2.8 Classifying Inorganic Compounds

(Section 8.1 pg 201-208)

• So far, we’ve been generally looking at inorganic compounds– compounds that don’t contain a high % of carbon by weight.

• There are 2 main types of inorganic compounds (Fig.2 p.202):

• Inorganic molecular compounds are molecules formed with 2 non-metals (but no C or very little C!).

• Common examples: water (H2O), ammonia (NH3), CO2

(counts as low % of C).

• Inorganic ionic compoundsare divided into three categories: Acids, Bases and Salts. – Acids = any substance that releases H+ ions in solution

(they usually start with an H-)– Bases = any substance that releases OH- ions in solution.

(They usually end in -OH)– Salts = any ionic substance that does not have an H+ or

OH- ion.

• Chemical indicators are commonly used in labs to test for acids/bases (Table 2 p.203 & Data Pages

• Please note H2O is basically composed of one H+ ion and one OH- ion (Fig.4 p.204).

• Please read the section ‘Acidity’ on p.204 of your text – good info.

• Acidity is a measure of the relative amounts of H+ and OH- ions in solution (Table 4 p.205) – the higher the number of H+ ions in solution the more acidic it is (opposite is true for basic solutions).

• Check out the pH scale in your Data Pages – gives examples of the pH of common solutions.

• The pH scale is used to measure acidity (see Fig.6&8 p.205-6). On this scale acids have a pH 0-7, pH = 7 is neutral, and pH 7-14 is basic.

• The pH scale is logarithmic, meaning that every 1 point on the scale represents 10 times more or less acidity (see Table 5 p.206).

• There are a separate set of rules for naming acids – please see the flow chart handout (Fig.9 p.207).

• To name a base or a salt we follow the rules used for naming ionic compounds (Table 7 p.208).