1. RR: How many ways can you count to 100?

2. Do you know how to count? In chemistry, the unit that helps us count is the mole (mol). The mole represents 6.022 x 10 23 pieces of something. 6.022 x 10 23 = 602,200,000,000,000,000,000,000 called Avogadro’s number In chemistry, our pieces are atoms, particles, ions, molecules, etc. We can express the mole mathematically as a conversion factor – a mathematical ratio used to express a relationship between different units.

3. Avogadro’s Number and the Mole

4. RR: How many atoms are in 1.0 mole of carbon?

5. Known (what you have) Unknown (what you need) Relationship (conversion factor) Shown Work Answer

6. RR: How many molecules of KBr are in 5 moles of KBr? Known (what you have) Unknown (what you need) Relationship (conversion factor) Shown Work Answer

7. RR: What units do we use to measure mass in chemistry?

8. Mass and the Mole Elements on the periodic table are measured in atomic mass units, but most of the time, chemists use grams instead. Each element’s mass is located on the periodic table. We can find the molar mass (mass per mole) of each element by dividing the mass of the element by the moles of the element. For a single mole of an element, the mass is the same as the mass on the periodic table. Example: What is Carbon’s molar mass ?

9. Molar Mass of a Molecule or Compound If we know the number of moles of each element, we can find the total mass of a molecule by adding together the molar masses of each element. Note, moles ≠ atoms

10. How can we determine the mass of 1 mole of glucose, C 6 H 12 O 6 ? First, break the molecule into pieces. Next, determine the mass for each piece (element) by using the molar mass. Total the masses of the different pieces.