1. Molecular Compounds
Section 9.3

2. Molecular Compounds
A prefix in the name of a binary molecular compound tells how many atoms of an element are present in each molecule of the compound.
Carbon monoxide CO
Carbon dioxide CO2

4. Writing Formulas for Binary Molecular Compounds
Use the prefixes in the name to tell you the subscript of each element in the formula. Then write the correct symbols for the two elements with the appropriate subscripts.
Silicon carbide SiC
Dinitrogen tetroxide N2O4

5. Naming Acids
Section 9.4

6. Naming Acids When the name of the anion (X) ends in
-ide, the acid name begins with the prefix hydro-. The stem of the anion has the suffix -ic and is followed by the word acid. Therefore, HCI(aq) (X =chloride) is named hydrochloric acid, H2S (aq) ( X = sulfide) is named hydrosulfuric acid.

7. When the anion name ends in
–ite, the acid name is the stem of the anion with the suffix -ous, followed by the word acid. Thus H2SO3 (aq) (X = sulfite) is named sulfurous acid.

8. 3. When the anion name ends in
-ate, the acid name is the stem of
the anion with the suffix -ic
followed by the word acid. Thus
HNO3 (aq) (X = nitrate) is named
nitric acid.

13. Laws Governing Formulas & Names
Section 9.5

14. Law of Definite Proportion
• In any sample of a chemical
compound the masses of the
elements are always in the same
proportion

15. Law of Definite Proportion
• This ratio does NOT change based
on the size of the sample or how it was formed
CO l2gC to l6gO
Ratio 3 to 4

16. • This is consistent with Dalton’s
Atomic Theory
• Atoms combine in simple whole
number ratios

17. • Dalton studied compounds that
contain same elements
• CO and CO2
• Both obey Law of Definite
Proportion

18. • CO 12g C to g O
•CO2 l2g C to g O
32g O (in CO2 per 12g C) = 2
16g O (in CO per 12g C) 1
• = 2: 1 ratio ****

19. Law of Multiple Proportions
Whenever two elements form more than one compound, the mass of one element compared to a fixed mass of another element is a ratio of small whole numbers