108
Formulas and Nomenclature
If cupric hydroxide reacts with perchloric acid, we write
Cu(OH) 2 + 1 HC1O 4 -^ Cu(ClO4) 2 + 2 H 2 O
And if aluminum hydroxide reacts with sulfuric acid, we write
2 A1(OH) 3 + 3 H 2 SO 4 -» AlzCSOJs + 6 H 2 O
In addition to showing which chemicals react and which are produced, the
chemical equation shows the relative numbers of molecules needed in the reaction. In the above reactions we had to use the proper numbers of acid molecules
and base molecules so that the salt that was formed would be electrically
neutral. In the third reaction, for example, the two Al
:i+ ions require three SC>5~
ions in order to have electroneutrality. Besides showing the correct chemical
formulas of all the reactants and products, ^balanced chemical equation always
abides by a principle of conservation, which might be stated as "atoms are
never created or destroyed in a chemical reaction." In other words, no matter
how drastically the atoms are rearranged in a chemical reaction, there must
always be the same number of each kind of atom in the collection of products
(the righthand side of the equation) as there is in the collection of reactants (the
lefthand side of the equation).
The rules for naming a salt depend on whether or not the acid from which it is
derived contains oxygen.
1. If the acid does not contain oxygen, the salt is named by replacing the
acid prefix hydro- by the name of the positive ion and changing the
suffix -ic to -ide; for example,
KBr
potassium bromide
Sb 2 S 3
antimonous sulfide or antimony(III) sulfide
Hg(CN) 2
mercuric cyanide or mercury(II) cyanide
2. If the acid does contain oxygen, the salt is named by giving the name of
the positive ion followed by the name of the acid, but changing the
suffix -ic to -ate or the suffix -ous to -ite; for example,
SrCO 3
strontium carbonate
Cu(ClO4) 2
cupric perchlorate or copper(II) perchlorate
(NH,t) 2 SO 3
ammonium sulfite
Co(BrO) 2
cobaltous hypobromite or cobalt(II) hypobromite
By changing the proportions in which some acids and bases are mixed, it is
possible to make salts in which only some of the replaceable hydrogen atoms
Formulas and Nomenclature
If cupric hydroxide reacts with perchloric acid, we write
Cu(OH) 2 + 1 HC1O 4 -^ Cu(ClO4) 2 + 2 H 2 O
And if aluminum hydroxide reacts with sulfuric acid, we write
2 A1(OH) 3 + 3 H 2 SO 4 -» AlzCSOJs + 6 H 2 O
In addition to showing which chemicals react and which are produced, the
chemical equation shows the relative numbers of molecules needed in the reaction. In the above reactions we had to use the proper numbers of acid molecules
and base molecules so that the salt that was formed would be electrically
neutral. In the third reaction, for example, the two Al
:i+ ions require three SC>5~
ions in order to have electroneutrality. Besides showing the correct chemical
formulas of all the reactants and products, ^balanced chemical equation always
abides by a principle of conservation, which might be stated as "atoms are
never created or destroyed in a chemical reaction." In other words, no matter
how drastically the atoms are rearranged in a chemical reaction, there must
always be the same number of each kind of atom in the collection of products
(the righthand side of the equation) as there is in the collection of reactants (the
lefthand side of the equation).
The rules for naming a salt depend on whether or not the acid from which it is
derived contains oxygen.
1. If the acid does not contain oxygen, the salt is named by replacing the
acid prefix hydro- by the name of the positive ion and changing the
suffix -ic to -ide; for example,
KBr
potassium bromide
Sb 2 S 3
antimonous sulfide or antimony(III) sulfide
Hg(CN) 2
mercuric cyanide or mercury(II) cyanide
2. If the acid does contain oxygen, the salt is named by giving the name of
the positive ion followed by the name of the acid, but changing the
suffix -ic to -ate or the suffix -ous to -ite; for example,
SrCO 3
strontium carbonate
Cu(ClO4) 2
cupric perchlorate or copper(II) perchlorate
(NH,t) 2 SO 3
ammonium sulfite
Co(BrO) 2
cobaltous hypobromite or cobalt(II) hypobromite
By changing the proportions in which some acids and bases are mixed, it is
possible to make salts in which only some of the replaceable hydrogen atoms