THE MOLEChapter 7

CONCEPT MAP

The mole

Can be converted to

Similar to:

Dozen/ Gross/ set/ pair

6.02x10 ^23

Particles- atoms, molecules, etc.Molar Mass

Mass- g,mg,kg,etc.

MOLAR MASS

Molar Mass = # OF GRAMS1 MOLE

How to calculate Molar Mass-

~ Average atomic mass for each element is on the periodic table1. Count the number of atoms for each element2. Multiply the number of atoms by the avg. atomic mass 3. Add together all the atomic masses

Example:H2O= H: 2 (1.001794 g/mol)= 2.003588

O: 1 (15.9994 g/mol) = 15.999418.002988 g/mol

AVOGADRO’S NUMBER

A counting number used to tell how many particles.

Avogadro’s number = 6.02 x10 ^23 ‘atoms’ 1 mole

Just like there are 12 eggs in a dozen, there are 6.02 x 10^23 eggs in a mole.

It is a constant!

CONVERT FROM GRAMS TO MOLES

# of grams x 1 mole = # of moles molar mass (g)

Example: How many moles are in 25 grams of water?

25 grams x 1 mole = 1.38 moles 18 grams

Molar Mass of H2O=H: 2x 1.01= 2.02O: 1x 15.99=15.99

18.01~ 18 g/mol

CONVERT FROM MOLES TO GRAMS# of moles x molar mass (g) = #

grams 1 mole

Example: How many grams are in 30 moles of water?

30 moles x 18 grams = 540 grams 1 mole

CONVERT FROM GRAMS TO ATOMS OR MOLECULES

# of grams x 1 mole x 6.02x10^23atoms = # atoms molar mass 1 mole

Molecule= compound

Atoms= one element

Example: How many molecules of NaCl are in 15 grams?

15 grams x 1 mole x 6.02 x 10^23 molecules=1.55x10^23molecules

58 grams 1 mole

Molar Mass of NaCl:Na: 1x 22.989 = 22.989 gCl: 1x 35.45 =35.45g

58.43 ~ 58 g/mole

CONVERT FROM MOLES TO ATOMS/MOLECULES

#moles x 6.02x10^23 atoms = # of atoms 1 mole

Example: How many atoms are in 5 moles of NaCl?

5 moles x 6.02x10^23 atoms = 3.01 x10^24 1mole