Transcript WHAT IS A MOLE?

WHAT IS A MOLE?
 602214199000000000000000
 6.02 x 1023
Mole Facts
 6.02 X 1023 Pennies: Would make at least 7
stacks that would reach the moon.
 6.02 X 1023 Watermelon Seeds: Would be found
inside a melon slightly larger than the moon.
 6.02 X 1023 Blood Cells: Would be more than the
total number of blood cells found in every human
on earth.
 1 Liter bottle of Water contains 55.5 moles H20
A Brief History…
 Amadeo Avogadro was an Italian physics professor who
proposed in 1811 that equal volumes of different gases at
the same temperature contain equal numbers of molecules
 Josef Loschmidt, an Austrian high school teacher,in 1865,
calculated the number of molecules in one cm3 of gaseous
substance to be somewhere around 2.6 x 1019
 J.Perrin (1908) estimated the value to be between 6.5 x
1023 and 6.9 x 1023
 Rutherford and Geiger used radioactive methods: 6.2 x
1023
 The best modern values for what we now call "Avogadro's
Number" are the result of the x-ray diffraction
measurement of lattice distances in metals and salts.
Definition of a Mole
 The amount of atoms in 12.0 grams of
Carbon 12 (6.02 x 1023 atoms known as
Avogadro’s number).
 A sample of any element with a mass equal
to that element's atomic weight (in grams)
will contain precisely one mole of atoms
(6.02 x 1023 atoms).
How do we determine MOLAR
MASS?
 Molar Mass: Mass in grams of one mole of that
substance
 What is the molar mass of H2O?
2 Hydrogen atoms: 2 x 1g = 2g
1 Oxygen atom: 1x 16g = 16g
1 mole H2O = 18g
 What is the molar mass of CO2?
 Fe2O3?
Why is the mole an important
unit in chemistry?
Atoms and molecules react with one another
particle by particle
The mole is the translation factor between
weights and numbers of particles
How do we convert mass to
particles?
How many moles in 10 g of O2?
10g O2 x 1 mole
32g
= 0.3125 mol
How many molecules in 55 g of H2O?
55g H2O x 1mole x 6.02 • 1023
18g
1mole
= 18.4 • 1023 = 1.84 • 1024 molecules