6. The Stock System of Nomenclature CuCl 2 Name of cation + Roman numeral indicating charge Name of anion copper(II) chloride Oxyanions – polyatomic ions containing oxygen.
8. P 4 O 10 Prefix needed if there is more than one atom + Name of less – electronegative element Prefix indicated by the number of atoms contributed by more-electronegative element Root name of more-electronegative element + ide + tetraphosphorus decoxide
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13. Using Oxidation Numbers for Formulas and Names The Stock System is based on oxidation numbers and can be used as an alternative way to the prefix system. Formula Prefix System Stock System PCl 3 phosphorus trichloride phosphorus (III) chloride PCl 5 phosphorus pentachloride phosphorus (V) chloride
14. Using Chemical Formulas Formula Masses Finding the formula mass for H 2 O Step 1: Find the average atomic mass for hydrogen and oxygen Step 2: Use the conversion table to change atoms to atomic mass units (amu) Average atomic mass of H: 1.01 amu Average atomic mass of O: 16.00 amu
15. 2 H atoms H atoms 1.01 amu = 2.02 amu 1 O atoms O atoms 16.00 amu = 16.00 amu Average mass of H 2 O molecule = 18.02 amu Step 3: Add the atomic mass units to find the average mass
16. Molar Mass Finding the molar mass for H 2 O Step 1: Find the molar mass for hydrogen and oxygen Step 2: Use the conversion table to change moles to grams. Molar mass of H: 1.01 g/mol Molar mass of O: 16.00 g/mol
17. 2 mol H 1 mol 1.01 g = 2.02 g 1 mol O 1 mol 16.00 g = 16.00 g Average mass of H 2 O molecule = 18.02 g Step 3: Add the masses to find the total mass
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