1. mole (symbolized mol) = 6.02 x 10 23 particles (602,000,000,000,000,000,000,000) Avogadro’s Number (N A ) molar mass – mass (usually in grams) of one mole of a substance

2. The mass of one mole of an element is the atomic mass of that element expressed in grams. 1 mol of Cu = 63.5 g 1 mol of S = 32.1 g

3. The molar mass of a compound is the sum of the molar masses of its component atoms. (Sum of atomic masses expressed in grams.) 1 mol NaClNa23.0 Cl35.5 58.5 g 1 mol H 2 O 2 H 2(1.0) O16.0 18.0 g

4. Practice Problem Calculate the molar mass of KNO 3 K39.1 N14.0 3O48.0(3 x 16.0) 101.1 g / mol

5. Mole to gram conversions: Mass of 1.50 moles of Cu? 1.50 mole Cu x 63.5 g Cu = 95.3 g Cu 1 mole Cu 1 mole Cu = 63.5 g Cu

6. Practice Problem What is the mass of 2.50 mol of helium, He? 2.50 mole He x 4.0 g He =10. g He 1 mole He 1 mole He = 4.0 gHe

7. Practice Problem What is the mass of 0.150 mol of Na 2 SO 4 ? 2Na46.0(2 x 23.0) S32.1 4 O 64.0(4 x 16.0) 142.1 g / mol 0.150 mol Na 2 SO 4 x 142.1 g = 21.3 g Na 2 SO 4 1 mol

8. Gram to mole conversions: How many moles in 26.0 g NaOH? 26.0 g NaOH x 1 mole = 0.650 mol NaOH 40.0 g 1 mole NaOH = 40.0 g NaOH Na 23.0 O 16.0 H 1.0 40.0

9. Practice Problem How many moles are there in 500.0 g AlCl 3 ? Al 27.0 3Cl106.5(3 x 35.5) 133.5 g / mol 500.0 g AlCl 3 x 1 mole = 3.745 mol AlCl 3 133.5 g

10. Moles to atoms or molecules: How many atoms are in 0.82 moles of Mg? 0.82 mol Mg x 6.02 x 10 23 atoms 1 mole = 4.9 x 10 23 atoms Mg

11. Practice Problem How many atoms are present in 0.025 mol of Fe? 0.025 mol Fe x 6.02 x 10 23 atoms 1 mole = 1.5 x 10 22 atoms Fe