The Mole Concept

The Mole Concept

By Guzman

Counting Atoms

A Chemist's Dozen

1 mole = 6.022 x 10²³ particles

• 1 dozen = 12 objects

• 1 score = 20 objects

​

• The MOLE

  • 1 mole equals the amount of substance that contains 6.0221421 x 10²³ particles

Avogadro's Number & Molar Mass

​The mass of one mole of a substance is called Molar Mass (MM)

• Units are g​/mol

• In an element 1 mole is equal to its Atomic Mass​

Molar Mass

1 mole of atoms of any element will have a mass equal to its relative Atomic Mass

• Its shown in grams​

​Once Again

​1 Mol = 23 grams

2 Mol =

3 Mol =

​Examples

How many grams are in 2 mol of Carbon (C)?

1. Look for the element

2. Look at the atomic mass

3. multiply the mol they are asking for​

Multiple Choice

How many particles are found in a mole?

• $$6.022\ x\ 10^{23}$$  

• $$6.022\ x\ 1023$$  

• $$6022\ x\ 10^{23}$$  

• $$6022\ x\ 1023$$  

Multiple Choice

What are the units used for Molar Mass

• grams

• mols

• g/mol

• mol/g

Multiple Choice

How many grams are in 1 mole of Mg?

• 12 grams

• 24 grams

• 36 grams

• 6.022 x 10²³ grams

Multiple Choice

How many grams are in 3 mol of carbon?

• 6 grams

• 12 grams

• 18 grams

• 36 grams

Multiple Choice

How many grams are in 5 mol of lithium

• 3 grams

• 15 grams

• 35 grams

• 7 grams

Multiple Choice

How many grams are in 10 mol of fluorine?

• 19 grams

• 190 grams

• 90 grams

• 9 grams

Formula Weight

​Its the sum of all the atomic weights in a formula.

to find the formula weight of a compound:

1. fin the number of atoms of each element present in the compound

2. multiply the number of atoms by their respective weight

3. add the atomic weights of all the elements present.

Example: H₂O

1. H₂O contains 2 atoms of Hydrogen and 1 atom of Oxygen​

   ​

2. Hydrogen: 2 x 1.0080 = 2.016

Oxygen: 1 x 16 = 16

​

3. 2.016 + 16 = 18.016

Multiple Choice

what are the units used for Molecular Weight?

• amu

• grams

• g/mol

• mol

Multiple Choice

Find the formula weight of Sugar - C₁₂H₂₂O₁₁

• 198.176 amu

• 342.308 amu

• 144.132 amu

• 29.019

Multiple Choice

Find the molecular weight of Vitamin A - C₂₀H₃₀O

• 286.46 amu

• 240.22 amu

• 29.019 amu

• 129.46 amu

Multiple Choice

Find the molecular weight of carbon monoxide - CO

• 16 amu

• 12.011 amu

• 28.011 amu

• 29.019 amu

Multiple Choice

Find the molecular weight of acetic acid - CH₃COOH

• 24.022 amu

• 31.035 amu

• 29.019 amu

• 60.054 amu

Putting these together

​Gram Formula Mass

• ​This is the combination of formula weight and mol

• Moles are used not only to describe elements, but compounds as well.

• When asked about the weight of 1 mol of a compound, you will follow the same steps as finding the molecular weight of your compound.​

• its units are g/mol​

​

​Example

Determine the gram formula mass of each compound: KMnO₄

(this is asking for the mass of one mol of your compound)

​

K = 1 x 39.098 = 39.098

Mn = 1 x 54.938 = 54.938

O = ​4 x 16 = 64

= 158.036​ g/mol

Multiple Choice

What are the units used for Gram Formula Mass?

• amu

• grams

• mol

• g/mol

Multiple Choice

Determine the gram formula mass of KCl

• 74.548 amu

• 35.45 amu

• 74.548 g/mol

• 35.45 g/mol

Multiple Choice

Determine the gram formula mass of H₂SO₄

• 98.076 mol

• 98.076 g/mol

• 98.076 g

• 98.076 amu