Nomenclature
Acids and Bases
Recap
• Last class…
– Reviewed what a molecular compound is
– Learned how to name molecular compounds
• Prefixes!
– Learned how to derive the formula for molecular
compounds when given the name
Learning Goals
• We are learning to
– Identify acids and bases from
their chemical formulas
– Name acids and bases given
their chemical formulas
Identifying Acids
You can identify an acid from its name or
chemical formula:
• Name: ends in ‘acid’
• chemical formula:
– starts with H (hydrogen)
ie: HCl – Hydrochloric Acid
OR
– ends with CO2H (carboxyl ion)
ie: CH3CO2H – Acetic Acid or vinegar
Naming Binary Acids
A. Formula HnX where X = halogen, S or P
1. Prefix “hydro.”
2. To the name of the non-metallic element, add
the suffix “ic” and the word “acid.
•
•
•
HF – hydrofluoric acid
HCl – hydrochloric acid
H2S – hydrosulphuric acid
Naming Oxy Acids
B. Formula HnX where X = polyatomic ion
1. Name the element in the polyatomic ion that is
not oxygen.
2. If the ion ends in -ate, add the suffix “-ic” then
acid. If the ion ends in –ite, add the suffix “-ous”
then acid.
3. Write (aq) after the formula
•
•
•
H2SO2(aq) – sulphurous acid
H3PO4(aq) – phosphoric acid
H2CrO4(aq) – chromic acid
Identifying Bases
• You can identify a base from its name or
chemical formula:
• Name: begins with name of a metallic ion,
ends with ‘hydroxide.’
• Chemical formula:
– Starts with a metallic ion or ammonium ion NH4+
AND
– Ends with OH or HCO3 or CO3
• Hydroxyl, hydrogen carbonate, carbonate
Naming Bases
• XOH where X = metal or ammonium
– Name as you would any ionic compound, metal
first then hydroxide
• XHCO3 (metal + hydrogen carbonate)
XCO3 (metal + carbonate)
– Name as you would any other ionic compound,
metal first then polyatomic ion
Acid or Base?
Identify each of the following as acidic or basic and
name/give the formula based the rules outlined in
today’s lesson…
1.
2.
3.
4.
5.
6.
HI
KOH
Mg(OH)2
NaCl
H2CO3
LiOH
7. nitric acid
8. calcium hydroxide
9. hydrobromic acid
10.ammonium hydroxide
11.phosphoric acid
12.hydrofluoric acid
Hydrates
• Hydrates: Compounds contain H2O in their
structure
• Different from (aq), the H2O is part of the
molecule
• The H2O can usually be removed if heated.
Naming Hydrates
• A dot separates water:
– CuSO4•5H2O - copper(II) sulfate pentahydrate.
• A prefix indicates the # of H2O groups
– Na2SO4•10H2O
– NiSO4•6H2O
– sodium carbonate monohydrate
– barium chloride dihydrate
Homework
Complete the
acid/base
Worksheet