HAHSMS. KNICK

Avogadro, The Mole, and Grams

The MoleThe Mole

The amount of substance that contains as many particles as there are atoms in exactly 12 g of carbon.

We can think of the mole is a counting unit for chemists. Examples:

1 dozen =12 1 ream of paper = 500 sheets

Avogadro’s NumberAvogadro’s Number

Is the number of particles in exactly one mole of a pure substance.

6.02 x 1023 is called “Avogadro’s Number” in honor of the Italian chemist Amadeo Avogadro (1776-1855).

I didn’t discover it. Its just named after me!

Avogadro’s Number (con’t)Avogadro’s Number (con’t)

There is 602000000000000000000000 atoms in 1 mole of a substance

THAT’S A GIGANTIC NUMBER!!!!!!!!!

Molar Mass

Is the mass of 1 mole of a per substance

Has units of grams per mole (g/mol)

Equaled to the atomic mass of the element or compound.

Molar Mass of a Compound

Add up all the masses of each type of atom in the compound.

Example: Molar Mass of Ca(OH)2Ca: 1 x 40 = 40 O: 2 x 16 = 32 The molar mass is the

H: 2 x 1 = 2 sum (40 + 32 + 2) which is equaled to 74 g/mol

Molar Mass

Is the mass of 1 mole of a per substance

Has units of grams per mole (g/mol)

Equaled to the atomic mass of the element or compound.

Calculations:Calculations:Converting moles to gramsConverting moles to grams

Given # of mole X g (look at periodic table)= g of 1 mole

How many grams of lithium are in 3.50 moles of lithium?

3.50 mole X 6.941 g = 24.29 g Li 1 mol

Calculations:Calculations:Converting grams to molesConverting grams to moles

Given # of g X 1 mol = mol of

g (look at periodic table)How many moles of lithium are in

18.2 grams of lithium?18.2 g X 1 mol Li = 2.622 mol Li 6.941 g

Calculations:Calculations:Converting Moles to Converting Moles to

ParticlesParticlesGiven # of mol x 6.02 x 1023 part= atoms 1 molHow many atoms/particles/molecules of

lithium are in 3.50 moles of lithium?3.50 mole X 6.02 x 1023 = 2.11 x 1024 atoms of Li 1 mol

Calculations:Calculations:Converting Particles to Converting Particles to

MolesMolesGiven # of particles x 1 mole = mol 6.02 x 1023

How many moles of lithium are there in 1.2044 x1024 particles of Li?

1.2044 x 1024 part x 1 mole = 2.0 mol Li 6.02 x 1023 part

Calculations:Calculations:Converting grams to Converting grams to

particlesparticlesGiven # of grams x 1 mol x 6.022 x 1023=

particles ? g 1 mol How many atoms/particles/molecules of

lithium are in 18.2 g of lithium?18.2 g x 1 mol x 6.022 x 1023 = 1.58 x 1024 particle

Li 6.941g 1 mol

Calculations:Calculations:Converting particles to Converting particles to

gramsgramsGiven # of particles x 1 mol x ? g =

g 6.022 x 1023 1 molHow many grams are there in 8.02 x 1025

particles of lithium?