. 'IoU: -,' Z eN w<h.r "" t :r 'z,

34

C

In black and white photographic film. light converts silver chloride into metallic silver.After the film has been developed. the unexposed s ilver chloride is removed byreaction with s..Qdium thiosulfate to produce a 'fixed' negative.

The process can be represented by the following two reactions:,q -l 0 0

2AgCl -> 2Ag + Cl 2 I~ ..-

AgCI + 2Na2S203 -> 4Na++ ct:+ [Ag(S20 3hl3- )l'+~ 0,0 (""W,lJ,.

Which statements about the reactions are correct?

Both reactions involve a change of oxidation number. N.,J fu tk J..J "'''' ~ iW-or J. c .

The role of sodium thiosulfate is to make the silver ions soluble. 'tea j ....-r: ,"' ~ .fZ.,........J

Both reactions have positive 6S values. Y"J , bcl-l, "'" ;-.,,,~ t ,v, (\O. •~ r":35 Consider the species in the following equation.

A [Ti(H20 )613+(aq) + 2Cr(aq)o,*,I.u!.,J

Which statements are correct? J k ;'"( ba-ofh o ... J,ct-I-.. ~';1. AU J-- W. f' t , _ fh.,-J =I oN'- FC«Y "("'~)

./ 1 Water acts as a Lewis base.- .L:..... , ,,.;,.. ct.u~ ""' . V"'-~, J -. .- . .

./ 2 The complex ions are both octahedral. (~h ~ ,,,-.,,,..t; ,,odi ,,~ Ito . (, )

V' 3 The [Ti(H20)613+ion can act as a Bnmsted-Lowry acid. '!eo . H~l ~< d.m<;l;l ,f Ti

Hf'lc'rl1tD

_ _ H _ 1., (...to ... b MV") "ei ~\J,o"'; :-i ~ 1D ",fu~;,,4'" 1ftL\ ; <.tJ ~o)b1 ~ LT;(\1...., \ -bt1] T ilt r n v , ';-Ito,. -r;I( ) ",,'J.,~ .f ...J<.£«< ...~ ..... 0' •.• . " '1

NJC/H2 Ch em/01/ 2013 [Turn over

18

The responses A to D should be selected on the basis of

A B C D

1,2, and 3 are 1 and 2 only are 2 and 3 only are1 only is correct

correct correct correct

No other combination of statements is used as a correct response.

D

36t-Ij <r!. ~ e.r:

J

Solid s W, X, Y and Z are compounds of two different Group II metals. Some of theirappli cations are described below. .

~ h<.a v lUjk "" p' (ra. .mr-l-d-c~J wd-I€'i')• Compound W is used as a refractory lining material in kilns. P(1)~\ci M,j0 '

X P""~~ CAW"• Compound X is used as a building material. It can also be heated in a kiln to form

compo und Y. La. CD3-~ &0 -r- (o'}..

x Y ( .Q;Mlno1 :?) l' rH "h <<1\ 1.• When Y is hydra ted, it forms compound Z which is used agriculturalry to treat soils.

C""O ·I- \1LD~ <:",(Dtl).. .. \ '1) lZ-)

Which statements about these compounds are correct? , Go. .lllt <t HI,:) I'Ij o(I.<I)' ":',3.",,1 MjO+"~Ht_M:t+H,,o I ~of' G.tD.<C'<)' -;;;;;:;- M IL (O. t = -> Ca. \ (~o

/ 1 More acid is neutralised by 1 g of W than by 1 g of X. <;;,a aMt 0-1' \1\1. > "",tof .X d I '-~ MQore,. ,",,,,--J IS: ,u..u.1v-....c. '-~ ~j W .

2 y.. The metallic element in W reacts with water more qui ckly than the metallic ' k,element in Y. lilA h"" M r,<n ..il1-- (olJ 1-1 ,,0 (<M~ ",mnw.rk ..<kG''''') . '( (=Cn ) o-<u<-h H O' {; 0

v ";t\A <. leI ri...o.3 'I- Adding Z to a soiljgcreases the pH of the soil. t:.",:0 t rH '1> sa,l (,JbJ;~) .

Z • Ca.(CH)~ ~ .-1W",- <tl,,­

9 t r'' p";I .

37 Cyanoh ydrins are useful intermediates in organic synthe ses. The y can be made byreact ing carbonyl compcuncs with hydrogen cyanide.

-t- (., ,,.0 ~.I.L .~;d.heel -J. G>rb" /f"- A«-.I>

(",J rr ) 1M'+,..J,u...d+> G-T .

( i-\0 "",,)CH3Cf@H 3 + Tollens' reagent

~.....

Which statements are correct about the reaction of propanal and hydrogen cyanide?

( clJ.d'jck.J llu-lo""') 0'" ch ~/ 1 Propanal reacts with HCN at a faster rate than prop anone.YJQ . flllil,~ "" . ~C< W

\~''-'o.CIt. Uf >-... (J, c .

Propanal reacts with HCN to give a racemic mixture.'! "" <;-7t 0 I e-, r - "tto d<. ~11 -...... PCoAov ==/ ,- to rc..- -

.J.>ov<- (J'< kLo", ( ' '''''­The product obtained from the reaction can be dist inguished from propa nal by l,....{ d"", ...Jwarming with NaOH(aq). CH, (H\::. Ul3 Ci' .. ~ r: ru u>~-'(,::::'.. 0 " u ~

/ c-cH ~ I . -Jv~H / \ ~DIi nN~ .en", "'0 .".,jt. I-l«OH) H ( N ----...",.

Wh ich pairso.9Ueagents will react together in a redox reaction ? ( t1 3 W L-f rl 0 ti- It -- 0 ~ -- l. - I -I (o~ N c,+

./1 CH + Cl - ;> Oi~Cl -;- Ii GL4 Z f4.et !l .....-.:tf

/ 2

./ 3

38

B

NJC/H2 Chem/01/201 3 [Turn over

19

39 The compound shown is a hormone produced during preg nancy to suppress ovulation.

D

CH

CH3

C=O

.). "t"J.L

Which statements are correct?

1 Wh . h f>J'llk 1:1, Ul].~=-'" ~"f II au." .[f". b d./ en reacted Wit a a Ifl'e aqueous Iodine, a ye ow preclpl ate IS 0 serve ..-.d"Jiv,.. cf \uh.tuI.. h. ;1 0..1" . t~= Non w;n.. <.= c)

2 'I- When reacted with LiA/H4• the product formed has 3 carbon atoms convertedfrom Sp2 hybridised to Sp3hybridised. No· On~ ~ C "' ~V<I' t,,- .l .

3 )( When reacted with an excess of hot acidified K2Cr207, the product formed doesnot decolourise aqueous bromine . b,c;&,dlb., '1 ,)"alc. 6 \:.R.~

r~dt- dill h.,., c.:c.. ..-<\ ~") C"' N.n w ,'ti. c.: c.)w.\\ cU..u,;.\.O.....-is e, "Ibf'). .

•in acid medium

warm( hjd ""\~I" o(uh"r)

+3 ~

Which reactions produce an organic product containing 180 atom ?

./2

40

B

- End of Paper-

NJC IH2 ChemlO1l2013

20

SH2 Prelim Paper 1 Answers

1 0 11 0 21 0 31 B

2 B 12 C 22 B 32 C

3 0 13 0 23 C 33 A

4 A 14 C 24 0 34 C

5 0 15 A 25 B 35 A

6 C 16 B 26 A 36 07 C 17 B 27 0 37 A

8 B 18 C 28 0 38 B9 0 19 0 29 A 39 010 A 20 C 30 C 40 B

NJC/H2 Chem/01/2013 [Turn over