1. Take your periodic table out

2. What is atomic mass of Carbon Point where you can find it in the periodic table! 6 is atomic number not atomic mass Atomic mass= mass of 1 mol

3. Calculating Formula Mass /molecular weight Write down how you calculate the formula mass of carbon dioxide, CO 2. 12.01 g + 2(16.00 g) =  One mole of CO 2 (6.02 x 10 23 molecules) has a mass of 44.01 grams

4. We use Unit factors = ratio of 1:1 to convert 1 mole= 6.022 X 10 ^ 23 atoms 1 mole= atomic mass if an atom( like C) Molecular weight if a molecule (CO2)

5. Why are Ratio of 1 significant? 3.09X10^23 atoms= ?mol Math rule: If we multiply something on one side we have to do it on the other side Ratio of 1 so we don’t need to worry about that rule

6. Calculations with Moles: Converting moles to grams How many grams of lithium are in 3.50 moles of lithium? 3.5moles-> ? g lithium 3.50 mol Li = g Li 1 mol Li 6.94 g Li 24.3 What unit factor are we using here? 1 mole= 6.94g Li

7. Calculations with Moles: Using Avogadro’s Number How many atoms of lithium are in 3.50 moles of lithium? 3.50 mol = atoms 1 mol 6.02 x 10 23 atoms 2.11 x 10 24 What unit factor are we using here? 1 mole= 6.022 X 10 ^ 23 atoms

8. Calculations with Moles: Converting grams to moles How many moles of lithium are in 18.2 grams of lithium? 18.2 g Li = mol Li 6.94 g Li 1 mol Li 2.62 What unit factor are we using here? 1 mole= 6.94g Li

9. Calculations with Moles: Using Avogadro’s Number How many atoms of lithium are in 18.2 g of lithium? 18.2 g Li = atoms Li 1 mol Li 6.022 x 10 23 atoms Li 1.58 x 10 24 6.94 g Li1 mol Li (18.2)(6.022 x 10 23 )/6.94 What unit factors are we using here? 6.941 g 1 =mole 1 mole= 6.022 X 10 ^ 23 atoms