The The MoleMole

CA StandardsCA Standards

The MoleThe Mole

1 dozen =1 gross =

1 ream =

1 mole =

12

144

500

6.02 x 1023

There are There are exactlyexactly 12 grams of 12 grams of carbon-12 in one mole of carbon-12 in one mole of carbon-12.carbon-12.

Avogadro’s NumberAvogadro’s Number6.02 x 1023 is called “Avogadro’s Number” in honor of the Italian chemist Amadeo Avogadro (1776-1855).

Amadeo Avogadro

I didn’t discover it. Its just named after

me!

I didn’t discover it. Its just named after

me!

Calculating Formula MassCalculating Formula MassCalculate the formula mass of carbon Calculate the formula mass of carbon dioxide, COdioxide, CO22..

12.01 g + 2(16.00 g) =12.01 g + 2(16.00 g) =44.01 44.01 gg

One mole of CO2 (6.02 x 1023 molecules) has a mass of 44.01 grams

Mole Mole RelationshiRelationshi

psps

Mole Mole

Atomsor

molecules

Atomsor

molecules

Liters Liters

Grams Grams

6.02 x

6.02 x 1010 2323

6.02 x

6.02 x 1010 2323

Ato

mic

Ato

mic

Mass

Mass

Ato

mic

Ato

mic

Mass

Mass

22. 4

L

22. 4

L

22. 4

L

22. 4

L22.4 L

Calculations with Moles:Calculations with Moles:Converting moles to gramsConverting moles to grams

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

3.50 mol Li= g Li

1 mol Li

6.94 g Li 45.145.1

Calculations with Moles:Calculations with Moles:Converting grams to molesConverting grams to moles

How many moles of lithium are in 18.2 grams of lithium?

18.2 g Li= mol Li

6.94 g Li

1 mol Li2.622.62

Calculations with Moles:Calculations with Moles:Using Avogadro’s NumberUsing Avogadro’s Number

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

3.50 mol

= atoms1 mol

6.02 x 1023 atoms 2.07 x 102.07 x 102424

Calculations with Moles:Calculations with Moles:Using Avogadro’s NumberUsing Avogadro’s Number

How many atoms of lithium are in 18.2 g of lithium?

18.2 g Li

= atoms Li

1 mol Li 6.022 x 1023 atoms Li

1.58 x 1024

6.94 g Li 1 mol Li

(18.2)(6.022 x 1023)/6.94

Standard Molar VolumeStandard Molar Volume

Equal volumes of all gases at the same temperature and pressure contain the same number of molecules.

- Amedeo Avogadro

Equal volumes of all gases at the same temperature and pressure contain the same number of molecules.

- Amedeo Avogadro

At STP (Standard Temperature and Pressure):

1 mole of a gas occupies 22.4 liters of volume

At STP (Standard Temperature and Pressure):

1 mole of a gas occupies 22.4 liters of volume

Calculations with Moles:Calculations with Moles:Using Standard Molar VolumeUsing Standard Molar Volume

How many moles of hydrogen are in 100 L of hydrogen at STP?

100 L = mol

22.4 L

1 mol4.644.64

Calculations with Moles:Calculations with Moles:Using Standard Molar VolumeUsing Standard Molar Volume

How many liters are occupied by 3 moles of oxygen gas at STP?

3 mol = L

1 mol

22.4 L67.267.2