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CHEMISTRY PAPER 3 EDEXCEL QUESTIONS WITH CORRECT ANSWERS.
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CHEMISTRY PAPER 3 EDEXCEL QUESTIONS WITH CORRECT ANSWERS.
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CHEMISTRY PAPER 3 EDEXCELQUESTIONS WITH CORRECT ANSWERS
State oowhat oois oomeant ooby ooa ooBrønsted-Lowry ooacid. oo- ooCorrect ooAnswer oo- ooA
ooproton oodoner
Write oothe ooexpression oothat oodefines oothe oopH ooof ooa oosolution. oo- ooCorrect
ooAnswer oo- oopH=-log[H+]
Calculate oothe ooconcentration ooof oohydrogen ooions, ooin oomol oodm-3, ooin ooa oosolution
oowith ooa oopH ooof oo2.76 oo- ooCorrect ooAnswer oo- oo[H+] oo= oo10 oo^-pH
=10^-2.76
= oo1.74 oox oo10^-3 oomol.dm^-3
Explain oowhy oothe oopH ooof ooa oo1 oo× oo10-8 oomol oodm-3 oosolution ooof oonitric ooacid,
ooHNO3 oo, oois oonot oo8. oo[Ionic ooproduct ooof oowater, ooKw oo= oo1.00 oo× oo10-14 oomol2
oodm-6] oo- ooCorrect ooAnswer oo- ooThe oowater oocontains oosome ooH+ ooions
Concentration ooof oohydrogen ooions oofrom oowater oois oonegligible/ oocannot oobe
ooignored
Aqueous oosodium oocarbonate ooand ooaqueous oosodium oosulfate ooare ooboth
oocolourless oosolutions.
(a) ooGive oothe ooreagent ooand oothe ooobservation ooto ooshow oothe oopresence ooof
oocarbonate ooions. oo- ooCorrect ooAnswer oo- ooaddition ooof oodilute oohydrochloric ooacid
ooand ooeffervescence/bubbling
Give oothe ooreagent ooand oothe ooobservation ooto ooshow oothe oopresence ooof oosulfate
ooions. oo- ooCorrect ooAnswer oo- ooAddition ooof oobarium oochloride oosolution oo(BaCl2)
White ooprecipitate ooforms
This ooquestion oois ooabout ooflame ootests oofor ooGroup oo1 ooand oo2 oometal ooions.
(a) oo(i) ooState oothe oocolour ooof oothe ooflame ooproduced ooby ooseparate oosamples ooof
oopotassium ooand
strontium ooions. oo- ooCorrect ooAnswer oo- ooPotassium ooions oo- ooLilac
Strontium ooions oo- ooCrimson oored
Give ooa ooreason oowhy oocarrying ooout ooa ooflame ootest ooon ooa oomixture ooof
oopotassium oochloride ooand oostrontium oochloride oodoes oonot ooclearly ooshow oothat
ootwo oodifferent oometal ooionsare oopresent. oo- ooCorrect ooAnswer oo- ooThe oocrimson
, oored oocolour oowill oohide oothe ooLilac oocolour oobecause ooit oois oodarker ooand ooit oowill
ootherefore oobe ooharder ooto oodistinguish oobetween oothe ootwo
In oothe oofirst oostage ooof oothe ooflame ootest, oothe oonichrome oowire oois oodipped oointo
ooconcentrated oohydrochloric ooacid ooand oothen ooheated ooin ooa ooBunsen ooflame.
In oothe oosecond oostage, oothis oonichrome oowire oois oodipped oointo oofresh oohydrochloric
ooacid ooand oothen oointo oothe oometal oosalt ooto oobe ootested oobefore oobeing ooreheated
ooin oothe ooBunsen ooflame.
(i) ooGive ootwo ooreasons oowhy oothe oowire oois oomade ooof oonichrome ooand oonot ooiron.
oo- ooCorrect ooAnswer oo- ooNichrome ooproduces oono oocolour ooand oois ooinert
Iron oocan ooproduce ooa oocolour ooand ooreact oowith oooxygen
Give ooa ooreason oowhy oothe oowire oois oodipped oointo ooacid ooand oothen ooheated ooin
oothe oofirst oostage. oo- ooCorrect ooAnswer oo- ooIt oois ooheated ooto ooremove oothe
ooresidue ooof oothe ooprevious oosample oobeing ootested
State oowhy oofresh ooconcentrated oohydrochloric ooacid oois ooused ooin oothe oosecond
oostage ooof oothe ooflame ootest. oo- ooCorrect ooAnswer oo- ooThe ooacid oocan oobecome
oocontaminated oowith ooresidue oofrom ooprevious ootests oo(which oocan ooproduce
ooincorrect ooresults)
State oowhy oohydrochloric ooacid oois ooused ooin oothe oosecond oostage ooof oothe ooflame
ootest. oo- ooCorrect ooAnswer oo- ooConcentrated oohydrochloric ooacid ooproduces oovolatile
oochlorides
Explain, oowith ooreference ooto ooelectron ootransitions, oothe ooformation ooof oothe oocolour
ooin ooa
flame ootest. oo- ooCorrect ooAnswer oo- ooElectrons ooare ooexcited ooand ooare oopromoted
ooto oohigher ooenergy oolevels oo
Electrons oofall oofrom oothe ooexcited oostate ooto oolower ooenergy oolevels
Electrons oorelease ooenergy/photons ooas oovisible oolight
Write oothe ooformula ooof oopotassium oochlorate(V). oo- ooCorrect ooAnswer oo- ooKClo3
Write oothe ooequation oofor oothe oofirst ooelectron ooaffinity ooof oochlorine. ooInclude oostate
oosymbols. oo- ooCorrect ooAnswer oo- ooCl(g) oo+ ooe- oo-----> ooCl-(g)
The oostandard ooelectrode oopotential oofor oothe oochlorine oo/ oochloride ooion oohalf-cell
oois oo
1⁄2Cl oo(aq) oo+ ooe− oo⇌ ooCl−(aq) ooEO oo= oo+1.36V oo
(i) ooIdentify ooan oooxidising ooagent oofrom oothe ooData ooBooklet oothat oowill ooconvert
oochloride ooions oointo oochlorine oounder oostandard ooconditions. oo- ooCorrect ooAnswer oo-
ooacidified oopotassium oomanganate
Analysis ooshows oothat ooa oocompound oohas oothe oomolecular ooformula ooC4H8O2. ooA
oostudent oosuggests oothat oothe oocompound oocould oobe ooeither ooA ooor ooB.
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