Name ___________________________________ Date ______________________ Class ______________________
Chapter 9 – Chemical Names and Formulas
Acids and Bases
An acid is a compound that produces H+ ions in an aqueous (water) solution. A base is a compound that produces OHions in an aqueous solution.
Naming Acids
Acids not containing a polyatomic ion (or oxygen) are named by using hydro- plus the root of the anion plus –ic plus
acid. Acids containing oxygen are named by using the polyatomic root plus –ic if the original polyatomic name contained
–ate or plus –ous if the original root was –ite. If there is sulfur in the polyatomic –ur is added before the –ic or –ous. If
there is a phosphorus in the polyatomic –or is added before the –ic or –ous. These are summarized below.
1.
2.
3.
4.
5.
If no oxygen: hydro + anion root + ic + acid (example – HCl is hydrochloric acid).
If oxygen present: polyatomic root + ic (replacing –ate ending) + acid (example HClO3 – chloric acid).
If oxygen present: polyatomic root + ous (replacing –ite ending) + acid (example HClO2 – chlorous acid).
If sulfur present: polyatomic root + ur + ic/ous + acid (example H2SO4 – sulfuric acid).
If phosphorus present: polyatomic root +or + ic/ous + acid (example H3PO4 – phosphoric acid).
**Work the following problems – name the following acids.
Formula
HBrO
H2CO3
HCl
H2S
HNO3
H2SO4
HC2H3O2
H3PO3
HF
HSCN
Compound Name
Writing Formulas for Acids
To write the formula for an acid look at the name. Reverse the process and change the endings to find out
which root anion or polyatomic ion you are dealing with. Next, balance the negative charges with hydrogen.
Example 1: periodic acid…root polyatomic would be periodate or IO41- so balance that with hydrogen to get HIO4.
Example 2: thiosulfuric acid…root polyatomic would bethiosulfate or S2O32- so balance that with hydrogen to get H2S2O3.
**Work the following problems – write the formula for the following acids.
Compound Name
Formula
Compound Name
hydrosulfuric acid
nitric acid
bromous acid
sulfuric acid
thiosulfuric acid
Formula
chromic acid
hydroiodic acid
nitrous acid
perchloric acid
dichromic acid
Naming Bases
A base is composed of a metal and an OH- ion. You name the metal and then the OH- with hydroxide.
Ammonia, NH3 is a base. When ammonia is put into water it forms ammonium, NH4 and gives off OH- ions.
NH3 + H2O → NH4+ + OH-.
Examples:
NaOH is sodium hydroxide
Fe(OH)3 is iron (III) hydroxide
**Work the following problems – name the following bases.
Formula
KOH
Fe(OH)2
Al(OH)3
Mg(OH)2
LiOH
Compound Name
Writing Formulas for Bases
To write the formula for bases simply write the formula like you would for an ionic compound. Write the
formula for the metal ion, using Roman numerals where needed, then the formula for hydroxide. Balance the formula
and you’re done.
**Work the following problems – write the formula for the following bases.
Compound Name
zinc hydroxide
iron (III) hydroxide
chromium (II) hydroxide
beryllium hydroxide
calcium hydroxide
Formula
Compound Name
silver hydroxide
nickel (II) hydroxide
sodium hydroxide
aluminum hydroxide
copper (III) hydroxide
Formula