IChO-2013 Theoretical Official Viet Nam Version

8/10/2019 IChO-2013 Theoretical Official Viet Nam Version

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Face your challenge,Be smart


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(eneral )*rect*ons

- Write down your name and code number on each page.

- You have 5 h to fulfill the tasks. Failure to stop after the S!" command mayresult in #ero points for the current task.

- Write down answers and calculations within the designated bo$es. %ive your workwhere re&uired.

- 'se only the pen and calculator provided.

- (f you need draft paper use the back side of the paper. (t will not be marked.

- here are %+pages in the booklet including the answer bo$es) *over Sheet and"eriodic able.

- he official +nglish version is available on demand for clarification only.

- ,eed to go to the restroom raise your hand. You will be guided there.

A &TO- * b kl i h l d / l0 l


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-hys*cal Constants, n*ts, Formulas an. E/uat*ons

3vogadro4s constant N3 6.7221 1728mol1

'niversal gas constant R = 9.81:5 ;?> 179m


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-ro0lem $1 &2ng m3t l45* 6+ 7o*nts8

Guestion 1 2 8 : 5 6 otalHarks 2 1 8 5 6 2 1>

Sng duy nht c th git ngi trng !"t ph#t $%n

rIn cJc tKng cLa MNi dOPng vQ biRn c trT lOUng lVn kh metan tXntNi dOVi dNng cJc hUp cht mZt lOVi MOUc g[i lQ metan hydrat.

,hTng nguXn d\ trT nQy c thR MOUc khai thJc vQ ph]c v] nhO m^tnguXn n_ng lOUng) nguyIn li`u cho tng hUp hTu cP. uy nhiIn) cJc

nhQ khoa h[c Mang rt lo lZng v kh n_ng phn hLy t\ phJt cLahydrat gy ra bi s\ t_ng nhi`t M^ trong MNi dOPng. ,gOi ta tinrng nu m^t lOUng thch hUp kh metan MOUc gii phng vQo kh&uyRn) MNi dOPng s m lIn nhanh hPn do hi`u jng nhQ knh) tipt]c thc My s\ phn hLy cLa cJc mZt lOVi. o s\ t_ng nhanh cLa&uJ trnh tNo hn hUp khng kh metan vQChoc s\ thay Mi trong thQnh phKn cLa kh &uyRn)tt c cJc sinh vqt sng c thR b tuy`t chLng. Bin cnh ngQy tqn th nQy MOUc $em nhO lQ m^t

khu sng dNng mZt lOVi.

Sau khi phn hLy cLa 1)77 g metan hydrat c thQnh phKn c Mnh 25 * vQ Jp sut kh &uyRn171)8 k"a0) 275 mE kh metan MOUc gii phng. 'pon decomposition of 1.77 g of a methanehydrate with a fi$ed composition at 25 * and atmospheric 171.8 k"a0 pressure) 275 mE ofmethane is released.


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+nthalpy cLa &uJ trnh nQy bng 1?.:? k;


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r li

H^t nguXn methane hydrate lVn tXn tNi dOVi MJy cLa hX aikal) hX nOVc ng[t lVn nht ,gavQ trIn th giVi) M MOUc phJt hi`n vQo thJng ? n_m 277> bi cJc phi hQnh tQu ngKm Hir-2.rong thi gian Mi lIn t M^ su 1:77 m mu methane hydrate bZt MKu phn hLy M^ su 8?2

m.

5. Jc Mnh nhi t M^ trong hX aikal M^ su 8?2 m. +ntanpy cLa s\ nng chy nOVc MJlQ 6.71 k;


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8/38

"hKn tr_m hemoglobin dOVi dNng @b!2tOPng jng vVi hQmlOUng ban MKu cLa @b0 lQ hQm cLa thi gian. %Nch cho biRuth s\ kt thc phn jng.

Figure 2a from the original @ill/s paperR& Hi''& ()yg*n prduc*d $y i+'at*dch'rp'a+t+& , -rc& R& Sc& ./ 0121/ 3& 045/ pp& 0146407 0

8. a. hnh trIn) OVc tnh t l` mol FeC!2khi phn jng kt thc. =hng tnh Mn phKn sZtc trong @b.

b. Bit phOPng trnh cLa phn jng @ill gi s| rng n din ra vVi hi`u sut cao.c. S| d]ng bng th kh| chun dOVi My) $Jc Mnh n_ng lOUng %ibbs cLa phn jng @ill

2>9 =) Jp sut o$y 1 mm@g) p@ 9. *Jc cht khJc c nXng M^ tiIu chun. Miu ki`n


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b.

"@@

. nh toJn

G

"hn jng lQt\ phJt khng t\ phJt

R


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Figure 1 from H& Ehr!antraut/ E& Ra$in3itch&Kin*tic+ 8 Hi'' r*actin& ,9rchi3*+ 8 .ich*!i+try and .iphy+ic+/ 01:4/ 3& 2;/ pp&


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Nhu c@u l4;ng tcLa phn jng &uang o$i ha kh| MOUc Mnh ngha lQ s trung bnh cLa cJcphoton Jnh sJng khng nht thit phi lQ s nguyIn0 cKn thit cho vi`c chuyRn m t electron tcht kh| Mn cht o$y ha. *Jc l]c lNp b phn lqp M MOUc chiu $N trong thi gian 2 gi bim^t Jnh sJng MPn sZc bOVc sng 6?2 nm0 vVi n_ng lOUng 7)578 m;Cs) vQ tng lOUng o$y MOUchnh thQnh lQ :?)6 mm8trong cng Miu ki`n nhO trong cu :0.

5. nh nhu cKu lOUng t| cho phn jng @ill.nh toJn

,hu cKu lOUng t|


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-ro0lem %1 -h=n >ng Meere*n&chm*.t-onn.orGerley 6+ 7o*nts8

Guestion 1 2 8 : otala b

Harks ? 8 9.5 6 9 82.5

Heerwein-Schmidt-"onndorf-Berley HS"B0 reaction is a useful tool for reduction ofcarbonyl compounds to alcohols. he reaction is the reduction of carbonyl compounds by lowmolecular weight alcohols in the presence of alko$ides of aluminium or other metals

!@

D1 D2

!!@!

D1 D2 3l.!i"r08

10he mechanism of the reaction includes coordination of carbonyl compound by

aluminium alko$ide) hydride transfer in the inner sphere of the comple$ and subse&uenttransalko$ylation. (t can be schematically represented as follows transalko$ylation is shownas a one-step process for brevity0

3l

!

! !

!

D1 D2

!

D1 D2

3l

!

! !

@ !

D1 D2

3l

!

!

@

!i"r!@

3l

!

! !

!@

D1 D2

!

20


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3nswer!*8@9!0 !*6@17!0


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Rat*6'i!iting +t*p i+ th* hydrid* tran+8*r

erivation

r

3nswer


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!@

!@

!*@8

!*@8

!*@8

!@

@!

*@8!

!@

!@

!@

!@

:. Enanti!*ric *)c*++) **) is used to characteri#e the enantiomeric purity of the substance.his &uantity e&uals ratio of the difference of concentrations of enantiomersRand Sto theirsum

R S**

R S

=

+

+nantiomeric e$cess of the pureRisomer is unity) **of the racemic mi$ture is #ero.

When using the enantiomerically pure (,!E03l!i"r0 as a catalyst for reduction of -


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**


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-ro0lem 1 Mt thK ngh*m c Pn g*=n 6Q 7o*nts8

Guestion 1 2 8 otal

Harks 5 12 ? 2:

*ompound Awhich contains metal Xis a colorless crystalline solid and highly soluble inwater. (t is used as a reagent in analysis and gives in alkali media a binary compound Bcontaining 6.> mass0 of o$ygen. 'nder heating Adecomposes with a mass loss of 86.5.

1. etermine the metal Xand compounds A) B.

Your work

X A B


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C

Deaction e&uations

8. he compound Cbeing stored under the mother li&uor containing an e$cess of A0 itscolor changes to yellow due to the transformation into ). (f barium ions are added to thesuspension of Cin the mother li&uor) a mi$ture of )and of a white precipitate forms. "ropose


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-ro0lem 1 NhSng 45c tKnh Pn g*=n tKnh chUt cVa gra7hene 6? 7o*nts8

Guestion 1 2 8 otala b

Harks 2 2.5 : 5.5 1:%raphene is a two-dimensional) one atom thick carbon material Fig.1 a0. Hany layers ofgraphene stack together to form graphite Fig. 1b0.


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*alculations

S m2Cg

he single layer of nitrogen molecules adsorbed on the outer surface of graphite is shown inFig. 2. 3ssume that the same arrangement of nitrogen molecules is formed on a graphenesurface.


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Eet us consider adsorption as a common chemical e&uilibrium

gas ads3 3 ) 10

3gasare molecules 3 in the gaseous state) 3adsare the same molecules on the surface0with the e&uilibrium constantK

ads

gas

2

3

3

molCm 0bar0

nBp

=

such assumption holds if a small number of molecules is adsorbed on the surface0

3dsorption properties of graphene can be estimated from the data for adsorption on a regularthree-dimensional graphite. he enthalpy of adsorption Hoof reaction 100 of any molecule 3

on graphene is on average by 17 less negative compared to that on graphite. !n graphite) theadsorbed molecule is bound more strongly due to the interaction with the lower graphenelayers in the lattice Fig. 1b0 and hence the enthalpy of adsorption is more negative. hestandard entropies of adsorption on graphene and graphite are assumed to be the same.

2. @ow many moles) n) of **l:are adsorbed on 1 g of graphene at p**l:0 17:bar if2.717? mol of **l:are adsorbed on 1 m2of graphite atp**l:0 6.6175bar~ 3ssume that

graphene is placed onto the surface of a solid support and the interaction of **l :with thesupport does not change the enthalpy of adsorption of **l:on graphene. he temperature inboth cases is 2>8 =. Hoof adsorption of **l:on graphite is 85.1 k;Cmol.

*alculations


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2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0 4.2 4.4

-15

-14

-13

-12

-11

-10

-9

-8

-7

lnK

ln M

(a)

-32

-28

-24

-20

-16

-12

-8

0,k

Jmol-1

(b)


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*ontent of 2@6 mol.


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-ro0lem Q1 Cyclo7ro7ane1 ThWt Pn g*=n1 ThWt l m3tY 6+ 7o*nts8

Guestion 1 2 8 otalHarks 9 22 ?7 177

*yclopropanes bearing donor and acceptor substituents at the neighboring *-atoms) for e$ample) A)

demonstrate high reactivity behaving similar to 1)8-#witterion B.

hus) A$ :-!He0 undergoes the three-membered ring opening in the Eewis acid-cataly#ed

reaction with 1)8-dimetho$yben#ene as a nucleophile giving the product C.

1. Write down structural formula of C.

Structural formula of CZ


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-ro0lem ?1 &\ Pa .ng cVa 7ermanganat h;7 th>c 6+ 7o*nts8

Guest. 1 2 8 : 5 otala c d a b

Harks 2 2 : 2 2 6 ? ? 2 8:

he amount of many reducing agents can be determined by permanganatometric titration inalkaline medium allowing permanganate ion reduction to manganate.1. Write down the ionic e&uation of the reaction for formate titration with

permanganate in an a&ueous solution containing 7.5 H ,a!@.

itration with permanganate in alkaline medium is often supplemented by addition of a bariumsalt) which leads to precipitation of manganate as aHn!:.2. Which side redo$ processes involving manganate is suppressed by the barium salt~Write down an e$ample of e&uation of the corresponding reaction.

17.77 mE VHn0 of 7.7:77 Hn0 =Hn!:solution was placed in each of flasks ]) ^) and _


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b0 %ive the formula for the comple$ formed when 3gions were initially added to the cyanidesolution until the precipitate was formed0.

c0 %ive the formula of the precipitate formed.

d0 *alculate the mass of crotonic acid in mg0 if 5.:7 mE V3g0 of the silver salt solution wasconsumed for the titration to the endpoint.


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5. 3 sample containing tin((0 was added to flask _) and the medium was adusted to weakalkaline. in((0 was &uantitatively o$idi#ed to Sn!@062) whereas a precipitate formed as aresult of permanganate reduction. he precipitate was isolated) washed off) dried at 257)weighed the mass of the water-free precipitate !prec0) representing a binary compound Hn$!y)was of 29.6 mg0) and dissolved in @2S!:in the presence of an e$cess of potassium iodide. heevolved iodine was titrated with 7.1777 thiosulfate solution. 2.57 mE VS20 of the latter wasconsumed to attain the endpoint.

a0 etermine $ and y. Write down the reaction of precipitation.


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Deaction

b0 *alculate the mass of tin in the sample in mg0.


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-ro0lem +1 Cuc s`ng Pc Po cVa * bhun c: 6+ 7o*nts8

Guestion 1 2 8 : 5 6 ? 9 > otala b

Harks 2 ? 8 9 : : 5 : 8 5 :5

3rchaea or archaebacteria0 are single-celled microorganisms significantly differing frombacteria and eukaryotes at the molecular level.

+n#ymatic reaction of methylamine with water is the maor energy source for some archaea. (na particular e$periment) an archaea strain was cultivated at p@ ? under anaerobic o$ygen free0conditions with the nutrient medium containing 18@8,@2as the only energy source. 3fter acertain incubation period) the gas over the archaea culture was sampled and analy#ed. (t wasfound that the gas contains two substances ] and B in the molar ratio of 1.778.77correspondingly. he sample density rel. @2is of 12.7.

1. *alculate the volume fractions in 0 of ]and Bin the mi$ture.

2. etermine ]and B if there is no , atoms in gas collected.Your work


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3mino acid-lysine see the structure in scheme below0 was identified as the Xprecursor inarchaea. 3ll * and , atoms found in Xoriginate from two starting lysine molecules. ifferentisotope-labeled -lysines were introduced into a model system to clarify the biosynthetic

pathways of X. he results are summari#ed in the table.

(sotope composition of-lysine Holecular mass rounded to integer0 of the Xresidue D*@,@20*!) bound to tD,3)gCmol

,ormal 2893ll carbons 18) all nitrogens 15, 258-3mino group with 15, 28>

:. etermine the molecular formula of X.*alculations


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*alculations

* +

!$idative deaminationecarbo$ylation(ntermolecular deamination@ydro$ylation"eptide bond hydrolysis.

dcontains the fragment

(R,Me,H) (H,Me,R)


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?. raw structural formulae of C and Xwith stereochemical details. here are no stereocenters affected on the way from Cto X. Hark every stereocenter of Xwith eitherRor S.C X

!nly one codon is responsible for incorporation of Xresidues into proteins in archaea. henitrogen bases forming this codon contain two e$ocyclic amino groups and three e$ocyclic

o$ygen atoms in total.

9. Fill in the hereunder table to determine the nucleotide composition of the codon encodingX. T*cb only one 0o *n each l*ne.Your work


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,umber of amino acids

>b. Write down the amino acid se&uence translated from this fragment. ,ote that more thanone Xresidue is found in the fragment.Fill in the bo$es with the amino acid abbreviations from ,- to *-terminus0.

,ote that the number of bo$es is e$cessive. (f there is more than one possibility) write allseparated by C. (f the translation is stopped in a particular position) write S!" and leaveall the bo$es to the right empty.Your work


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6a8 RNA Co.ons fr the Tenty Am*no Ac*.s Am*no ac*.a00re*at*onsZ

second base

C A ( 3la 3lanine

"he Ser yr *ys

hird

base

3rg 3rginine

"he Ser yr *ys C 3sn 3sparagineEeu Ser S!" S!" A 3sp 3spartic acidEeu Ser S!" rp ( *ys *ysteine

C

Eeu "ro @is 3rg %lu %lutamic acidEeu "ro @is 3rg C %ln %lutamine

Eeu "ro %ln 3rg A %ly %lycineEeu "ro %ln 3rg ( @is @istidine

A(le hr 3sn Ser (le (soleucine(le hr 3sn Ser C Eeu Eeucine(le hr Eys 3rg A Eys Eysine

Hetstart0 hr Eys 3rg ( Het Hethionine

(

Bal 3la 3sp %ly "he "henylalanine

Bal 3la 3sp %ly C "ro "rolineBal 3la %lu %ly A Ser SerineBal 3la %lu %ly ( hr hreonine

rp ryptophan

yr yrosine

Bal Baline


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IChO-2013 Theoretical Official Viet Nam Version

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