Unit 6 Chemical Naming and Moles Chapter 9-10

Naming Ions Positive Ions, cations, simply retain their name. Na +  Sodium Ion Mg 2+  Magnesium Ion

Naming Ions Negative Ions, anions, change ending of element to –ide Cl -  Chloride Ion Br -  Bromide Ion

Unique Anions Names N 3-  Nitride Ion O 2-  Oxide Ion S 2-  Sulfide Ion P 3-  Phosphide Ion

Polyatomic Ions Selected polyatomic ions are on Table E in the Reference Tables. Polyatomic ions keep their names in most chemical names

Naming Systems Ionic System Stock System (Roman Numerals) Binary Covalent System (Prefixes)

When to use ionic system First element is a metal NaCl More than 2 elements, meaning polyatomic ion is involved NH 4 Cl

Naming Ionic Compounds Name positive ion first, then negative ion. NaCl  Sodium chloride Mg(OH) 2  Magnesium hydroxide

Problem Name these 2 compounds, using the ionic system CuClCopper Chloride CuCl 2 Copper Chloride Different compounds need to have different names

Stock System Use when the metal element has more than one positive oxidation number

Stock System We must indicate which charge the metal ion has, using Roman Numerals CuClCuCl 2 Cu +1 Cu +2 Copper(I)ChlorideCopper(II)Chloride Roman Numeral is the charge of the metal ion

Roman Numerals Cation Charge Roman Numeral +1I +2II +3III +4IV +5V +6VI +7VII +8VIII

Example Fe 3 (PO 4 ) 2 Iron(II) Phosphate PO 4 Fe +2

Binary Covalent Compounds Use when compound is 2 nonmetals Including metalloids Use a prefix system to indicate the number of atoms for each element Second element ends in -ide

Prefixes Number of atomsPrefix 1mono- 2di- 3tri- 4tetra- 5penta- 6hexa- 7hepta- 8octa-

Example N 2 Cl 3 Dinitrogen Trichloride

Exceptions When there is only one atom of the first element, do not use mono- prefix. CO 2 Carbon dioxide OF 2 Oxygen difluoride

Exceptions When an element starts with a vowel, drop any o or a at the end of a prefix CO Carbon Monooxide Carbon Monoxide P 2 O 5 Diphosphorus Pentaoxide Diphosphorus Pentoxide

Words representing Numbers Dozen12 Baker’s Dozen13 Gross144 Ream500 Mole6.02 x 10 23

Avogadro’s Number 6.02 x Number of representative particles in a mole 1 mol He = 6.02 x atoms 1 mol H 2 = 6.02 x molecules

Practice 2 mol H 2 = x molecules 2 mol H 2 = x atoms 2 mol H 2 O = x atoms 2 mol C 6 H 12 O 6 = x O atoms

Mole-Mass relationship 1 mole of any element equals the atomic mass in grams 1 mol Carbon = 12.01g Carbon 1 mol Iron = 55.8g Iron

Gram Formula Mass Mass of the formula in g/mol Simply add the atomic masses of each element in the formula together H 2 O = = 18 g/mol Also known as gram atomic mass, gram molecular mass, molar mass

Rounding Round most masses to the nearest whole gram Except: Copper, Cu  63.5 Chlorine, Cl  35.5

Practice KNO 3 = (3) = 101 g/mol C 6 H 14 = 12(6) + 1(14) = 86 g/mol CuSO 4 = (4) = g/mol

Mole - Mass Conversion Example: 96 g of Oxygen gas = ? mol

Practice How many moles are there in 506g of ethanol, C 2 H 6 O? What is the mass of 8 moles of CCl 4 ? 1232g CCl 4 11 mol C 2 H 6 O

Molar Volume At STP, 1 mol of any gas occupies 22.4L of space Examples: 2 mol of He occupies how much space at STP? 11.2L will have how much H 2 gas at STP? 44.8L 0.5 mol

Mole Road Map

Review How many moles are in 584g of SF 6 ? How many grams are in 6 mol of HCl? X = 584g 146 g/mol = 4 mol 6 mol = X 36.5 g/mol = 219 g

Percent Composition

Example H 2 O H 11.1% H O 88.9% O

Another Example NH 3 N 82.4% N H 17.6% H

Percent Composition What is the percent composition of oxygen in H 2 SO 3 ? 58.5%

Percent Composition What is the percent composition of aluminum in Al 2 (SO 4 ) 3 ? 15.8%

Percent Composition What is the percent composition of nitrogen in NH 4 NO 3 ? 35%

Hydrates Compounds that have a specific number of water molecules attached Dot means plus (+) gfm = (18) = 249.5g/mol CuSO 4 ·5H 2 O

Formulas Molecular Formula Shows the total number of atoms in a molecule H 2 O Structural Formula Shows the total number of atoms in a molecule, and how the bonds are arranged OH H

Empirical Formula Simplest Whole-Number ratio of atoms in a compound Examples CO 2 P 4 O 10 P 2 O 5 C 6 H 12 O 6 CH 2 O

Empirical Formula Molecular Formula is a multiple of the Empirical Formula

Examples Compound that has 4 carbon atoms for every 8 hydrogen atoms C 4 H 8 CH 2 Compound that has 6 carbon atoms for every 18 hydrogen atoms C 6 H 18 CH 3

Empirical Formula A molecular formula has an empirical formula of CH 2 and a molecular mass of 28 g/mol. A molecular formula has an empirical formula of CH 2 and a molecular mass of 42 g/mol. C2H4C2H4 C3H6C3H6