1. HAHS MS. KNICK Avogadro, The Mole, and Grams

2. The Mole The amount of substance that contains as many particles as there are atoms in exactly 12 g of carbon. We can think of the mole is a counting unit for chemists.  Examples:  1 dozen =12  1 ream of paper = 500 sheets

3. Avogadro’s Number Is the number of particles in exactly one mole of a pure substance. 6.02 x 10 23 is called “Avogadro’s Number” in honor of the Italian chemist Amadeo Avogadro (1776-1855). I didn’t discover it. Its just named after me!

4. Avogadro’s Number (con’t) There is 602000000000000000000000 atoms in 1 mole of a substance THAT’S A GIGANTIC NUMBER!!!!!!!!!

5. Molar Mass Is the mass of 1 mole of a per substance Has units of grams per mole (g/mol) Equaled to the atomic mass of the element or compound.

6. Molar Mass of a Compound Add up all the masses of each type of atom in the compound. Example: Molar Mass of Ca(OH)2 Ca: 1 x 40 = 40 O: 2 x 16 = 32 The molar mass is the H: 2 x 1 = 2 sum (40 + 32 + 2) which is equaled to 74 g/mol

7. Molar Mass Is the mass of 1 mole of a per substance Has units of grams per mole (g/mol) Equaled to the atomic mass of the element or compound.

8. Calculations: Converting moles to grams Given # of mole X g (look at periodic table) = g of 1 mole How many grams of lithium are in 3.50 moles of lithium? 3.50 mole X 6.941 g = 24.29 g Li 1 mol

9. Calculations: Converting grams to moles Given # of g X 1 mol = mol of g (look at periodic table) How many moles of lithium are in 18.2 grams of lithium? 18.2 g X 1 mol Li = 2.622 mol Li 6.941 g

10. Calculations: Converting Moles to Particles Given # of mol x 6.02 x 10 23 part = atoms 1 mol How many atoms/particles/molecules of lithium are in 3.50 moles of lithium? 3.50 mole X 6.02 x 10 23 = 2.11 x 10 24 atoms of Li 1 mol

11. Calculations: Converting Particles to Moles Given # of particles x 1 mole = mol 6.02 x 10 23 How many moles of lithium are there in 1.2044 x10 24 particles of Li? 1.2044 x 10 24 part x 1 mole = 2.0 mol Li 6.02 x 10 23 part

12. Calculations: Converting grams to particles Given # of grams x 1 mol x 6.022 x 10 23 = particles ? g 1 mol How many atoms/particles/molecules of lithium are in 18.2 g of lithium? 18.2 g x 1 mol x 6.022 x 10 23 = 1.58 x 10 24 particle Li 6.941g 1 mol

13. Calculations: Converting particles to grams Given # of particles x 1 mol x ? g = g 6.022 x 10 23 1 mol How many grams are there in 8.02 x 10 25 particles of lithium?