OCR A- Level Chemistry Paper 1

OCR A-Level Chemistry Paper 1

DefinekkTransitionkkelementkkcorrectkkanswersAkkd-
blockkkelementkkthatkkcankkformkkatkkleastkkonekkstablekkionkkwithkkankkincompletekkdkksub-shell

Whykkaren'tkkscandiumkkandkkZinckktransitionkkelements?correctkkanswersCannotkkformkkstablekkionskk
withkkankkincompletekkd-subkkshell.kkSckk3+kkhaskkankkemptykkd-
subkkshellkkandkkZnkk2+kkhaskkakkfullkkdkksubkkshell.

NamekkthekkoxidationkkstateskkandkkcolouredkkionskkforkkManganesecorrectkkanswersMnO4kk-kk(purple)
MnO4kk2-kk(green)
Mnkk2+kk(palekkpink)

NamekkthekkoxidationkkstatekkandkkcolouredkkionskkforkkTitaniumcorrectkkanswersTikk3+kk(purple)
Tikk2+kk(violet)

NamekkthekkoxidationkkstatekkandkkcolouredkkionskkforkkVanadiumcorrectkkanswersVO2kk+kk(yellow)
VOkk2+kk(blue)
Vkk3+kk(green)
Vkk2+kk(violet)

NamekkthekkoxidationkkstatekkandkkcolouredkkionskkforkkChromiumcorrectkkanswersCr2O7kk2-kk(orange)
Crkk3+kk(violet)

NamekkthekkoxidationkkstatekkandkkcolouredkkionskkforkkIroncorrectkkanswersFekk3+kk(yellow)
Fekk2+kk(palekkgreen)

NamekkthekkoxidationkkstatekkandkkcolouredkkionskkforkkCobaltcorrectkkanswersCokk2+kk(pink)

NamekkthekkoxidationkkstatekkandkkcolouredkkionskkforkkNickelcorrectkkanswersNikk2+kk(green)

NamekkthekkoxidationkkstatekkandkkcolouredkkionskkforkkCoppercorrectkkanswersCukk2+kk(palekkblue)

Whykkarekktransitionkkelementskkgoodkkcatalysts?kk(+kkonekkdownside)correctkkanswersCankkeasilykkcha
ngekkoxidationkkstateskkbykkgainingkkorkkloosingkkelectronskkwithinkkthekkd-
orbital.kkTransitionkkmetalskkarekkalsokkgoodkkatkkadsorbingkksubstanceskkontokktheirkksurfaceskklowerkkth
ankkthekkactivationkkenergykkofkkthekkreactions.kkGoodkkforkkindustrykkandkkenvironmentkkaskkreactionskkc
ankkhappenkkfasterkkatkklowerkktemperatureskkandkkpressure.
Poseskkhealthkkriskskkwithkkexposurekkaskkmanykkmetalskkandkktheirkkcompoundskkarekktoxic.

Whatkkhappenskkwhenkkankkaqueouskksolutionkkofkkakktranisitionkkelementkkionskkiskkmixedkkwithkksodium
kkhydroxidekk(NaOH)kkorkkammoniakk(NH3)?correctkkanswersAkkcolouredkkhydroxidekkprecipiatekkiskkf

ormedkkandkktakeskkthekkformkkofkk[M(H2O6)]kkn+.

, EquationkkandkkcolourkkofkkhydroxidekkprecipitatekkforkkCopperkk(II)correctkkanswersPalekkbluekksolutio
nkktokkbluekkprecipitate
[Cu(H2O6)]2+kk+kk2OH-kk-->kk[Cu(OH)2(H2O)4]kk+kk2H2O

[Cu(H2O)6]2+kk+kk2NH3kk-->kk[Cu(OH)2(H2O)4]kk+kk2NH4+

EquationkkandkkcolourkkofkkhydroxidekkprecipitatekkforkkIronkk(II)correctkkanswersPalekkgreenkksolutionk
ktokkgreenkkprecipitatekkthatkkdarkens

[Fe(H2O)6]2+kk+kk2OH-kk-->kk[Fe)OH)2(H2O)4]kk+kk2H2O

[Fe(H2O)6]2+kk+kk2NH3kk-->kk[Fe(OH)2(H2O)4]kk+kk2NH4+

EquationkkandkkcolourkkofkkhydroxidekkprecipitatekkforkkIronkk(III)correctkkanswersYellowkksolutionkktok
korangekkprecipitatekkthatkkdarkens

[Fe(H2O)6]3+kk+kk3OH-kk-->kk[Fe(OH)3(H2O)3]kk3H2O

[Fe(H2O)6]3+kk+kkNH3kk-->kk[Fe(OH)3(H2O)3]kk+kk3NH4+

EquationkkandkkcolourkkofkkhydroxidekkprecipitatekkforkkManganesekk(II)correctkkanswersPalekkpinkkkso
lutionkktokkpinkkk/kkbuffkkprecipitatekkthatkkdarkens
[Mn(H2O)6]2+kk+kk2OH-kk-->kk[Mn(OH)2(H2O)4]kk+kk2H2O

[Mn(H2O)6]2+kk+kk2NH3kk-->kk[Mn(OH)2(H2O)4]kk+kk2NH4+

EquationkkandkkcolourkkofkkhydroxidekkprecipitatekkforkkChromiumkk(III)correctkkanswersGreenkksoluti
onkktokkgreykk/kkgreenkkprecipitate
[Cr(H2O)6]3+kk+kk3OH-kk-->kk[Cr(OH)3(H2O)3]kk+kk3H2O

[Cr(H2O)63+kk+kk3NH3kk--.kk[Cr(OH)3(H2O)3kk+kk3kkNH4kk+

DefinekkcomplexkkioncorrectkkanswersAkkmetalkkionkksurroundedkkbykkcoordinatelykkbondedkkligands.

Whatkkiskkakkligand?kk(+types)correctkkanswersAtom,kkionkkorkkmoleculekkthatkkdonateskkakkpairkkofkkelect
ronskktokkakkcentralkkmetalkkatomkkorkkion.
Don'tkkalwayskkhavekktokkbekkthekksame.kkMustkkhavekkatkkleastkkonekklonekkpairkkofkkelectrons.
Monodentatekk-kkonekklonekkpair
Bidentatekk-kktwokklonekkpairskkthatkkcankkbothkkformkkbondskk
Multidentatekk-kktwokkorkkmorekkcoordinatekkbonds.

Whatkkiskkakkcoordinationkknumber?correctkkanswersThekknumberkkofkkco-
ordinatekkbondskkformedkktokkakkcentralkkmetalkkionkk/kkatom

Whatkkdoeskk6kkcoordinatekkbondskkmean?correctkkanswersOctahedralkkshape
examples:kk[Cu(H2O)6]2+.kk[Co(NH3)6]2+.kk[Cu(NH3)4(H2O)2]2+