1. The Mole

2. Atomic Mass Relative weight - the atomic mass unit (amu) is used to describe the mass of an atom relative to a carbon-12 isotope. 1mole of any element makes the relative weight equal to the gram weight. Elementrelative weightatomic weight H1 amu1 g/mol O16 amu16 g/mol

3. The Mole A mole is a quantity - 1 mole of any substance contains 6.02 x 10 23 particles –Example: –1 dozen = 12 things –1 pair = 2 things –1 ream = 500 things Avogadros’s number = 6.02x10 23

4. Molar Mass (MM) The mass in grams of 1 mole of a molecule is the molar mass. The mass in grams of an ionic compound is called the formula mass. A formula unit is an ionic compound.

5. Molar or Formula Mass Calculations Example: 1. What is the formula mass of CuO? Cu = 63.55 g/molO = 16.00 g/mol CuO = 63.55 + 16.00 = 79.55 g/mol 2. What is the molar mass of H 2 O? H = 1.01 g/mol, O = 16.00 g/mol H 2 O = (1.01 x 2) + 16.00 = 18.02 g/mol

6. Molar Mass Formula mass and molar mass are calculated the same way. Formula mass refers to ionic compounds and molar mass refers to molecules. The formula gives the mole ratio of each atom in the compound. Example: 1 mole of H 2 O = 2 mole of hydrogen atoms and 1 mole of oxygen atoms

7. Mole Conversions Balanced chemical equations give the mole ratio of reactants and products. –2H 2 + O 2  2H 2 O : 2 moles of hydrogen reacts with 1 mole of oxygen to make 2 moles of water. To find grams or molecules/formula units you must convert using moles.

8. Converting Between Moles and grams 1.How many grams is 2 moles of water?  Use the molar mass to convert between moles and grams: 2 moles H 2 O x 18.02 g = 36.04 g mole 2.How many moles are in 5.0 grams of H 2 O? 5 g H 2 O x mole =.28 moles 18.02 g

9. Converting between Molecules and Moles 1.How many molecules are in 2 moles of water?  Use Avogadro's number to convert from moles to molecules. 2 moles H 2 O x 6.02 x 10 23 molecules = mole 1.20 x 10 24 molecules