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Mr. ShieldsMr. Shields Regents Chemistry Regents Chemistry U04 L03 U04 L03

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What Are Mole Conversions?What Are Mole Conversions?

We’re now going to look at some useful

Relationships (that is conversions).

Actually, we’ve already done some of these!

MassMass # of Particles# of Particles

VolumeVolume

MolesMoles

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Chem ConversionsChem Conversions

We know 1 mole = 6.023 x 1023 particlesThis is Avogadro’s number (NA)

We also know 1 mole = 22.4 litersThis is the Molar Volume (Vm)

We also know that 1 mole = Molar Mass

So, “How do we convert from one value to another”?

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We Use the “Conversion Chart”We Use the “Conversion Chart”

AKA - The Mole MapAKA - The Mole Map

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Mole ConversionsMole Conversions

RULE 1RULE 1: : ALL conversionsALL conversions TO MOLESTO MOLES involveinvolve DIVISIONDIVISION

RULE 2RULE 2: : ALL conversionsALL conversions FROM MOLESFROM MOLES to MASS, VOLUME,to MASS, VOLUME, or # OF PARTICLES involveor # OF PARTICLES involve MULTIPLICATIONMULTIPLICATION

““Moles leave theMoles leave the mole hole to Multiply”mole hole to Multiply”

MassMass # of Particles# of Particles

VolumeVolume

MolesMoles

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Converting Moles to Particles Converting Moles to Particles (There and back again)(There and back again)

Remember 6.02 X 10Remember 6.02 X 102323 = 1 mole of anything = 1 mole of anythingAtom, molecules, protons, ions, marblesAtom, molecules, protons, ions, marbles

Take a look at the Mole MapTake a look at the Mole Map

– Particles to Moles:Particles to Moles: (into the mole hole) (into the mole hole) Divide the # of Divide the # of Particles by 6.022 x 10Particles by 6.022 x 102323

– Moles to Particles:Moles to Particles: (out of the mole hole) (out of the mole hole) Multiply the # of Multiply the # of moles by 6.022 x 10moles by 6.022 x 102323

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Mole/Particle ConversionsMole/Particle Conversions

1. How many molecules are there in 4.0 moles of H1. How many molecules are there in 4.0 moles of H22OO22? ?

# of molecules = 4.0 moles x # of molecules = 4.0 moles x 6.02 x 106.02 x 102323 particles particles 1 mole1 mole

= 24 x 10= 24 x 102323 = = 2.4 x 102.4 x 1024 24 particlesparticles

2. How many moles are there in 7.14 x 102. How many moles are there in 7.14 x 102323 molecules? molecules?

# of moles = 7.14 x 10# of moles = 7.14 x 102323 particles / particles / 6.02 x 106.02 x 102323 particles particles 1 mole1 mole

= = 1.19 moles1.19 moles

Try this ….Try this ….

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Mole/Particle ConversionsMole/Particle Conversions

How many How many atomsatoms are in 3 moles of sugar are in 3 moles of sugar (C(C1212HH2424OO1111)?)?

3 moles of sugar X 3 moles of sugar X 6.02 X 106.02 X 102323 Mole of sugar

= 18.06 X 1023 = 1.806 X 1024 molecules of sugar

#atoms = 47 x 1.806 x 1024 = 8.49 x 1025

How about this one?How about this one?

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Mole/Mass ConversionsMole/Mass Conversions

Look at the Conversion Chart Again…Look at the Conversion Chart Again…

– Mass to MolesMass to Moles: : Divide mass by molar massDivide mass by molar mass – Moles to MassMoles to Mass: : Multiply moles by molar massMultiply moles by molar mass

MassMass # of Particles# of Particles

VolumeVolume

MolesMoles

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Mole/Mass ConversionsMole/Mass ConversionsYou’re going to need to use the You’re going to need to use the Periodic Periodic

TableTable for any conversion involving for any conversion involving massmass

because we need to 1because we need to 1stst calculate calculate Molar massMolar mass

How many moles of CoCl2.6H2O are there in 160g?

Molar mass = 58.933 + 2x35.453 + 12x1.008 + 6x15.999= 237.881 g/mol

# of moles = 160g / 237.881 g/mol = 0.67 moles

(We’re going into the mole hole so we’re going to(We’re going into the mole hole so we’re going tobe dividing)be dividing)

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Mole/Mass ConversionsMole/Mass Conversions

How many grams are in 0.954 moles of CuSO4 ?

(Remember … We’re leaving the mole hole so we’ll be multiplying)

First find the molar mass of the CuSO4 compound.

Cu = 63.5 S = 32.1 4O = 64

Molar mass of CuSO4 = 159.6 g/mol 0.954mol x 159.6 g/mol = 152.26 g

Let’s now convert moles to grams …Let’s now convert moles to grams …

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ProblemsProblems

1. How many atoms are there in 98.5 grams of tin ?

2. How many atoms are there in 20 grams of H20 ?

Gram Atomic mass of Tin = 118.71 grams98.5/118.71 = 0.83 moles0.83 moles x 6.022 x 1023 atoms/mole = 5.0 x 1023 atoms

gram molecular mass of water = 18 grams20g/18g = 1.11 moles1.11 moles x 6.022 x 1023 = 6.69 x 1023 molecules H203 x 6.69 x 1023 molecules = 2.0 x 1024 atoms

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ProblemsProblemsHere’s another problem:

Which sample contains the same number of atoms as4g of Lithium?

1) 1.16g He 2) 20.18g Ne 3) 17.96g P 4) 10.46g Be

ANS: Gram Atomic mass of Li = 6.94 g4 g/6.94 g = 0.58 moles

Atomic Mass He (4.00) Ne (20.18) P (30.97) Be (9.01)

Mol of He = 1.16/4 = 0.29 Mol of Ne = 20.18/20.18 = 1Mol of P = 17.96/30.97 = 0.58Mol of Be = 10.46/9.01 = 1.16

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Volume/Mole ConversionsVolume/Mole Conversions

OK. Now lets convert between Volume and moles.OK. Now lets convert between Volume and moles.Look at the Conversion Chart …Look at the Conversion Chart …

Volume to MolesVolume to Moles: :

VVmm = 22.4L / mole at = 22.4L / mole at STPSTP

Moles to VolumeMoles to Volume::

These calculations are independent of what gasThese calculations are independent of what gasIs involved Ex. NHIs involved Ex. NH33, CO, CO22, H, H22 etc. etc.

MultiplyMultiply mol by molar volume mol by molar volume

DivideDivide volume by molar volume volume by molar volume

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Volume/Mole ConversionVolume/Mole Conversion

Problem:Problem:

How many liters are occupied by 3.5mol of NHHow many liters are occupied by 3.5mol of NH33 at STP? at STP?

3.5 mol x 3.5 mol x 22.4L22.4L = 78.4L = 78.4L 1 mol1 mol

How many moles are there in 6.5L of NHow many moles are there in 6.5L of N22? How many? How manygrams are there? grams are there?

6.5L / 22.4L = .29 mol6.5L / 22.4L = .29 mol

0.29 mol x 28.02g/mol = 8.13g0.29 mol x 28.02g/mol = 8.13g