Second Semester Final Exam Study Guide€¦ · Second Semester Final Exam Study Guide Unit 6 Know...

SecondSemesterFinalExamStudyGuide

Unit6Knowhowtonamecompoundsandwritechemicalformulas.

a) Howdoyoudetermineifacompoundisionicormolecular?Ionic:betweenacationandananion(metalandnon-metal,metalandpolyatomic,polyatomicandpolyatomic)Molecular:betweentwononmetals

b) Whatdoyouneedtokeepinmindwhenwritingchemicalformulasforioniccompounds?Writingchemicalformulasforionic–youneedtomakesureyoucriss-crosschargestocreateneutralcompounds

c) Whatdoyouneedtokeepinmindwhennamingmolecularcompounds?Namingmolecularcompounds–youneedtoidentifythenumberofeachatominthecompoundanduseprefixesforboththefirstandsecondelement(firstelementdoesnotusemono-)

d) Whenapolyatomicionisinvolved,whattypeofbondisoccurring?CompoundsthatinvolvepolyatomicIONSarealwaysioniccompounds.

e) Writethechemicalformulasforthefollowingcompounds.*Youshouldidentifyiftheyareionicormolecularfirst*

copper(I)bromide-Ionic:CuBr magnesiumoxide-Ionic:MgO ammoniumsulfate-Ionic:(NH4)2SO4 diphosphoroustrioxide–Molecular:P2O3 sulfurtrichloride–Molecular:SCl3 manganese(III)cyanide–Ionic:Mn(CN)3

f) Writethenamesforthefollowingcompounds.*Youshouldidentifyiftheyareionicormolecularfirst* AlF3–Ionic:AluminumFluoride Fe(ClO4)3–Ionic:Iron(III)perchlorate NO3–Molecular:Nitrogentrioxide Li(OH)–Ionic:Lithiumhydroxide Sr(NO2)2–Ionic:Strontiumnitrite CI5–Molecular:CarbonpentiodideKnowhowtotranslatechemicalreactions,balanceequations,andpredictchemicalreactions.Writethefollowingchemicalreactionsintochemicalformulasandafullchemicalequation.

a) Sulfurburnsinoxygengastoproducesulfurdioxide.S+O2àSO2

b) Sulfuricacid(H2SO4)andsodiumhydroxidereactiontogetherforformsodiumsulfateandwater.

H2SO4+2NaOHàNa2SO4+2H2O

c) Sodiumoxidereactswithwatertoproducesodiumhydroxide.Na2O+H2Oà2NaOH

d) Zincsulfidereactswithoxygengastoproducezincoxideandsulfurdioxide.

2ZnS+3O2à2ZnO+2SO2Balancethefollowingchemicalequations:

e) N2+3H2à2NH3f) 3Zn+2MoO3à___Mo2O3+3ZnOg) P2O5+H2OàP(OH)3-unabletobalance! h) Cd(NO3)2+Na2Sà CdS+2NaNO3 i) Na2O+H2Oà2NaOH

Identifythetypeofequationthatwilloccurusingthereactants.Thenpredicttheproductsandbalancetheequation.

j) C6H12 + 9O2 →6CO2+6H2O(Combustion)k) CuCl2 + H2S →CuS+2HCl(DoubleDisplacement)

l) CaCl2 + K2CO3 →CaCO3+2KCl(DoubelDisplacement)m) Al + O2 →Al2O3(Synthesis)n) Al2(CO3)3 →Al2O3+CO2(Decomposition)

Knowhowtouseabalancedequationandamolemaptoconvertfromonesubstancetoanother(stoichiometry).

2Cr+3CuSO4à3Cu+Cr2(SO4)3a) Howmanygramsofcopperwouldbeproducedfrom49.48gramsofchromium?

!".!" !"#$% !"

! × ! !"# !!

!".! !"#$% × ! !"# !"

! !"#$ !" × !".!! !"#$% !"

! !"# !"=82.46gramsCu

b) Howmanygramsofchromiumarerequiredtoreactwith125mLofCuSO4?

!"# !" !" !"#$!

! × ! !

!""" !" × ! !"# !"#$!

!!.! ! × ! !"# !"

! !"#$ !"#$! × !".! !"#$% !"

! !"# !"=0.1934gramsCr

2ZnS+3O2à2ZnO+2SO2

c) Howmanylitersofsulfurdioxidearecreatedwhen12.6Lofoxygengasreactswithzincsulfide?

!".! ! !!!

× ! !"# !!!!.! !

× ! !"# !"!! !"#$ !!

× !!.! ! !"!! !"# !"!

=8.4LofSO2

d) If3.45x1018atomsofzincsulfidereactwithoxygengas,muchmanymolesofzincoxideareproduced?

!.!" ! !"!" !"#$% !"#!

× ! !"# !"#!.!"" ! !"!"!"#$% !"#

× ! !"# !"#! !"#$ !"#

=0.57x10-5atoms=5.7x10-6atoms

e) When54gramsofoxygengasreactwithzincsulfide,howmanyatomsofsulfurdioxideareproduced?

!"!"#$% !!!

× ! !"# !!!".! !"#$% !!

× ! !"# !"!! !"#$ !!

× !.!"" ! !"!"!"#$% !"!! !"# !"!

=6.77x1023atomsSO2

2NaClO3à2NaCl+3O2f) WhatisthemoleratiobetweenNaClO3andNaCl?

2molesNaClO3:2NaCl

g) 12molesofNaClO3willproducehowmanygramsofO2?

!" !"#$% !"#$%!

! × ! !"# !!

! !"#$ !"#$%! × !".! !"#$% !!

! !"# !!=576gramsO2

h) Ifyouhave24.7gramsNaClO3howmanygramsofNaClwillbeproduced?

!".! !"#$% !"#$%!!

× ! !"# !"#$%!!"#.!! !"#$% !"#$%!

× ! !"# !"#$! !"#$ !"#$%!

× !".!! !"#$% !"#$! !"# !"#$

=13.56gramsNaCl

i) Ifyouhave10gramsNaClO3,howmanylitersofoxygengaswillbeproduced?

!" !"#�! !"#$%!!

× ! !"# !"#$%!!"#.!! !"#$% !"#$%!

× ! !"# !!! !"#$ !"#$%!

× !!.! ! !!! !"#$!

=3.16LO2

Knowhowtodeterminelimitingandexcessreactants.

2ZnS+3O2à2ZnO+2SO2a) 6.45gramsofzincsulfidereactswith9.20gramsofoxygengastoproducezincoxide.Howmanygramsof

ZnOareformed?

!.!" !"#$% !"#!

× ! !"# !"#!".!" !"#$% !"#

× ! !"# !"#! !"#$ !"#

× !".!" !"#$% !"#$! !"# !"#

=5.39gramsNaCl

!.!"!"#$% !!!

× ! !"# !!!".! !"#$% !!

× ! !"# !"#! !"#$ !!

× !".!" !"#$% !"#$! !"# !"#

=15.6gramsNaCl

b) Whatisthelimitingandexcessreactant? Thelimitingreactantiszincsulfide(ZnS).

c) Theactualyieldofthisreactionis12.5grams.Whatisthepercentyieldofthisreaction?

!.!" !"#$%!".! !"#$%

× 100=43.12%yieldKnowhowtocalculatethepercentagecompositionofasubstance.

a) WhatisthepercentagecompositionofnitrogeninthecompoundHNO3? H:1x1.01=1.01grams !.!" !"#$%

!".!" !"#$%× 100=1.6%hydrogen

N:1x14.01=14.01grams !".!" !"#$%!".!" !"#$%

× 100=22.2%nitrogen

O:3x16.0=48grams !" !"�!"!".!" !"#$%

× 100=76.2%oxygen HNO3=63.02gramstotal

b) An8.20gramspieceofMgcombinescompletelywith5.40gramsofOtoformacompound.WhatisthepercentagecompositiononMgandOinthiscompound?

8.20grams+5.40grams=13.6grams !.!" !"#$%

!".! !"#$%× 100=60.3%Mg

!.!" !"#$%

!".! !"#$%× 100=39.7%O

c) 9.03gramsofMgcombinescompletelywith3.48gramsofNtoformacompound.Whatisthepercentage

compositionofMgandNinthecompound?*Hint:writeoutcompoundandfindmolarmass* Mg2N3=90.65grams Mg=48.62grams !".!" !"#$%

!".!" !"#$%× 100=53.6%Mg

N=42.03grams !".!" !"#$%!".!" !"#$%

× 100=46.4%N