1. Molar Mass and Moles

2. What is a Mole?
Because chemical reactions often involve large numbers of particles, chemists use a counting unit called the mole to measure amounts of a substance

3. Molar mass cont.
A mole (mol) is an amount of a substance that contains approximately 6.02x1023 particles (atoms) of that substance A mole of iron is 6.02x1023 atoms of iron

4. Molar Mass
The mass of one mole of a substance is called its molar mass For an element, the molar mass is the same as the atomic mass, only expressed as grams

5. Molar Mass
The atomic mass of Carbon is g

6. Finding The Molar Mass
For a compound, you would add up the molar masses of each element present in the compound Carbon Dioxide (CO2) = 12.0g + (16.0g x 2) Carbon dioxide has a molar mass of…..

7. Find the molar mass! Sodium (Na) Cobalt (Co) Sodium Chloride (NaCl)
Magnesium Chloride (MgCl2)

8. Mole – Mass Conversions
Once you know the molar mass of a substance, you can convert the moles of that substance into mass OR the mass of the substance into moles

9. Mole – Mass conversions
The molar mass of CO2 is 44.0g, which means that one mole of CO2 has a mass of 44.0g Suppose you had 55.0g of CO2, but you wanted to know how many moles of CO2 that you had (55.0g x 1 mol CO2)/44.0g = 1.25 mol CO2

10. Convert the molar mass
You have 125 g of H2O. You want to know how many moles you have
What is the molar mass of H2O?
How many moles do you have if you have 125g of H2O?

11. Conversions
From mass to mole: Mass of sample/molar mass = # of moles From mole to mass: Molar mass X # of moles From # of atoms to moles # atoms / 6.02x1023 From moles to # of atoms # of moles (6.02x1023)