Aim: What is the Mole?

Do Now: Using conversion factors convert the following:1.How many inches are there in 45.6 cm? (2.54 cm = 1 in.)2.How many centimeters are there in 1.23 x 10-6km? (1km = 100000 cm)

Counting large numbers…• Easier when you use counting units:

Dozen (12)Ream (500)

Pair (2)Gross (144)

•Regardless of the object, the number that the units represents is always the same

•Atoms and molecules are extremely small, making it impossible actually count them (even in the smallest of samples)•Chemists need a unit for counting accurately the

# of atoms, molecules, or formula units; they use the mole•Mole (mol) = the SI base unit used to measure

the amount of a substance•1 mole of anything contains 6.02 x 1023

representative particles

1 mole of apples = 6.02 x 1023 apples

1 mole of diamonds = 6.02 x 1023 diamonds

1 mole of baseballs = 6.02 x 1023 baseballs

1 mole of carbon atoms = 6.02 x 1023 carbon atoms

The same applies to moles of compounds•How many molecules are in 1 mole of NH3?

6.02 x 1023 molecules of NH3

•How many molecules are in 1 mole of C9H8O4?6.02 x 1023

molecules of C9H8O4

What is Avogadro’s Number•6.02 X 1023 representative particles/mol•1 mol of any substance has 6.02 X 1023 representative

particles

What are representative particles?•Representative particles refers to the species present in a

substance: usually atoms, molecules, or formula units

Converting Particles to Moles• How many roses are in 3 ½ dozen roses?

USE CONVERSION FACTORS!!!3.5 dozen x 12 roses =42 roses

1 dozen conversion factor• How many pencils are in 6 gross?

6 gross x 144 pencils =864 pencils 1 gross conversion factor

12 roses = 1 dozen roses or

144 pencils = 1 gross pencils or

Conversion factor•A conversion factor is used to convert a measured quantity to a different unit of measure without changing the relative amount. To accomplish this, a ratio (fraction) is established that equals one (1)

Conversion factors for mole representative particles

or

Particles Moles Moles Particles

Converting Number of Particles to Mole

Conversion factor

Converting number of atoms to moles

Units you want are on top

These units cancel out

0.465

Converting Moles to Particles and Particles to Moles•How many moles contain 4.50 x 1024 atoms of zinc? 4.50 x 1024 atoms Zn x 1 mol zinc 6.02 x 1023 atoms Zn

7.48 mol Zn

SolveHow many moles of magnesium is 1.25 X 1023 atoms of magnesium?

Converting moles to number of particles

Conversion factor

Converting Moles to ParticlesHow many atoms can be found in 3.91 moles of xenon?

Converting Moles to Particles•How many particles of sucrose are in 3.50 moles of

sucrose?

3.50 mol sucrose x 6.02 x 1023 rep. part. 1mol

2.11 x 1024 particles of sucrose

SolveHow many cadmium atoms are there in 6.57 × 103 moles?X atoms of Cd= 6.57 x 103 mol ()X atoms of Cd = 3.96 x 1027 atoms of Cd

Solve• How many molecules are in 2.00 moles of H2O?Conv. Factor(s) Set-UpX molecules = 2.00 mol H2O ) X molecules = 1.20 x 1024 molecules H2O

Solve• How many moles are in 6.02 x 1023 atoms of carbon?Conv. Factor(s) Set-Up

• If you have 0.00812 mole of H2CO3, how many molecules do you have?

Conv. Factor(s) Set-Up

Challenge• How many atoms are in 2.00 moles of H2O? (Hint: H2O has 3 atoms)Conv. Factor(s) Set-Up