chapter 7.1: the mole and molar conversions

Chapter 7.1: The Mole and Molar Conversions

Objectives: (1) To define the mole. (2) To perform molar conversions.

Do you know the following?

1 pair = 1 dozen = 1 score = 1 gross = 1 ream = 1 mole (mol) =

1 pair = 2 1 dozen = 12 1 score = 20 1 gross = 144 1 ream = 500 1 mole (mol) = 6.02 x 1023

The MOLE

A mole of a substance is 6.02x1023 representative particles of that substance.

This number is called Avogadro’s number.

The symbol for mole is mol.

Representative Particle

The term representative particle refers to the species present in a substance (i.e. atoms or molecules) Example: Ca is one atom Example: CO2 is one molecule (i.e.

molecular compound)

Representative Particle

What is the representative particle of Ca?

What is the representative particle of H2O?

What is the representative particle of CO?

What is the representative particle of Zn?

Representative Particle What is the representative particle of Ca?

atom

What is the representative particle of H2O? molecule

What is the representative particle of CO? molecule

What is the representative particle of Zn?

atom

The Concept of the Mole

One mole of donuts contains 6.02 x 1023 donuts One mole of H2O contains 6.02 x 1023

molecules One mole of nails contains 6.02 x 1023 nails One mole of Fe contains 6.02 x 1023 atoms One mole of dogs contains 6.02 x 1023 dogs One mole of electrons contains 6.02 x 1023

electrons

Get the idea?

Just How Big is a Mole?

Mole Facts

6.02 X 1023 Watermelon Seeds: Would be found inside a melon slightly larger than the moon.

6.02 X 1023 Donut Holes: Would cover the earth and be 5 miles (8 km) deep.

6.02 X 1023 Pennies: Would make at least 7 stacks that would reach the moon.

6.02 X 1023 Grains of Sand: Would be more than all of the sand on Miami Beach.

Molar Conversions

How many eggs are in 15 dozen?

Molar Conversions

How many eggs are in 15 dozen?

15 dozen 12 eggs

1 dozen180 eggs

Molar Conversions Roadmap

Atoms or Molecules

MOLES Grams

Divide by 6.022x1023

Multiply by 6.022x1023

Multiply by molar mass

Divide by molar mass

Solving Molar Conversion Problems

Step 1: Figure out how many parts your calculation will have using the diagram.

Step 2: Make a T-chart and enter number/units in the appropriate spaces.

Step 3: Fill in your conversion factor. Step 4: Cancel units. Step 5: Multiply numbers on top and

divide by numbers on the bottom.

Example #1

How many moles are in 3.01 x 1023 molecules of sulfur dioxide?

Example #1

How many moles are in 3.01 x 1023

molecules of sulfur dioxide?

3.01 x 1023

molecules SO2

6.02 x 1023

molecules SO2

1 mol SO2

Example #1

How many moles are in 3.01 x 1023

molecules of sulfur dioxide?

3.01 x 1023

molecules SO2

6.02 x 1023

molecules SO2

1 mol SO2

0.50 mol SO2

Example #2

How many moles of carbon dioxide are present in 3.161 x 1023 molecules of carbon dioxide?

Example #2 How many moles of carbon dioxide are

present in 3.161 x 1023 molecules of carbon dioxide?

3.161 x 1023

molecules CO2

6.02 x 1023

molecules CO2

1 mol CO2

Example #2 How many moles of carbon dioxide are

present in 3.161 x 1023 molecules of carbon dioxide?

3.161 x 1023

molecules CO2

6.02 x 1023

molecules CO2

1 mol CO2

0.53 mol CO2

Example #3

How many moles of carbon are in 2.44 x 1023 atoms of carbon?

Example #3

How many moles of carbon are in 2.44 x 1023 atoms of carbon?

2.44 x 1023

atoms C

6.02 x 1023

atoms C

1 mol C

Example #3

How many moles of carbon are in 2.44 x 1023 atoms of carbon?

2.44 x 1023

atoms C

6.02 x 1023

atoms C

1 mol C

0.41 mol C

Example #4

How many molecules are in 0.125 moles of carbon dioxide?

Example #4

How many molecules are in 0.125 moles of carbon dioxide?

0.125 moles CO2

1 mole CO2

6.02 x 1023

molecules CO2

Example #4

How many molecules are in 0.125 moles of carbon dioxide?

0.125 moles CO2

1 mole CO2

6.02 x 1023

molecules CO2

7.53 x 1022 molecules CO2

Example #5

How many atoms are in 2.50 moles of Au?

Example #5

How many atoms are in 2.50 moles of Au?

2.50

moles Au

1 mole Au

6.02 x 1023

atoms Au

Example #5

How many atoms are in 2.50 moles of Au?

2.50

moles Au

1 mole Au

6.02 x 1023

atoms Au

1.51 x 1024

atoms Au