Version a Answers ochem Luk

8/13/2019 Version a Answers ochem Luk

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CHE276 Organic Chemistry laboratory I Quiz Fall 2013ast !ame"

First !ame"

#tu$ent I%"

1& ' sam(le )or thin layer chromatogra(hy containing t*o com(oun$s +say, t*o $ye

molecules- *as contaminate$ by a stu$ent *ith t*o other com(oun$s& .he ne/t

stu$ent came an$ run the .C o) the contaminate$ sam(le& oul$ the secon$stu$ent still be able to get the correct ) alues )or the original t*o com(oun$s

'& 4es

5& !OC& Cannot be $etermine$&

4E#& .he ) alue neer change *hen there is no coalent reactions&

2& sing a (olar solent, a stu$ent runs a .C )or t*o molecules on the same .C

(late, *hich molecule *ill hae a smaller ) alue

'& .he more (olar molecule&5& .he less (olar molecule&

C& Cannot be $etermine$ *ith the in)ormation gien&

.he more (olar molecule al*ays has a smaller ) alue than the non(olar molecule,

regar$less o) the (olarity o) eluent solent& .his is because (olar molecules interact

*ith silica gel stronger than non(olar molecules $o&

3& sing a non(olar solent, a stu$ent runs a .C )or t*o molecules on the same.C (late, *hich molecule *ill hae a smaller ) alue'& .he more (olar molecule&

5& .he less (olar molecule&


.he more (olar molecule al*ays has a smaller ) alue than the non(olar molecule,

regar$less o) the (olarity o) eluent solent&

& Consi$ering tem(erature an$ solubility, *hat *oul$ be the criteria )or a goo$

solent )or recrystallization o) a targete$ molecule

'& 8olar solent is goo$, non9(olar solent is not e))ectie&5& It $e(en$s on the )unctional grou( o) the targete$ molecule&

C& It $issoles the targete$ molecule at high tem(erature, but not at lo* tem(erature&

%& It $issoles the targete$ molecule slo*ly&

'ns*er is C

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:& .he .C o) a com(oun$ is run t*ice on t*o $i))erent .C (lates, once in a (olarsolent, the other in a non9(olar solent& In *hich eluent solent *ill the s(ot hae a

high ) alue

'& !on(olar solent&5& 8olar solent&


.he (olar solent interacts *ith the com(oun$ on .C stronger than the non(olar

solent $oes& #o, the com(oun$ *ill be moe$ u( more by (olar solent than by

non(olar solents& .hus, the (olar solent *ill cause the s(ot to hae a higher )

alue&

6& hat ;in$ o) a


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?& hat ;in$ o) a


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'& 'n aci$ic solution&

5& ' basic solution&C& ' solution *ith high concentration o) salts&

%& .here is no goo$ *ay to se(arate the t*o molecules base$ on e/traction metho$&

!either molecule is aci$ic nor basic, so there is no goo$ *ay to se(arate by

e/traction&

11& hat metho$+s- *oul$ you (ro(ose to attem(t to se(arate the )ollo*ing t*o

molecules

'& E/traction an$ ecrystallization

5& E/traction an$ Column chromatogra(hyC& ecrystallization an$ Column chromatogra(hy

%& Only recrystallization

E& Only Column chromatogra(hy

column )or sure, recrystallization nee$ s;ill an$ e/(erience, but most li;ely *ill

*or;

12& hen a mi/ture o) )our com(oun$s is elute$ through a column, Com(oun$ A

comes out the )irst, then Com(oun$ 4, B, an$ & hat is ran;ing o) the )our

com(oun$s )rom high to lo* (olarity'& A,4,B,

5& , B, 4, A

C& ,A,4,B

%& Cannot be $etermine$ base$ on the in)ormation&

olecule comes out later, moe slo*er on column, has the higher (olarity than

molecule comes out )irst&

13 hen a mi/ture o) t*o com(oun$s are elute$ through a column to be se(arate$,

but the com(oun$s neer come out a)ter a long time& hat may li;ely be thesolution to this (roblem

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'& >ust ;ee( running the column *ith more eluent solent&5& un the column all oer again using ne* sam(le, an$ *ith more (olar eluent

solent&

C& un the column all oer again using ne* sam(le, an$ *ith less (olar eluentsolent&

%& Cannot be $etermine$ base$ on the in)ormation&

>ust li;e .C, *hen the solent is not (olar enough, the molecules on the column or

tlc $o not enough&

1& hen a mi/ture o) t*o com(oun$s is elute$ through a column to be se(arate$,both com(oun$s come out rather


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C& $ecrease

C

1@& hich o) the )ollo*ing t*o mi/tures can be more easily se(arate$ by$istillation . is the boiling tem(erature o) the sam(le&

'

'& .he one on the le)t&

5& .he one on the right&

C& Cannot be $etermine$ by the in)ormation gien&

C

20& hat is the name o) the ty(ical sel)9assembly )orme$ by CH3+CH2-11O#O39!a=in

an a


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%& #ur)actantE& i(i$

C'lso, esicle are ma$e o) li(i$ bilayers&

22& hich o) the )ollo*ing t*o molecules is less (olar

'& .he one on the le)t&5& .he one on the right&

C& Cannot be $etermine$ base$ on the in)ormation gien&

Hy$rogen bon$ $onor has higher (olarity than hy$rogen bon$ acce(tor&Hy$rogen bon$ $onor is al*ays also hy$rogen bon$ acce(tor&

Hy$rogen bon$ $onor causes the molecule )orm hy$rogen bon$ing *ith itsel)&Hy$rogen bon$ acce(tor only )orm hy$rogen bon$ing *ith other molecules than has

hy$rogen bon$ $onor&

23& uning 1,29(entane$iol an$ 19(entanol on the same .C (late, *hich *ill hae a

higher ) alue on the .C (late

'& 19(entanol5& 1,29(entane$iol

C& cannot be $etermine$

higher ) alue im(lies lo* (olarity, less hy$rogen bon$ing $ecreases (olarity&

Consi$er the )ollo*ing 3 $rug molecules&

2& hich molecule is an organic base

'& molecule on the le)t&5& molecule in the mi$$le

C& molecule on the right

%& all o) them

E& molecules in the mi$$le an$ on the right

Organic base has nitrogen atom that has lone (air o) electron that are not conGugate$&

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!H2, 2!H are bases&

.he )ollo*ing molecules are note bases& the electron on the nitrogen is not aailable)or (rotons because o) the strong conGugation *ith the carbonyl grou(&

2:& hich molecule is a conGugate base o) an organic aci$'& molecule on the le)t&

5& molecule in the mi$$leC& molecule on the right%& molecules on the le)t an$ in the mi$$le

E& molecules in the mi$$le an$ on the right

COO9

26& hich molecule is neither an organic aci$ nor organic base'& molecule on the le)t&

5& molecule in the mi$$le

C& molecule on the right

%& molecules on the le)t an$ in the mi$$leE& molecules in the mi$$le an$ on the right

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