Using the Mole
The Mole
1 mole = 6.02 X 1023 Particles
Particle = atoms, compounds, or molecules
Molar ratio: Tells us the number of moles of
each chemical we need to use in order to have
a complete reaction (where all the chemicals
are used up.)
Atomic Molar Mass
Atomic Molar Mass: The mass of 1 mole of an
element (the mass of 6.02 X 1023 atoms of
that element)
Units: Grams/Mole ( g/mol )
Eg.1) What is the molar mass of Ca? =
Eg. 2) What is the molar mass of S? =
Atomic Molar Mass
Atomic Molar Mass: The mass of 1 mole of an
element (the mass of 6.02 X 1023 atoms of that
element)
Units: Grams/Mole ( g/mol )
Eg.1) What is the molar mass of Ca?= 40.08g/mol
Eg. 2) What is the molar mass of S? = 32.06g/mol
How do we find the molar mass of a
compound
Calculate the molar mass of
1) NaCl = Find out the number of each element is in
the compound
2) NH4Cl =
How do we find the molar mass of a
compound
Calculate the molar mass of
1) NaCl = 1Na
+ 1Cl
= Find out the mass of each element
Remember: 2 oxygens weight twice as much as one
= multiply each mass by the number of atoms in the
compound
2) NH4Cl =
How do we find the molar mass of a
compound
Calculate the molar mass of
1) NaCl = 1Na
+ 1Cl
= 1x 22.99g/mol + 1x 35.45g/mol
= Add up the mass of all the atoms
2) NH4Cl
How do we find the molar mass of a
compound
Calculate the molar mass of
1) NaCl = 1Na
+ 1Cl
= 1x 22.99g/mol + 1x 35.45g/mol
= 58.44g/mol
2) NH4Cl =
How do we find the molar mass of a
compound
Calculate the molar mass of
1) NaCl = 1Na
+ 1Cl
= 1x 22.99g/mol + 1x 35.45g/mol
= 58.44g/mol
2) NH4Cl = 1N + 4H + 1Cl
=
How do we find the molar mass of a
compound
Calculate the molar mass of
1) NaCl = 1Na
+ 1Cl
= 1x 22.99g/mol + 1x 35.45g/mol
= 58.44g/mol
2) NH4Cl = 1N + 4H + 1Cl
=1x14.01g/mol + 4x1.01g/mol + 35.45g/mol
=
How do we find the molar mass of a
compound
Calculate the molar mass of
1) NaCl = 1Na
+ 1Cl
= 1x 22.99g/mol + 1x 35.45g/mol
= 58.44g/mol
2) NH4Cl = 1N + 4H + 1Cl
=1x14.01g/mol + 4x1.01g/mol + 35.45g/mol
= 14.01g/mol + 4.04g/mol + 35.45g/mol
How do we find the molar mass of a
compound
Calculate the molar mass of
1) NaCl = 1Na
+ 1Cl
= 1x 22.99g/mol + 1x 35.45g/mol
= 58.44g/mol
2) NH4Cl = 1N + 4H + 1Cl
=1x14.01g/mol + 4x1.01g/mol + 35.45g/mol
= 14.01g/mol + 4.04g/mol + 35.45g/mol
= 53.50g/mol
How do we find the molar mass of a
compound
Calculate the molar mass of
3) Mg(NO3)2 =
4) 2CH3COOH =
How do we find the molar mass of a
compound
Calculate the molar mass of
3) Mg(NO3)2 = 1Mg + 2N
=
4) 2CH3COOH
+
6O
How do we find the molar mass of a
compound
Calculate the molar mass of
3) Mg(NO3)2 = 1Mg + 2N
+ 6O
= 1(24.31g/mol) + 2(14.01g/mol) + 6(16.00g/mol)
=
4) 2CH3COOH
How do we find the molar mass of a
compound
Calculate the molar mass of
3) Mg(NO3)2 = 1Mg + 2N
+ 6O
= 1(24.31g/mol) + 2(14.01g/mol) + 6(16.00g/mol)
= 24.31g/mol + 28.02g/mol + 96.00g/mol
4) 2CH3COOH =
How do we find the molar mass of a
compound
Calculate the molar mass of
3) Mg(NO3)2 = 1Mg + 2N
+ 6O
= 1(24.31g/mol) + 2(14.01g/mol) + 6(16.00g/mol)
= 24.31g/mol + 28.02g/mol + 96.00g/mol
= 148.33
4) 2CH3COOH = 2 (2C + 4H + 2O)
=
How do we find the molar mass of a
compound
Calculate the molar mass of
3) Mg(NO3)2 = 1Mg + 2N
+ 6O
= 1(24.31g/mol) + 2(14.01g/mol) + 6(16.00g/mol)
= 24.31g/mol + 28.02g/mol + 96.00g/mol
4) 2CH3COOH = 2 (2C + 4H + 2O)
= 2 (2(12.01g/mol) + 4(1.01g/mol) + 2(16.00g/mol))
=
How do we find the molar mass of a
compound
Calculate the molar mass of
3) Mg(NO3)2 = 1Mg + 2N
+ 6O
= 1(24.31g/mol) + 2(14.01g/mol) + 6(16.00g/mol)
= 24.31g/mol + 28.02g/mol + 96.00g/mol
4) 2CH3COOH = 2 (2C + 4H + 2O)
=2 (2(12.01g/mol) + 4(1.01g/mol) + 2(16.00g/mol))
= 2 (24.02g/mol + 4.04g/mol + 32.00g/mol)
= 2(60.06g/mol)
= 120.12g/mol
Assignment
Worksheet on conversions
Next Class: Lab on Moles of Iron page 55 in
Heath Chemistry Laboratory Experiments