Unit 6 Chemical Naming and Moles Chapter 9-10
Naming Ions
Negative Ions, anions, change ending of element to –ide Cl- Chloride Ion Br- Bromide Ion
Polyatomic Ions
Selected polyatomic ions are on Table E in the Reference Tables.
Polyatomic ions keep their names in most chemical names
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 Mg(OH)2 Magnesium hydroxide
Problem Name these 2 compounds, using the
ionic system
CuCl Copper Chloride
CuCl2 Copper Chloride
Different compounds need to have different names
Stock System
We must indicate which charge the metal ion has, using Roman Numerals CuCl CuCl2 Cu+1 Cu+2
Copper(I)ChlorideCopper(II)Chloride
Roman Numeral is the charge of the metal ion
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
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
Avogadro’s Number
6.02 x 1023
Number of representative particles in a mole
1 mol He = 6.02 x 1023 atoms 1 mol H2 = 6.02 x 1023 molecules
Practice
2 mol H2 = 12.04 x 1023 molecules
2 mol H2 = 24.08 x 1023 atoms
2 mol H2O = 36.12 x 1023 atoms
2 mol C6H12O6 = 72.24 x 1023 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
H2O = 1 + 1 + 16 = 18 g/mol Also known as gram atomic mass,
gram molecular mass, molar mass
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
Practice
How many moles are there in 506g of ethanol, C2H6O?
What is the mass of 8 moles of CCl4?
molg
gx
/46
506
molg
xmol
/1548 1232g CCl4
11 mol C2H6O
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
Review
How many moles are in 584g of SF6?
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
Hydrates
Compounds that have a specific number of water molecules attached
Dot means plus (+) gfm = 159.5 + 5(18) = 249.5g/mol
CuSO4·5H2O
Formulas
Molecular 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
H
Empirical Formula
Simplest Whole-Number ratio of atoms in a compound
Examples CO2
P4O10 P2O5
C6H12O6 CH2O
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