2. The Mole

3. Standards

4. 1 dozen = 1 gross = 1 ream = 1 mole = 12 144 500 6.02 x 10 23 There are exactly 12 grams of carbon-12 in one mole of carbon-12.

5. Avogadro’s Number 6.02 x 10 23 is called “Avogadro’s Number” in honor of the Italian chemist Amadeo Avogadro (1776-1855). Amadeo Avogadro I didn’t discover it. Its just named after me!

6. Calculating Formula Mass Calculate the formula mass of carbon dioxide, CO 2. 12.01 g + 2(16.00 g) = 44.01 g  One mole of CO 2 (6.02 x 10 23 molecules) has a mass of 44.01 grams

7. Mole Relationships The Mole Atoms or molecules Atoms or molecules Liters of gas Grams 6.02 x 10 23 AtomicMassAtomicMass 22. 4 L 22.4 L We will re-visit this later in the year Gram-molecular mass or molar mass Avogadro’s number

8. Calculations with Moles: Converting moles to grams How many grams of lithium are in 3.50 moles of lithium? 3.50 mol Li = g Li 1 mol Li 6.9 g Li 24.2 Convert using the factor-label method Always use “1” mole of ____ in conversion

9. 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 6.9 g Li 1 mol Li 2.64 You can convert from grams to moles again be sure to use “1” mole of ____ in conversion.

10. 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 of Li 6.02 x 10 23 atoms 2.07 x 10 24 You can convert from moles to atoms again be sure to use “1” mole of ____ in conversion.

11. 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 6.02 x 10 23 atoms Li 1.59 x 10 24 6.9 g Li1 mol Li (18.2)(6.022 x 10 23 )/6.9 You can convert from grams to atoms but you have to convert to moles along the way.