SAT Subject Test Chemistry

PART 2

REVIEW OF MAJOR TOPICS

CHAPTER 4

Chemical Formulas

NAMES AND FORMULAS OF COMMON ACIDS AND BASES

The definition of an acid and a base is expanded later in a first-year chemistry course. For now, common acids are aqueous solutions containing excess hydrogen ions, H+. Common bases are aqueous solutions containing excess hydroxide ions, OH.

A binary acid is named by placing the prefix hydro- in front of the stem or full name of the nonmetallic element, and adding the ending -ic. Examples are hydrochloric acid (HCl) and hydrosulfuric acid (H2S).

ternary compound consists of three elements, usually an element and a polyatomic ion. To name the compound, you merely name each component in the order of positive first and negative second.

Ternary acids usually contain hydrogen, a nonmetal, and oxygen. Because the amount of oxygen often varies, the name of the most common form of the acid in the series consists of merely the stem of the nonmetal with the ending -ic. The acid containing one less atom of oxygen than the most common acid is designated by the ending -ous. The name of the acid containing one more atom of oxygen than the most common acid has the prefix per- and the ending -ic ; that of the acid containing one less atom of oxygen than the -ous acid has the prefix hypo- and the ending -ous. This is evident in Table 7 with the acids containing H, Cl, and O.

You can remember the names of the common acids and their salts by learning the following simple rules:

TIP 

Learn these rules.

When the name of the ternary acid has the prefix hypo- or per-, that prefix is retained in the name of the salt (hypochlorous acid = sodium hypochlorite).

The names and formulas of some comon acids and bases are listed in Table 7.