1. Mullis1 Naming Compounds Binary Ionic Compounds Cation (+ charge ) is listed first. Name of cation is the chemical name. –For many transition metals, the ion is distinguished by the addition of a roman numeral after the chemical name. –Find charge of the anion and choose appropriate roman numeral to balance the charge. Name of the anion ends in –ide. Examples: Al 2 O 3 aluminum oxide CuBr 2 copper(II) bromide

2. Mullis2 Writing Formulas for Ionic Compounds The positive ion comes FIRST. Write the charge of each ion over each symbol to help you decide the subscripts. The total charges must add to 0. The criss-cross method will accomplish this: Do not write the sign of the charge or “1” Use subscripts to indicate how many ions are needed to make the compound. Use parentheses to for polyatomics if there are more than one. Mg 2+ ClMgCl 2

3. Mullis3 Naming Molecular Compounds Binary Molecular Compounds If more than one atom, name the first element with a numerical prefix. Name the second element with a numerical prefix and a suffix –ide. For prefixes, drop o or a if the element name begins with a vowel. (Examples are monoxide and pentoxide.) Examples: N 2 O 4 dinitrogen tetroxide OF 2 oxygen difluoride

4. Mullis4 Numerical Prefixes NumberPrefix 1mono- 2di- 3tri- 4tetra- 5penta- 6hexa- 7hepta- 8octa- 9nona- 10deca-

5. Mullis5 Oxidation Numbers Used to indicate the general distribution of electrons among the bonded atoms in molecular compounds or polyatomic ions. Analogous to charges in ionic compounds. An oxidation number is assigned to each element. Assign the ones you know 1 st. Find the others based on the numbers it takes to make the charge equal to the charge of the ion or compound. (A compound has a charge of zero.)

6. Mullis6 Oxidation Numbers: Rules 1.Pure element = 0 2.F = -1 3.O = -2 (except in peroxides and bonds with halogens) 4.H = +1 (except in bonds with metals) 5.The more electronegative element = same (-) charge as its anion 6.The less electonegative element = same (+) charge as its cation 7.The sum of a compound or polyatomic ion’s oxidation numbers is equal to its charge.

7. Mullis7 Relationship between mass, moles and molecules in a compound Mass (g) Amount (moles) # molecules or Formula units X molar mass (__g__ mole) X 6.022 x 10 23 (units mole) Grams moles = moles gram moles units = units or molecules mole moles grams = grams mole

8. Mullis8 Molar Mass Example What is the molar mass of K 2 SO 4 ? 2 mol K x 39.10 g K = 78.20 g K 1 mol K 1 mol S x 32.10 g S = 32.07 g S 1 mol S 4 mol O x 16.00 g O = 64.00 g O 1 mol O molar mass K 2 SO 4 = 174.27 g/mol How many moles of each element are present in this compound? 2 mol K, 1 mol S, 4 mol O

9. Mullis9 Molar mass Molar mass of a substance = mass in grams of one mole of the substance. A compound’s molar mass is NUMERICALLY equal to its formula mass. 2 mol H x 1.01 g H = 2.02 g H 1 mol H 1 mol O x 16.00 g O = 16.00 g O 1 mol Omolar mass H 2 O = 18.02 g/mol Formula mass H 2 O = 18.02 amu Molar mass H 2 O = 18.02 g/mol

10. Mullis10 What is the molar mass of C 6 H 12 O 6 ? 6 mol C x 12.01 g C = 72.06 g C 1 mol C 12 mol H x 1.01 g H = 12.12 g H 1 mol H 6 mol O x 16.00 g O = 96.00 g O 1 mol O molar mass C 6 H 12 O 6 = 180.18 g/mol How many moles of each element are present in this compound? 6 mol C, 12 mol H, 6 mol O

11. Mullis11 Converting to grams from moles How many moles of glucose are in 4.15x10 -3 g C 6 H 12 O 6 ? 4.15x10 -3 g x 1 mol C 6 H 12 O 6 = 2.30 x 10 -5 mol C 6 H 12 O 6 180.18 g How many molecules of glucose are in 4.15x10 -3 g C 6 H 12 O 6 ? 2.30 x 10 -5 mol C 6 H 12 O 6 x 6.022 x 10 23 molecules = 1 mol (2.30 x 6.022)( 10 (-5+23) ) = 13.90 x 10 –18 molecules = 1.39 x 10 –19 molecules

12. Mullis12 What is the mass in grams of 6.25 moles copper (II) nitrate? Cu 2+ NO 3 - : formula is Cu(NO 3 ) 2 Find molar mass of Cu(NO 3 ) 2 first. 1 mol Cu x 63.55 g Cu = 63.55 g Cu 1 mol Cu 2 mol N x 14.01 g N = 28.02 g N 1 mol N 6 mol O x 16.00 g O = 96.00 g O 1 mol O molar mass Cu(NO 3 ) 2 = 187.57 g/mol Now find mass in grams of 6.25 moles: 6.25 moles x 187.57 g = 1172 gAns. 1170 g Cu(NO 3 ) 2 1 mol

13. Mullis13 Percentage Composition % Composition is the % by mass of each element in a compound. Find the percentage composition of sodium chloride. Na + Cl - : formula is NaCl 1 mol Na x 22.99 g Na = 22.99 g Na 1 mol Na 1 mol Cl x 35.45 g Cl = 35.45 g Cl 1 mol Cl molar mass NaCl = 58.44 g/mol 22.99 g Na x 100 = 39.34 % Na 58.44 g NaCl 35.45 g Cl x 100 = 60.66 % Cl 58.44 g NaCl

14. Mullis14 Find the percentage composition of sodium nitrate. Na + NO 3 - : formula is NaNO 3 1 mol Na x 22.99 g Na = 22.99 g Na 1 mol Na 1 mol N x 14.01 g N = 14.01 g N 1 mol N 3 mol O x 16.00 g O = 48.00 g O 1 mol O molar mass NaNO 3 = 85.00 g/mol 22.99 g Na x 100 = 27.05 % Na 85.00 g NaNO 3 14.01 g N x 100 = 16.48 % N 85.00 g NaNO 3 48.00 g O x 100 = 56.47% O 85.00 g NaNO 3

15. Mullis15 Percentage Composition Why mass instead of moles? Isn’t 2/3 of the water molecule hydrogen? Moles indicate the amounts of each atom needed to make the molecule stable from an electron standpoint. 2.02 g H x 100 = 11.21 % H 18.02 g H 2 O HH O