section 2.4—defining, naming & writing acids & bases we need to know how acids and bases...
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Section 2.4—Defining, Naming & Writing Acids & Bases
We need to know how acids and bases behave when talking about ant-acids!
Acids – Arrhenius DefinitionA compound that has a H+ cation that it
can donate to water to produce the hydronium ion (H3O+1)
H
OH
water
H+1
H
OH
H +1
By this definition, if an acid is to give a H+1 to water, then all acids will have hydrogen as the cation (first element written).
hydronium ion
These compounds :Start with “H” (more than 1 “H” is OK, too).Have only 2 elements in total (One of them is
hydrogen the other is NOT oxygen.)Examples: HCl H2S
To name these compounds:Use “hydro____ic acid”Fill in the blank with the anion’s name without
the last syllable
Naming Non-oxygen Acids
These compounds have:Start with “H” (more than 1 “H” is OK, too).Contain a polyatomic ion that has oxygen in it.
To name these compounds:Use “___ic acid” for “-ate” anions; the blank is
filled in with the polyatomic ions name without the suffix.
Use “___ous acid” for “-ite” anions; the blank is filled in with the polyatomic ions name without the suffix.
Naming Oxygen Acids
Examples: HNO2 is . . . HNO3 is . . .
Example #2
Hydrogen cation
Sulfite ion
It’s an acid
“-ite” ionUse “___ous” acid
H2SO3
Sulfurous acid
Let’s Practice
hydroiodic acid
carbonic acid
acetic acid
phosphorous acid
Example:Write the name for the following
compounds
HI
H2CO3
HC2H3O2
H3PO3
To write these formulas:The cation is H+1
Write the anion and chargeBalance the charges by adding the appropriate
subscript to the hydrogen cation
“Hydro-” acids
To write these formulas:The cation is H+1
If it is an “-ic” acid, the anion is the “-ate” polyatomic ion
If it is an “-ous” acid, the anion is the “-ite” polyatomic ion
Add subscript to the hydrogen cation to balance charges
NON “Hydro-” acids
Let’s Practice
Example:Write the
formula for the following acids
Phosphoric acid
Hydroiodic acid
Acetic acid
Perchloric acid
Phosphoric acid
Hydroiodic acid
Acetic acid
Perchloric acid
Let’s Practice
H3PO4
HI
HC2H3O2
HClO4
Example:Write the
formula for the following acids
Bases
Objective:•Define and distinguish between acids & bases•Explain and use nomenclature rules for naming and writing formulas for bases
Bases – Arrhenius Definition
Bases produce the hydroxide ion in water
MOST bases will be ionic compounds with the OH-1 anion. (Ex. NaOH or Ca(OH)2)
MOST IMPORTANT EXCEPTION is NH3 (ammonia).NH3 + H2O NH4
+1 + OH-1
HO-1
Hydroxide Ion
Most bases are just ionic compounds with “hydroxide” as their anion
The most common exception to this is ammonia. NH3 is a base even though it doesn’t contain “-OH” as the anion.
Naming Bases
Let’s Practice
Example:Write the formula or
name for each
Ca(OH)2
KOH
Sr(OH)2
Copper (II) hydroxide
Magnesium hydroxide