2.8 Classifying Inorganic Compounds

1. 2.8 Classifying Inorganic Compounds (Section 8.1 pg 201-208)

2. 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):

3. 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).

4. 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.

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

6. 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.

7. 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.

8. 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).

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

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