Running iihead: iCHEMISTRY iTEST iASSIGNMENT
Chemistry iTest iAssignment i
Student’s iName
Institution iAffiliation i
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CHEMISTRY iTEST iASSIGNMENT i
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Section i1 i– iNumerical
1. We ihave iabout i10g iof iIron(II) iammonium isulphate icrystals. iWe imix ithese iand imake ia
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250cm3 iacidified isolution iof ithis. iApproximately i21.25cm3 iof ipotassium
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dichromate(VI) i(0.02 imol idm-3) iis ineeded ifor ioxidation iof i25cm3 iof ithe isolution imade.
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Given ithe iformula iof icrystal ias i
The ivalue iof ia+b+c+x iis? i
The igeneral iformula iof iIron(II) iammonium isulphate icrystals iis iFeSO4. i(NH4)2S04.
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xH2O
This imeans ithat ia iis i1, ib iis i2, ic iis i1 iand ix iis iwater iof icrystallisation.
Therefore, iwe iare ilooking ifor iwater iof icrystallisation:
Moles iof idichromate iions, iCr2O7^2– i i
Moles i= imolarity ix ivolume i/ i1000
= i0.0200 ix i21.25 i/ i1000 i= i0.000425 imol
Moles iof iIron(II) iammonium isulphate isalt;
Moles iof iiron isalt i= imol iFe2+ ititrated i
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= i6 ix iCr2O72– i= i6 ix i0.000425 i= i0.00255 imol
This imeans ithat i1/10 iof iFe2+ isalt iis iused iin ititration i(25/250cm3)
Therefore i1 ig iof iFeSO4. i(NH4)2S04. ixH2O iis iequal ito i0.00255 imol.
We iget ithe iRMM iof ithe isalt ifrom ithe iformula;
RMM i= imass/moles
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iiiiiiiiiii
= i1 i/0.00255 i= i392.2
Therefore, ithe iformula imass ifor iFeSO4. i(NH4) i2S04.xH2O iis i392.2.
Now ithe iformula imass iof iFeSO4. i(NH4)2S04;
= i56+32+64+28+8+96 i= i284
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Getting ithe idifference, i392.2 i– i284 i= i108.2
RFM iof iH2O= i18
Meaning, i18X i= i108.2
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X i= i6.011 i
Therefore, ia+b+c+x i= i1+2+1+6
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= i9
2. We ihave ian iiodine isolution i(25cm3). iIt iis ititrated iwith isodium ithiosulfate i(0.1 imol idm-3).
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With ithis, iaround i17.6cm3 iof iiodine isolution ireacted. iThe iconcentration iof iiodine iis
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then ifound iout ito ibe ix imol idm-3 iand iy ig idm-3. i
Evaluate: i(y i– ix)? i
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The ireaction iinvolved iis iwritten ias iionic iequation ias ishown ibelow
I2(aq) i+ i2S2O32–(aq) i==> iS4O62–(aq) i+ i2I–(aq)
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Or ias ithe iwhole ichemical iequation ias;
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I2(aq) i+ i2Na2S2O3(aq) i==> iNa2S4O6(aq) i+ i2NaI(aq)
Moles iof isodium ithiosulfate;
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iiiiiiii
Moles i= i(molarity/1000) ix ivolume
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= i0.100 ix i17.6/1000 i= i0.00176 imol
Moles iof iiodine
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I2 i= i0.00176 i÷ i2 i= i0.00088 iin i25 icm3,
Molarity iin imol idm–3 i
M i= i(moles ix i1000)/volume
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= i0.00088 ix i1000 i÷ i25 i= i0.0352 imol idm–3 i
Molarity iin ig idm–3
Molecular imass iof iiodine imolecule, iI2 i= i2 ix i127 i= i254
Therefore, iconcentration i= imolarity ix iRMM
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= i0.0352 ix i254 i= i8.94 ig idm–3
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CHEMISTRY iTEST iASSIGNMENT i
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Section i2 i– iTheoretical
Addition iReactions iof iBenzene iCompounds
Table iof iContents i
Figure i1……………………………………………………………………………….5
Introduction…………………………………………………………………………...4
Addition iMechanism………………………………………………………………….4
Uses iof ithe iCompound………………………………………………………………..5
References…………………………………………………………………………….7
Introduction i
Benzene, iC6H6, iis ithe isimplest imember iof ia ilarge ifamily iof ihydrocarbons, icalled iaromatic
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hydrocarbons i(Alan R. Katritzky, 2010). iThese icompounds icontain iring istructures iand iexhibit
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bonding ithat imust ibe idescribed iusing ithe iresonance ihybrid iconcept iof ivalence ibond itheory ior ithe
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delocalization iconcept iof imolecular iorbital itheory. i
Addition iMechanism
When ia ibenzene iring ihas itwo isubstituent igroups, ieach iexerts ian iinfluence ion isubsequent
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substitution ireactions. iThe iactivation ior ideactivation iof ithe iring ican ibe ipredicted imore ior iless iby
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the isum iof ithe iindividual ieffects iof ithese isubstituents. iThe isite iat iwhich ia inew isubstituent iis
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introduced idepends ion ithe iorientation iof ithe iexisting igroups iand itheir iindividual idirecting ieffects
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(Mndzhoian, 2013). iThus, ithe igroups imay ibe ioriented iin isuch ia imanner ithat itheir idirecting
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influences iact iin iconcert, ireinforcing ithe ioutcome; ior iare iopposed. i iIn iour icase, ithe ibenzene
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compound ireacts iwith itetra imethyl iamine igroup iin iaddition ireaction iin ithe ipresence iof isodium
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methoxide iand imethanol ito iform ipyridine i(John A. Joule, 2010).
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Figure i1: iThe iaddition iprocess
Although iit idoes iso iless ireadily ithan isimple ialkenes ior idienes, ibenzene iadds ihydrogen iat ihigh
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pressure iin ithe ipresence iof isodium imethoxide iand imethanol icatalysts. iThe iproduct iis icyclohexane
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and ithe iheat iof ireaction iprovides ievidence iof ibenzene's ithermodynamic istability. iSubstituted
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benzene irings imay ialso ibe ireduced iin ithis ifashion, iand ihydroxy-substituted icompounds, isuch ias
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phenol, icatechol iand iresorcinol, igive icarbonyl iproducts iresulting ifrom ithe ifast iketonization iof
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intermediate ienols i(Tadeusz Marek Krygowski, 2009). iNickel icatalysts iare ioften iused ifor ithis
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purpose.
Benzene iis imore isusceptible ito iradical iaddition ireactions ithan ito ielectrophilic iaddition. iWe ihave
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already inoted ithat ibenzene idoes inot ireact iwith ichlorine ior ibromine iin ithe iabsence iof ia icatalyst
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and iheat. iIn istrong isunlight ior iwith iradical iinitiators ibenzene iadds ithese ihalogens ito igive
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hexahalocyclohexanes. iIt iis iworth inoting ithat ithese isame iconditions ieffect iradical isubstitution iof
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cyclohexane, ithe ikey ifactors iin ithis ichange iof ibehaviour iare ithe ipi-bonds iarray iin ibenzene, iwhich
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permit iaddition, iand ithe iweaker iC-H ibonds iin icyclohexane i(Frank De Proft, 2014). i
Uses iof ithe iCompound i
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Heterocyclic icompounds iare iof ivery imuch iinterest iin iour idaily ilife. iThey ihave ihigh isignificance
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in iour iliving isystem. iHeterocyclic icompounds ihave ia iwide irange iof iapplications iin
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agrochemicals, ipharmaceuticals, iveterinary iproducts ietc. iThey iare ialso iused ias istarting imaterial
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in ithe isynthesis iof iorganic icompounds. iThese iare ialso iused iin isanitizers, idevelopers, ianti-
ordinates, icorrosion iinhibitors ietc. iHeterocyclic icompounds iare ithe icyclic icompounds iwhich
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contain ione ior imore idifferent iatoms iother ithan icarbon iin ia iring istructure. iThese icompounds imay
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be iaromatic ior ianti-aromatic. iHeterocyclic icompounds iwidely ifound iin inature, ie.g. ipyramiding
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and ipurine iare ithe iparts iof iDNA, ivitamins iand ienzymes. iHeterocyclic icompounds iare ivery
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important ifor ihuman isurvival itoo. iThey iare iimportant iinformation icarrier. iThese iare iused iin
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neurotransmitter iand ipyrimidines; inucleoside iis ia ipart iof igenetic imaterial ithat itransfers
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information ifrom ione igeneration ito iother.
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CHEMISTRY iTEST iASSIGNMENT i
References
Alan iR. iKatritzky, iC. iA. iR. iJ. iA. iJ. iV. iV. iZ., i2010. iHandbook iof iHeterocyclic iChemistry. i3
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ed. iLondon: iElsevier.
Frank iDe iProft, iP. iG., i2014. iStructure, iBonding iand iReactivity iof iHeterocyclic iCompounds.
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2 ied. iNew iYork: iSpringer.
John iA. iJoule, iK. iM., i2010. iHeterocyclic iChemistry. i5 ied. iLondon: iJohn iWiley i& iSons.
Mndzhoian, iA. iL., i2013. iSynthesis iof iHeterocyclic iCompounds. i1 ied. iNew iYork: iSpringer
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Science i& iBusiness iMedia.
Tadeusz iMarek iKrygowski, iM. iK. iC., i2009. iAromaticity iin iHeterocyclic iCompounds. i2 ied.
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London: iSpringer iScience i& iBusiness iMedia.
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