PORTAGE LEARNING ORGANIC CHEMISTRY CHEM 219
FINAL EXAM ALL VERSIONS LATEST VERIFIED;;
SIMPLIFIED AND
SUMMARIZED
Stereochemistry c- cANSWER cthe cstudy cof cthe cthree-dimensional cstructure cof cmolecules
Stereoisomers c- cANSWER cCompounds cwith cthe csame cstructural cformula cand cconnectivity
cbut cwith ca cdifferent c3D carrangement cof cthe catoms cin cspace.
Enantiomers c- cANSWER cStereoisomers cthat cthat care cnon-superimposable cmirror cimages.
cEnantiomers chave cthe csame cconnectivity cbut cdifferent corientations c(twist) cof cthe cfour catoms
,cor cgroups cin c3D cspace.
The ctwo cdifferent cforms cof cthe cchiral cmolecule c(the c"left-handed" cform cor ca c"right-
handed" cforms)
How cdo cthe cdifferences ccaused cby csteroisomers cdiffer cthan cthe cdifferences ccaused cby
cconstitutional cisomers. c- cANSWER cWhile cthe cstructural cdifferences cbetween cstereoisomers
care cmore csubtle cthan cthose cbetween cconstitutional cisomers, cstereoisomerism cis coften
cresponsible cfor csignificant cdifferences cin cthe cchemical cand cphysical cproperties cof corganic
ccompounds, cincluding cthe cbiochemical cbehavior cof cmany ccompounds csuch cas cdrug
cmolecules, camino cacids, ccarbohydrates, cand cnucleic cacids. cSeveral cof cthe chuman csenses,
cespecially csmell, care cgreatly caffected cby cstereoisomerism cin corganic ccompounds.
cis-stereoisomers c- cANSWER chave cthe csubstituents con cthe csame cside/face cof cthe cring cor
cdouble cbond
trans-stereoisomers c- cANSWER chave cthe csubstituents con copposite csides/faces cof cthe cring
cor cdouble cbond
,Chirality c- cANSWER cthe cconcept cof c"handedness" cin can cobject.
Consider cthe cdifference cbetween ca cpair cof csocks cand ca cpair cof cgloves. cA csock ccan cbe cworn
(interchangeably) con ceither cthe cleft cor cright cfoot, cbut cthe csame cis cnot ctrue cfor cthe
cgloves. cA cleft- chanded cglove ccannot cbe cworn con cthe cright chand cand cvice-versa. cThe
cgloves cpossess cthe cproperty cof c"handedness" c(chirality)
Observation cwill creveal cthat cchiral cobjects care ctypically cnot csymmetrical c(asymmetric),
cwhile cachiral cobjects ctypically cexhibit cmultiple cplanes cof csymmetry cwithin cthe cobject
citself.
chiral c- cANSWER ca cmolecule cthat cis cnot csuperimposable con cits cmirror cimage c(possesses
cthe cproperty cof chandedness)
achiral c- cANSWER cA cmolecule cthat cis csuperimposable con cits cmirror cimage c(does cnot cpossess
cthe cproperty cof chandedness)
What ctest ccan cbe capplied cto cdetermine cif can cobject cis cchiral cor cachiral? c- cANSWER cA csimple
ctest cinvolves ccomparing cthe cobject cand cits cmirror cimage cfor csuperimposability.
Superimposability c- cANSWER cThe cability cto calign c(overlap) ctwo cobjects cso cthat cevery
cunique cpart cof ceach cis cin cdirect calignment cwith cthe csame cunique cpart con cthe cother.
What cdoes cit cmean cwhen ca cmolecule cis ca cchiral cmolecule? c- cANSWER cAn corganic
ccompound cthat ccan cexist cas ctwo cdifferent cforms c("left-handed" cform cor ca c"right-handed"
cform)
Is clactic cacid cstructure cchiral cor cachiral? c- cANSWER cAttempting cto csuperimpose clactic cacid
cand cits cmirror cimage creveals cthat cthe ctwo cforms ccannot cbe csuperimposed, cand cthus, cthe
cmolecule cis
chiral, cand cit cexists cas ctwo cseparate cforms cknown cas cenantiomers c(Figure c3.4). cNo
cmatter chow cone cof cthe cstructures cis crotated, cit cis cimpossible cto cget call cof cthe
catoms/groups cin cone cto calign cwith cthe csame catoms/groups cin cthe cmirror cimage
cstructure.
, Is cthe cmolecule c2-chloropropane cchiral cor cachiral? c- cANSWER cWhen cthe c3D cstructure cof
cthis cmolecule cis cdrawn, ca ctetrahedral cgeometry cis cobserved caround cthe ccentral ccarbon,
csimilar cto cthat cof clactic cacid. cAt cfirst cglance, cit cmay cnot cbe cclear cthat cthe cmolecule cis
cachiral. cIt cis conly cthrough cthe capplication cof cthe csuperimposability ctest cthat cthe
cmolecule creveals cits cachiral cnature.
The cabsence cof ca cstereocenter cis cthe creason cwhy cmolecules clike c2-chloropropane care
cachiral. cAn canalysis cof cthe c3D cstructure cof c2-chloropropane creveals ca ctetrahedral
cgeometry caround cthe ccentral ccarbon cbut conly cthree cdifferent ctypes cof catoms cor cgroups
cattached c(there cwere c4 cbonds cto cthe ccarbon cbut c2 cof cthe cgroups cwere cidentical). cThe
csymmetrical cnature cof cthe c2-
chloropropane cmolecule ccomes cfrom chaving ctwo cof cthe csame cgroup con cthe ccentral ccarbon c-
cthis callows cthe cstructure cto cbe csuperimposed con cits cown cmirror cimage, cand cthus, cmakes cthe
cmolecule cachiral.
What cis cthe cmost ccommon ccause cof cchirality cin can corganic cmolecule? c- cANSWER cThe
cpresence cof ca ctetrahedral cstereocenter.
Identifying ca cstereocenter cin can corganic cmolecule cis ca cway cto cquickly cdetermine cif can
corganic cmolecule cmay cpossess cthe cproperty cof cchirality.
stereocenter c- cANSWER cA ccarbon catom cwith ctetrahedral cgeometry cthat cis cbonded cto cfour
cDIFFERENT catoms cor cgroups c(4 csingle cbonds cconnected cto cfour cdifferent catoms cor
cgroups).
This ctype cof ccarbon cis cknown cas ca cstereocenter, ca cstereogenic ccenter, cor ca cchiral ccenter.
A cchiral cmolecule cwill calmost calways cpossess cone c(or cmore) cstereocenters. cIn ccontrast, cmost
cmolecules cwithout ca cstereocenter care cnot cchiral.
Stereocenter cvs cChirality c- cANSWER cThe cstereocenter cis cthe ccause cof cthe cchirality, cwhile
cchirality cis ca cproperty cof cthe cmolecule cas ca cwhole.
FINAL EXAM ALL VERSIONS LATEST VERIFIED;;
SIMPLIFIED AND
SUMMARIZED
Stereochemistry c- cANSWER cthe cstudy cof cthe cthree-dimensional cstructure cof cmolecules
Stereoisomers c- cANSWER cCompounds cwith cthe csame cstructural cformula cand cconnectivity
cbut cwith ca cdifferent c3D carrangement cof cthe catoms cin cspace.
Enantiomers c- cANSWER cStereoisomers cthat cthat care cnon-superimposable cmirror cimages.
cEnantiomers chave cthe csame cconnectivity cbut cdifferent corientations c(twist) cof cthe cfour catoms
,cor cgroups cin c3D cspace.
The ctwo cdifferent cforms cof cthe cchiral cmolecule c(the c"left-handed" cform cor ca c"right-
handed" cforms)
How cdo cthe cdifferences ccaused cby csteroisomers cdiffer cthan cthe cdifferences ccaused cby
cconstitutional cisomers. c- cANSWER cWhile cthe cstructural cdifferences cbetween cstereoisomers
care cmore csubtle cthan cthose cbetween cconstitutional cisomers, cstereoisomerism cis coften
cresponsible cfor csignificant cdifferences cin cthe cchemical cand cphysical cproperties cof corganic
ccompounds, cincluding cthe cbiochemical cbehavior cof cmany ccompounds csuch cas cdrug
cmolecules, camino cacids, ccarbohydrates, cand cnucleic cacids. cSeveral cof cthe chuman csenses,
cespecially csmell, care cgreatly caffected cby cstereoisomerism cin corganic ccompounds.
cis-stereoisomers c- cANSWER chave cthe csubstituents con cthe csame cside/face cof cthe cring cor
cdouble cbond
trans-stereoisomers c- cANSWER chave cthe csubstituents con copposite csides/faces cof cthe cring
cor cdouble cbond
,Chirality c- cANSWER cthe cconcept cof c"handedness" cin can cobject.
Consider cthe cdifference cbetween ca cpair cof csocks cand ca cpair cof cgloves. cA csock ccan cbe cworn
(interchangeably) con ceither cthe cleft cor cright cfoot, cbut cthe csame cis cnot ctrue cfor cthe
cgloves. cA cleft- chanded cglove ccannot cbe cworn con cthe cright chand cand cvice-versa. cThe
cgloves cpossess cthe cproperty cof c"handedness" c(chirality)
Observation cwill creveal cthat cchiral cobjects care ctypically cnot csymmetrical c(asymmetric),
cwhile cachiral cobjects ctypically cexhibit cmultiple cplanes cof csymmetry cwithin cthe cobject
citself.
chiral c- cANSWER ca cmolecule cthat cis cnot csuperimposable con cits cmirror cimage c(possesses
cthe cproperty cof chandedness)
achiral c- cANSWER cA cmolecule cthat cis csuperimposable con cits cmirror cimage c(does cnot cpossess
cthe cproperty cof chandedness)
What ctest ccan cbe capplied cto cdetermine cif can cobject cis cchiral cor cachiral? c- cANSWER cA csimple
ctest cinvolves ccomparing cthe cobject cand cits cmirror cimage cfor csuperimposability.
Superimposability c- cANSWER cThe cability cto calign c(overlap) ctwo cobjects cso cthat cevery
cunique cpart cof ceach cis cin cdirect calignment cwith cthe csame cunique cpart con cthe cother.
What cdoes cit cmean cwhen ca cmolecule cis ca cchiral cmolecule? c- cANSWER cAn corganic
ccompound cthat ccan cexist cas ctwo cdifferent cforms c("left-handed" cform cor ca c"right-handed"
cform)
Is clactic cacid cstructure cchiral cor cachiral? c- cANSWER cAttempting cto csuperimpose clactic cacid
cand cits cmirror cimage creveals cthat cthe ctwo cforms ccannot cbe csuperimposed, cand cthus, cthe
cmolecule cis
chiral, cand cit cexists cas ctwo cseparate cforms cknown cas cenantiomers c(Figure c3.4). cNo
cmatter chow cone cof cthe cstructures cis crotated, cit cis cimpossible cto cget call cof cthe
catoms/groups cin cone cto calign cwith cthe csame catoms/groups cin cthe cmirror cimage
cstructure.
, Is cthe cmolecule c2-chloropropane cchiral cor cachiral? c- cANSWER cWhen cthe c3D cstructure cof
cthis cmolecule cis cdrawn, ca ctetrahedral cgeometry cis cobserved caround cthe ccentral ccarbon,
csimilar cto cthat cof clactic cacid. cAt cfirst cglance, cit cmay cnot cbe cclear cthat cthe cmolecule cis
cachiral. cIt cis conly cthrough cthe capplication cof cthe csuperimposability ctest cthat cthe
cmolecule creveals cits cachiral cnature.
The cabsence cof ca cstereocenter cis cthe creason cwhy cmolecules clike c2-chloropropane care
cachiral. cAn canalysis cof cthe c3D cstructure cof c2-chloropropane creveals ca ctetrahedral
cgeometry caround cthe ccentral ccarbon cbut conly cthree cdifferent ctypes cof catoms cor cgroups
cattached c(there cwere c4 cbonds cto cthe ccarbon cbut c2 cof cthe cgroups cwere cidentical). cThe
csymmetrical cnature cof cthe c2-
chloropropane cmolecule ccomes cfrom chaving ctwo cof cthe csame cgroup con cthe ccentral ccarbon c-
cthis callows cthe cstructure cto cbe csuperimposed con cits cown cmirror cimage, cand cthus, cmakes cthe
cmolecule cachiral.
What cis cthe cmost ccommon ccause cof cchirality cin can corganic cmolecule? c- cANSWER cThe
cpresence cof ca ctetrahedral cstereocenter.
Identifying ca cstereocenter cin can corganic cmolecule cis ca cway cto cquickly cdetermine cif can
corganic cmolecule cmay cpossess cthe cproperty cof cchirality.
stereocenter c- cANSWER cA ccarbon catom cwith ctetrahedral cgeometry cthat cis cbonded cto cfour
cDIFFERENT catoms cor cgroups c(4 csingle cbonds cconnected cto cfour cdifferent catoms cor
cgroups).
This ctype cof ccarbon cis cknown cas ca cstereocenter, ca cstereogenic ccenter, cor ca cchiral ccenter.
A cchiral cmolecule cwill calmost calways cpossess cone c(or cmore) cstereocenters. cIn ccontrast, cmost
cmolecules cwithout ca cstereocenter care cnot cchiral.
Stereocenter cvs cChirality c- cANSWER cThe cstereocenter cis cthe ccause cof cthe cchirality, cwhile
cchirality cis ca cproperty cof cthe cmolecule cas ca cwhole.
