How about such as tablespoon of sugar
or a tablespoon of salt?
How will you determine the number of
particles in a tablespoon of salt?
Is the number of particles in a
tablespoon of sugar the same as the
number of particles in a tablespoon of
Lorenzo Romano Amedeo
Carlo Avogadro di Quaregna
e di Cerreto,
Count of Quaregna and Cerreto
was an Italian scientist.
He is most noted for his
contributions to molecular
theory, including what is
known as Avogadro's law.
In tribute to him,
the number of
(atoms, molecules, i
ons or other
1 mole of a
is known as
One mole of cotton has the same number
of particles as one mole of salt.
One mole of an element contains the
same number of atoms as a mole of any
1 M of a given element = 1 M of other
1 mole of a compound = 1 mole of other
1. Atomic mass of C?
2. Atomic masses of
H and O?
3. Atomic masses of
Na and Cl?
One mole of any substance
contains the same number of
What about the mass of a
mole of a substance?
Is it same for all substances?
The mass of an element or
compound depends on the mass of
Therefore, one mole of hydrogen
has a mass dependent on it atomic
mass. - MOLAR MASS
MOLAR MASS- the mass in grams
that is numerically equal to the
atomic mass. The unit of molar
mass is grams / mole (g/mol).
Answer: 12.01 amu
What is the molar mass of
The molar mass of carbon is 12.01 g.
How many atoms are I 12.01g of
6.022 x 10^23 atoms
The atomic mass of oxygen is
_______. Its molar mass is
_____________. There are ______
atoms found in ________ g of
The atomic mass of sodium is
_________. Each mole of sodium has
a mass of ______. Every ______ g of
sodium has _______ atoms.
Number of moles Cl = given mass
= 70.9 g
= 2 mol
Number of moles = given mass
1. How many moles are there in
6.05 g of carbon?
2. How many moles are there in
46.00 g of sodium?
1. Find the molar mass of water.
a. Multiply the atomic mass of H by 2 and
that of O by 1.
H = 2 x 1.008 = 2.016
O = 1 x 16.00 = 16.00
18.016 or 18.02
Number of moles (H2O) = 36.04 g
= 2.0 mol
Let’s See What You Have Learned
Α. Determine the molar masses of the
1. acetic acid (CH3COOH)
2. agua oxigenada (H2O2)
3. ammonia (NH3)
Β. Determine the number of moles in
1. 120.0 g of acetic acid
2. 17.0 g of agua oxigenada
3. 51.0 g of ammonia
♦ The mole is a unit for counting
particles in a given mass of a
substance. Each mole of a substance
is made up of 6.022 × 1023 particles.
♦ The molar mass of a substance is the
mass in grams that is numerically
equal to the atomic mass or formula
mass of the substance.
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