Chemical Naming and Moles Chapter 9-10 Unit 6 Chemical Naming and Moles Chapter 9-10

Naming Ions Positive Ions, cations, simply retain their name. Na+  Sodium Ion Mg2+  Magnesium Ion

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

Unique Anions Names N3-  Nitride Ion O2-  Oxide Ion S2-  Sulfide Ion P3-  Phosphide Ion

Stock System Used when the metal has more than one positive oxidation number Use a roman numeral to indicate the charge of the ion

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

Stock System Examples Fe+2  Iron(II) Cu+  Copper(I) Mn+7  Manganese(VII) Au+3  Gold(III) Cr+6  Chromium(VI) Pb+4  Lead(IV)

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 Binary Covalent System (Prefixes) 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 NH4Cl

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

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 atoms Prefix 1 mono- 2 di- 3 tri- 4 tetra- 5 penta- 6 hexa- 7 hepta- 8 octa-

Example N2Cl3 Dinitrogen Trichloride

Exceptions When there is only one atom of the first element, do not use mono- prefix. CO2 Carbon dioxide OF2 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 P2O5 Diphosphorus Pentaoxide Diphosphorus Pentoxide

Words representing Numbers Dozen 12 Baker’s Dozen 13 Gross 144 Ream 500 Mole 6.02 x 1023

Avogadro’s Number 6.02 x 1023 Number of representative particles in a mole Mole number 1 mol He = 6.02 x 1023 atoms 1 mol H2 = 6.02 x 1023 molecules 1 mol H2 = 12.04 x 1023 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 H2O = 1 + 1 + 16 = 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 KNO3 = 39 + 14 + 16(3) = 101 g/mol C6H14 = 12(6) + 1(14) = 86 g/mol CuSO4 = 63.5 + 32 + 16(4) = 159.5 g/mol

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

Practice How many moles are there in 506g of ethanol, C2H6O? What is the mass of 8 moles of CCl4? 11 mol C2H6O 1232g CCl4

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 H2 gas at STP? 44.8L 0.5 mol

Mole Road Map

Review How many moles are in 584g of SF6? How many grams are in 6 mol of HCl? 584g X = = 4 mol 146 g/mol X 6 mol = = 219 g 36.5 g/mol

Percent Composition

Example H2O H 11.1% H O 88.9% O

Another Example NH3 N H 82.4% N 17.6% H

Percent Composition What is the percent composition of oxygen in H2SO3? 58.5%

Percent Composition What is the percent composition of aluminum in Al2(SO4)3? 15.8%

Percent Composition What is the percent composition of nitrogen in NH4NO3? 35%

Hydrates Compounds that have a specific number of water molecules attached Dot means plus (+) gfm = 159.5 + 5(18) = 249.5g/mol CuSO4·5H2O

O H Formulas Molecular Formula Structural Formula Shows the total number of atoms in a molecule H2O Structural Formula Shows the total number of atoms in a molecule, and how the bonds are arranged O H

Empirical Formula Simplest Whole-Number ratio of atoms in a compound Examples CO2 P4O10 P2O5 C6H12O6 CH2O

Empirical Formula Molecular Formula is a multiple of the Empirical Formula

Examples Compound that has 4 carbon atoms for every 8 hydrogen atoms C4H8 CH2 Compound that has 6 carbon atoms for every 18 hydrogen atoms C6H18 CH3

Empirical Formula A molecular formula has an empirical formula of CH2 and a molecular mass of 28 g/mol. A molecular formula has an empirical formula of CH2 and a molecular mass of 42 g/mol. C2H4 C3H6