1. Chemical Formulas & The Mole CCl 2 F 2 = 1 molecule of freon with 1 carbon atom, 2 chlorine atoms, & 2 fluorine atoms So a dozen molecules of freon would have 1 dozen carbon atoms, 2 dozen chlorine atoms & 2 dozen fluorine atoms What would 1 mole of freon contain? If you had 5.5 moles of freon, how many moles of fluorine would there be?

2. Try It 1.How many moles of Al +3 ions are in 1.25 moles of Al 2 O 3 ? 2.Determine the number of moles of chlorine ions in 2.50 mol ZnCl 2. 3.Determine the number of moles of sulfate ions present in 3.00 mol iron (III) sulfate.

3. Molar Mass of Compounds Mass of a mole of any compound = masses of everything in it Molar mass of freon = 1.000 mol C x 12.011 g C/mol = 12.011 g 2.000 mol Cl x 35.453 g Cl/mol = 70.906 g 2.000 mol F x 18.998 g F/mol = 37.996 g Molar Mass of CCl 2 F 2 = 120.91 g/mol

4. Try It Find the molar mass of CaCl 2 Sr(NO 3 ) 2 C 2 H 5 OH What’s the mass of 2.50 mol C 2 H 5 OH? How many moles are in 500 g of Sr(NO 3 ) 2 ?

5. Answers Find the molar mass of CaCl 2 = 110.98 g/mol Sr(NO 3 ) 2 = 211.63 g/mol C 2 H 5 OH = 46.07 g/mol What’s the mass of 2.50 mol C 2 H 5 OH? 2.5 mol x 46.07 g / 1 mol = 115 g How many moles are in 500 g of Sr(NO 3 ) 2 ? 500 g x 1 mol / 211.63g = 2.36 moles