Chemistry11

MoleIIIName:Date:Block:

1. RelativeAtomicMass2. TheMole3. MolarMass

RelativeAtomicMassMass:Theamountof_______________inanobject.AtomicMass:

• Themassofaparticularatom.

• Theatomicmassisfoundbycomparingthemassofanelementtothemassofanatomofcarbon-12.Carbon-12isassignedanatomicmassofexactly_________________.

• Themassofoneindividualatomisextremelysmall.Alargenumberofatomsisneededtoprovideenough

masstomeasure.

• Amoleis…

TheMole

THEMOLE

Avogadro’sNumber1mole=6.02214179x1023items

**items=atoms/molecules/particlesetcTheabbreviationfortheunitmoleis___________.

Thinkabouttheterm“dozen”.Wecansay……adozeneggs=12eggs…adozenbooks=12booksSimilarly,amoleofparticles=6.02x1023particles…amoleofeggs=6.02x1023eggs

HOWBIGISTHEMOLE?

Ifyouwereabletocountatomsattherateof10millionpersecond,itwouldtakeabout2billionyearstocounttheatomsin

onemole.

IfyouhadAvogadro’snumberofunpoppedpopcornkernels,and

spreadthemacrosstheUS,thecountrywouldbecoveredinpopcorntoa

depthof9miles.

Onemoleofsecondsisabout19quadrillion

years,or4240666timestheageoftheEarth,or954150timestheageof

theuniverse.

OnemoleofdonutsdividedequallyamongEarth’speople,eachpersonwouldhave90trilliondonuts.

Onemoleofpaperwould

makeastackthatwouldreachtothemoonmorethan80billion

times.

PracticeProblems:1. Howmanylithiumatomsarein3.2moloflithium?

2. Findthenumberofchromiumionsin3.5molofchromiumions.

3. Howmanyatomsarein0.23molofNaCl?

4. 7.3x1024carbonmonoxidemoleculesrepresenthowmanymolesofcarbonmonoxide?

5. Howmanymolesofargondo1.81x1022atomsofargonrepresent?

6. Howmanyhydrogenatomsaretherein1.0moleofwater?Howmanyoxygenatomsaretherein1.0moleofwater?Whatistheratioofhydrogenatomstooxygenatoms?

Movie:HowBigIsaMole(https://www.youtube.com/watch?v=TEl4jeETVmg)MolarMass

Eachelementhasauniqueatomicmass.Eachcompoundhasauniquemolecularmass.

WHATISMOLECULARMASS?•

• Unit=• Example:

o H2OWHATISMOLARMASS?

•

• Itisa________________________________________________________________.

Example:WhatisthemolarmassofMgCl2?

• #ofMgatoms=• AtomicmassofMg=• #ofClatoms=• AtomicmassofCl=

• Molarmass=

WhatisthemolarmassofAl2(SO4)3?• #ofAlatoms=• AtomicmassofAl=• #ofSatoms=• AtomicmassofS=• #ofOatoms=• AtomicmassofO=

• Molarmass=

PracticeProblemI:(FindtheMolarMass)

7. WhatisthemolarmassofNa2Cr2O7?

8. Whatisthemolarmassofiron(III)sulphide?

9. Whatisthemolarmassofammoniumnitrate?

10. Whatisthemolarmassofpropane,C3H8?

Compound Formula MolarMass(g/mol)

a) Na2O ---

b) Cu(NO3)2 ---

c) Calciumchloride

d) Iron(II)oxide

e) Iron(III)oxide

f) Copper(I)nitride

g) Potassiumpermanganate

h) KBr ---

i) Nitrogengas

j) Argongas

k) H2SO4 ---

a)61.98g/molb)187.57g/molc)110.98g/mold)71.85g/mole)159.70g/molf)204.66g/molg)158.04g/molh)119.00g/moli)28.02g/molj)39.95g/molk)98.09g/mol

PracticeProblemII:(Conversions+MolarMass)11. Findthemassof4.60molesofCa(OH)2.

12. Calculatethenumberofmolespresentina358.0gramsampleofsodiumcarbonate.

13. Howmuchwouldasampleof7.4molofMgOweighinkilograms?

14. AsampleofCoCl2weighs4524grams.HowmanymolofCoCl2areinthissample?

15. Howmanymolesofwaterarein1.8gofwater?

16. Verylargequantitiesofchemicalsareproducedinthechemicalindustry.Worldwideproductionofsulphuricacid(H2SO4)isestimatedattwotrillion(2.0x1012)molesannually.HowmanytonnesofH2SO4isthis?(1tonne=1000kg)

17. Amassofa0.0150molsampleofagasthatisknowntohavesulfurandoxygenhasamassof0.9615g.a) Findthemolarmassofthisgas.

b) Determinethemolecularformulaforthisgas.Writetheformulaeforseveralpossiblecompoundsofsulfurandoxygen,startingwiththesimplest.Calculatethemolarmassforeachoneandfindwhichonematcheswiththecalculatedmolarmassin(a).

PossibleFormulaforS&O

MolarMass Correct?

Themolecularformulaforthecompoundis__________.

18. Howmanymoleculesarein200.0gofNaCl?

19. Howmanyatomsarein2moleculesofHg(IO3)2?

20. Howmanymoleculesarein64.0gofFeS?

21. Howmanymolesarein2.75x1023atomsofFe?

22. Whatisthemassof3.00x1022atomsofPt?

23. Whatisthedensityofaceticacid,CH3COOH,if0.250molhasavolumeof14.3mL?

24. Howmanymolesarein85.0mgofCuSCN?

1)1.9x1024atoms2)2.1x1024ions3)2.8x1023atoms4)12mol5)0.0301mol6)1.2x1024atoms,6.0x1023atoms,ratiois2:17)261.98g/mol8)207.91g/mol9)80.06g/mol10)44.11g/mol11)341g12)3.378mol13)0.30kg14)34.85mol15)0.10mol16)2.0x108tonnes17)64.1g/mol,SO218)2.061x1024molecules19)18atoms20)4.38x1023molecules21)0.457moles22)9.72g23)1.05g/mL24)6.99x10-4mol