THE MOLE
What a fun concept
WHAT IS A MOLE?
A burrowing critter?
 A skin pigmentation?
 A word that evokes an enormous number?

1 mole of any substance equals 6.02 x 1023
representative particles of that substance
 6.02 x 1023 is known as Avogadro’s number

WHAT IS A REPRESENTATIVE
PARTICLE?
It depends on what the substance is
 What can a substance be?


Element


Molecular compound


Anything but the BrINClHOF elements which are diatomic
molecules in nature
Made of two or more nonmetals…includes BrINClHOF
elements with their subscripts of 2
Ionic compound

Made of a metal and a nonmetal or contains a polyatomic
ion
A HANDY LITTLE CHART
Substance
Representative Particle Smaller bits
(rp)
Element
Atom
Molecular Compound
Molecule
Atoms
Ionic Compound
Formula Unit
Ions
SO, HERE WE GO…

1 mol of Fe contains 6.02 x 1023 atoms of Fe

1 mol of Br2 contains 6.02 x 1023 molecules of Br2



1 mol of NaCl contains 6.02 x 1023 formula units
of NaCl
1 mol of SO3 contains 6.02 x 1023 molecules of SO3
1 mol of Na2O contains 6.02 x 1023 formula units
of Na2O
AND WE MAKE THAT INFO USEFUL
BY WRITING IT AS…





1 mol Fe
6.02 x 1023 atoms Fe
1 mol of Br2
6.02 x 1023 molec Br2
1 mol of NaCl
6.02 x 1023 fu NaCl
1 mol of SO3
6.02 x 1023 molec SO3
1 mol Na2O
6.02 x 1023 fu Na2O
OR WE CAN FLIP THEM TO GET…





6.02 x 1023 atoms Fe
1 mol Fe
6.02 x 1023 molec Br2
1 mol of Br2
6.02 x 1023 fu NaCl
1 mol of NaCl
6.02 x 1023 molec SO3
1 mol of SO3
6.02 x 1023 fu Na2O
1 mol Na2O
SMALLER BITS?

Only for molecules and formula units

1 molec Br2 has 2 atoms of Br

1 fu NaCl has 1 Na1+ ion and 1 Cl1- ion

1 molec SO3 has 1 S atom and 3 O atoms

1 fu Na2O has 2 Na1+ ions and 1 O2- ion
MOLAR MASS

The mass of one mole of a substance
Use average atomic masses from the periodic table
and round their masses to the hundredths place for
consistency
 Unit is g/mol


1 mol Fe = 55.85 g Fe …55.85 g Fe = 1 mol Fe

1 mol Fe
55.85 g Fe
or
55.85 g Fe
1 mol Fe
MOLAR MASS OF A COMPOUND
For a compound, you must calculate the molar mass
 Molar Mass of Br2

Br---2 x 79.90 = 159.80 g/mol

1 mol Br2
159.80 g Br2
or
159.80 g Br2
1 mol Br2
MOLAR MASS OF A COMPOUND

Molar Mass of NaCl
Na---1 x 22.99 = 22.99
Cl--- 1 x 35.45 = 35.45
58.44 g/mol

1 mol NaCl
58.44 g NaCl
or
58.44 g NaCl
1 mol NaCl
MOLAR MASS OF A COMPOUND

Molar Mass of SO3
S---1 x 32.06 = 32.06
O---3 x 16.00 = 48.00
80.06 g/mol

1 mol SO3
80.06 g SO3
or
80.06g SO3
1 mol SO3
MOLAR MASS OF A COMPOUND

Molar Mass of Na2O
Na---2 x 22.99 = 45.98
O--- 1 x 16.00 = 16.00
61.98 g/mol

1 mol Na2O
61.98 g Na2O
or
61.98 g Na2O
1 mol Na2O
MOLAR MASS OF A COMPOUND

Molar Mass of Ca(OH)2
Ca---1 x 40.08 = 40.08
O--- 2 x 16.00 = 32.00
H--- 2 x 1.01 = 2.02
74.10 g/mol

1 mol Ca(OH)2 or
74.10 g Ca(OH)2
74.10 g Ca(OH)2
1 mol Ca(OH)2
MOLAR MASS OF A COMPOUND

Molar Mass of Mg(C2H3O2)2
Mg---1 x 40.08 = 24.31
C--- 4 x 12.00 = 48.00
H--- 6 x 1.01 = 6.06
O--- 4 x 16.00 = 64.00
142.37 g/mol

1 mol Mg(C2H3O2)2
142.37 g Mg(C2H3O2)2
or
142.37 g Mg(C2H3O2)2
1 mol Mg(C2H3O2)2
ANOTHER HANDY CHART
rp
1 mol
mass
AND NOW, YOU PUT IT ALL
TOGETHER

How many atoms of helium are in 4.50 mol of
helium?
Is helium an element, molecular compound, or ionic
compound?
 What is its representative particle?
 Use your given information to begin your dimensional
analysis or unit conversion…always write a number,
unit, and substance

4.50 mol He x 6.02 x 1023 atoms He = 2.71 x 1024 atoms He
1 mol He
SO, HAVE FUN

If a sample of chlorine gas contains 2.97 x 1024
atoms of Cl, how many moles of chlorine gas are
there?
Is chlorine gas an element, molecular compound, or ionic
compound?
 What is its representative particle?
 Use your given information to begin your dimensional
analysis or unit conversion…always write a number,
unit, and substance

2.97 x 1024 atoms Cl x 1 molec Cl2 x 1 mol Cl2
=
2 atoms Cl 6.02 x 1023 molec Cl2
PRACTICING

How many sulfide ions are present in 10.0 g of ferric
sulfide?
Is ferric sulfide an element, molecular compound, or
ionic compound?
 What is its representative particle?
 Use your given information to begin your dimensional
analysis or unit conversion…always write a number,
unit, and substance

10.0 g Fe2S3 x 1 mol Fe2S3 x 6.02 x 1023 fu Fe2S3 x
207.88 g Fe2S3 1 mol Fe2S3
3 ions S21 fu Fe2S3
=