The Mole!

1. Also Known As… The single most terrifying, horrific, scariest chemistry concept of the modern world. The Mole!

2. What is a “Mole”? • The term “mole” means a specific amount of a substance in chemistry. The amount that the mole is equal to is 6.02x1023. • That is 602,000,000,000,000,000,000,000! We will use the scientific term since paper and ink costs us money and it’s not as hard on your hand. • Think of the “mole” like you would the words “dozen” and “pair” – they are words that mean a specific amount of something – 12 and 2 respectively. The mole just means a really big number and you could have a mole of anything – atoms, molecules, tennis balls, donkeys, pencils, etc… • 6.02x1023 is called Avogadro’s number – he was the guy that came up with it and realized its usefulness in the field chemistry. • The symbol for the mole is “mol” – Can you believe that?!?! • Poor letter “e”…poor lazy chemists.

3. What’s So Great About the Mole? • The mole is incredibly useful in carrying out reactions and calculations in chemistry because a mole of any element or compound will weigh the same as its mass (in grams) as per the masses on the periodic table. • What?!?!?! • Look at it this way…Think of holding a small amount of carbon in your hands…Well… 1 mole of C = 6.02x1023 atoms of C = 12.01g of C • It works the same way with molecules and/or compounds…Think of a small glass of water… 1 mole of H2O = 6.02x1023 = 18.02g of H2O (H2O = 1.01 + 1.01 + 16.00 = 18.02)

4. The Mole You Know • You learned (not “learnt”) in the chemistry unit of grade 10 science that you must balance all chemical equations. This was to satisfy the Law of Conservation of Mass – what goes in (reactants), must come out (products). • The coefficients you placed in the equation are the number of moles you need of each substance for the reaction to occur efficiently – both reactants used up – no leftover waste. • Example: The decomposition of water. 2H2O  2H2 + O2 • This means that 2 moles of water will break apart to give us 2 moles of hydrogen gas and 1 mole of oxygen gas.

5. Conversions: Particles & Moles • To convert between particles and moles you need to know that one mole is equal to 6.02x1023 particles. • The conversion factor here is 6.02x1023 particles/mol. • The following may help you… ÷ by 6.02x1023 particles/mol # of particles # of moles x by 6.02x1023 particles/mol

6. Also Known As… The “Massive” Return of the “Mole” People!!! Calculating Mass Using Moles

7. The molar mass of a substance is the mass (g) of one mole of the substance. Basically, it is the mass (in grams) of 6.02x1023 particles of a substance. Therefore, it would only make sense that the units for molar mass would be in grams/mole or g/mol. Molar Mass?

8. Converting Moles to Grams • To convert the number of moles you have into grams, or vice-versa, you need to know the molar mass of the substance you are dealing with. • To get the molar mass of a substance, you have to add up the masses of all the parts of that substance using the atomic masses from the periodic table. • For example: C2H6 = 2(12.01) + 6(1.01) = 30.08g/mol. • Now we can use this molar mass much like we used Avogadro’s number in the previous conversions between particles and moles. x by g/mol # of moles (mol) mass (g) ÷ by g/mol

9. The Big Picture • We can now…and take pride in this… • go from particles  moles – & vice versa. • and go from moles  mass – & vice versa. • So…We could go from particles to mass (or mass to particles) by using two steps. ÷ by 6.02x1023 particles/mol x by g/mol # of particles # of moles mass (g) x by 6.02x1023 particles/mol ÷ by g/mol

10. Now you are ready to conquer the world of the mole! Just make sure that your answers make sense and you have used the correct units in your answers. Now…Get to work! Holy Mole-y!

11. THE END!