#### Transcript The Mole - Alliance Gertz

```Subject:
Chemistry 1
(Notes)
a) How many atoms exist in a
molar Given:
mass 1of
amusubstance?
= 1.6605x10-24 g
H - Hydrogen
Mass of 1 H= 1.00 amu
= 1.00amu x 1.6605 x 10-24g/amu
= 1.6605 x 10-24 g/atom
# of atoms in 1.00 g of H= 1.00 g/1.6605 x 10-24g/atom =
= 6.02 x 1023 atoms
a) How many atoms exist in a
molar Given:
mass 1of
amusubstance?
= 1.6605x10-24 g
C - Carbon
Mass of 1 C= 12.0 amu
= 12.0amu x 1.6605 x 10-24g/amu
= 1.9926 x 10-23 g/atom
# of atoms in 12.0 g of C= 12.0 g/1.9926 x 10-23g/atom =
= 6.02 x 1023 atoms
If we use “gram” as the mass unit in
place of “amu” as in the Periodic
Table, the number of atoms is always
the same:
6.02 x 1023
This number is known as “Avogadro’s
number”. The amount of substance
involved is called a “mole”
c) The mole
= 1 Avogadro’s number of particles
A mole of H atoms is 1.0 grams of H
23 grams of
A mole of Na atoms is ____
Na.
2 moles of Na.
46 grams of Na is ____
c) The mole
A mole of H2O molecules is 18
of H2O
grams
.5 moles of H2O
9 grams of H2O is ____
2 moles of H2O
36 grams of H2O is ____
c) The mole
To calculate the number of moles, just
divide the mass by the molar mass
n = mass/molar mass
On October 23rd, at 6:02 Celebrate!
Happy Mole Day!
```