The Mole
The mighty mole!
Lecture of 10-19
Take out your
calculator and
periodic table.
A mole of balloons = 6.02214179×1023 balloons
Amedeo Avogadro also known as
Lorenzo Romano Amedeo Carlo Avogadro di Quaregna (Quaregga) e di Cerreto
Born here:
Avagadro figured out
That the number of elementary entities in 1 mole
of a substance = 6.02214179×1023
You can have a mole of ions, mole of molecules,
mole of atoms, mole of anything!
Fun facts to know and tell
• Avogadro lived in
Italy in a region that
became annexed by
France when
Napoleon came to
power… so his
famous paper was
published in French.
1mole = atomic mass of something
in grams…
• AND if you have the atomic mass of
something in grams, you know that there are
6.02x1023 atoms in there!
• Doesn’t that blow your mind?
Why ‘mole?’
• The word 'mole' is easier to say and write than
‘6.02x1023’
• Mole day is October 23rd.
• Celebrated annually on October 23 from 6:02 a.m.
to 6:02 p.m., Mole Day commemorates Avogadro’s
Number (6.02 x 1023),
Also! 1 mole of any gas has a volume
of 22.4 liters.
• One mole of any gas will occupy 22.4 liters.
• Doesn’t this blow your mind?
This is useful knowledge (given the volume of a
gas? You can divide by 22.4 to find the number
of moles… given moles? Find the volume!):
Keep this in your mind:
Grams ↔ mole ↔ # of particles
liters
Pledges from the National Mole day website:
I pledge allegiance to the mole, and to the science from
which it comes, one SI unit, extremely divisible, with
micromoles and mill moles for all. (Provided by R. Thomas
Myers - Kent State University, Kent, OH)
I pledge allegiance to the mole, to the International Union
of Pure and Applied Chemistry, and to the atomic mass
for which it stands, one number, most divisible, with
atoms and molecules for all. (Provided by Sylvia Cooper Morgantown High School, Morgantown, WV)
[How many moles of Pb are in 9.3 X 1015
atoms of Pb?]
A. [9.3 X 1015]
B. [6.02 X 1023 ]
C. [1.5 X 10-8]
D. [1.5 X 108]
9.3 X 1015 atoms X 1.0 mol Pb
1
6.02 X 1023 atoms Pb
[How many moles of Pb are in 9.3 X 1015
atoms of Pb?]
A. [9.3 X 1015]
B. [6.02 X 1023 ]
C. [1.5 X 10-8]
D. [1.5 X 108]
9.3 X 1015 atoms X 1.0 mol Pb
1
6.02 X 1023 atoms Pb
[What is the molar mass of ethane (C2H6)?]
A. [24g]
B. [30g]
C. [13g]
D. [6 g]
2 mol C X 12.0 g C = 24 g C
1 mol
Molar mass of C2H2 = 30g
+ 6 mol H X 1.0 g H = 6 g H
1mol
[What is the molar mass of K2SO4]
A. [atomic mass of 2 potassium + atomic mass
of sulfur + atomic mass of 4 oxygen]
B. [39.1 + 39.1 + 32.1 + 16 +16 +16 + 16]
C. [174.3 g ]
D. [all of the above]
[Find the mass of 3.65 X 10-2 mol K2SO4]
A. [6.36 g K2SO4]
B. [6.36 K2SO4]
C. [636 g K2SO4]
D. [6.36 mol K2SO4]
3.65 X 10-2 mol K2SO4 X 174.3 g K2SO4
1 mol K2SO4
=636 X 10-2 g K2SO4 =6.36 g K2SO4
[how many particles are there in
2.5 mol H2O2?]
A. [15.05 X 1023 representative particles (atoms)]
B. [1.5 X 10 24 representative particles (atoms)]
C. [6.02 X 1023 representative particles (atoms)]
D. [A and B are correct]
2.5 mol H2O2 X 6.02 X 1023 representative particles (atoms)
1 mol
=1.5 X 10 24 representative particles (atoms)
[what is the volume of any mole of any
gas at standard temperature and
pressure (STP)?]
A. [22.4 liters]
B. [atomic mass in liters]
C. [atomic mass in grams]
D. [6.02 X 1023 representative particles (atoms)]
[What is the volume of 2.5 mol NaCl?]
A. [5.0 mol/liter]
B. [56 L]
C. [44.8 L]
D. [2.5 mol/liter]
2.5 mol X 22.4 L
1 mol
[What is the density of N2O, a gas,
at STP?]
A. [14.0 g +14.0 g +16.0 g =44.0 grams]
B. [22.4 liters]
C. [44.0 g/22.4 l = 1.96g/l]
D. [none of the above]
Density = Mass/volume
[What is the mass of 2 moles of NaCl?]
A. [23.0g + 35.5g = 58.5g]
B. [(23.0g + 35.5g) X 2 =117g]
C. [22.4 g + 22.4g +22.4 g + 22.4 g = 89.6g]
D. [none of the above]
[what is the volume of 16g of O2 at
STP?]
A. [32g]
B. [44.8L]
C. [11.2 L]
D. [22.4L]
Mass of O2 = 2 (16.0g/mol) =32.0 g/mol
16g/32g/mol = 0.500 mol
To find the volume, 0.500 X 22.4L
[How many moles are in 16 grams
of O2?]
A. [1]
B. [0.5]
C. [2]
D. [1.5]