Naming and Writing Formulas for
Acids and Bases
Chapter 9
Chemical Names and Formulas
Section 4
Vocabulary
• Acid
– A compound that produces hydrogen ions (H+) in
solution.
• Base
– A compound that produces hydroxide ions (OH-)
in solution.
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State Standards
• 4.6
• Name and write the chemical formula for
simple ionic and molecular compounds,
including those that contain the polyatomic
ions: ammonium, carbonate, hydroxide,
nitrate, phosphate, and sulfate
3
Key Questions
• How do you determine the name and formula
of an acid?
• How do you determine the name and formula
of a base?
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Names and Formulas of Acids
• You can consider the acid to consist of an
anion combined with as many hydrogen ions
as needed to make the molecule electrically
neutral.
• The chemical formulas of acids are in the
general form HnX.
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Three Rules for Naming Acids
1. When the name of the anion ends in –ide,
the acid name begins with the prefix hydro-.
The stem of the anion has the suffix –ic and
is followed by the word acid.
– HCl (X is chloride) is hydrochloric acid.
2. When the anion names ends in –ite, the acid
name is the stem of the anion with the
suffix –ous, followed by the word acid.
– H2SO3 (X is sulfite) is named sulfurous acid
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Three Rules for Naming Acids
3. When the anion name ends in –ate, the acid
name is the stem of the anion with the
suffix -ic, followed by the word acid.
– HNO3 (X is nitrate) is named nitric acid.
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Writing Formula for Acids
• To write the formula for an acid, use the rule
for writing the name of the acid in reverse.
Then balance the ionic charges just as you
would for any ionic compound.
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Name and Formula of Bases
• A base is generally an ionic compound that
produces hydroxide (OH-) when dissolved in
water.
• Bases are named in the same way as other
ionic compounds- the name of the cation is
followed by the name of the anion.
– NaOH
– Sodium Hydroxide
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Name and Formula of Bases
• To write the formula for a base, first write the
symbol for the metal cation followed by the
formula for the hydroxide ion. Then, balance
the ionic charges just as you would for any
ionic compound.
– Aluminum hydroxide
– Al3+
– OH– Al(OH)3
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Summary
• If the anion name ends in –ide, the acid name
begins with the prefix hydro-. The stem of the
anion has the suffix –ic and is followed by the
word acid. If the anion name ends in –ite, the
acid name is the stem of the anion with the
suffic –ous, followed by the word acid. If the
anion name ends in –ate, the acid name is the
stem of the anion with the suffix –ic, followed
by the word acid. To write the formula for an
acid, use the rule for writing the name of the
acid in reverse.
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Summary
• Bases are named like other ionic compounds.
To write the formula for a base, write the
symbol for the metal cation followed by that
of the hydroxide ion. Then, balance the ionic
charges.
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