1. chemistry

2. Naming and Writing Formulas for Molecular Compounds
9.3
One milligram of gold is worth only about one cent, but one kilogram of gold is worth approximately $12,500. The correct prefix ( milli- or kilo-) makes quite a difference! Prefixes are important in chemistry, too. The prefixes in the name of a binary molecular compound tell you its composition.

3. Naming Binary Molecular Compounds
9.3
Naming Binary Molecular Compounds
Naming Binary Molecular Compounds
What does a prefix in the name of a binary molecular compound tell you about the compound’s composition?

4. Naming Binary Molecular Compounds
9.3
Naming Binary Molecular Compounds
Carbon and oxygen combine to form carbon monoxide (CO) and carbon dioxide (CO2), but these two invisible gases are very different.
Carbon monoxide is an invisible, gaseous compound of carbon and oxygen. It is a toxic product of incomplete burning, such as occurs in automobile engines and faulty furnaces.

5. Naming Binary Molecular Compounds
9.3
Naming Binary Molecular Compounds
Sitting in a room with small amounts of CO2 in the air would not present any problems. If the same amount of CO were in the room, you could die of asphyxiation. A naming system that distinguishes between these two compounds is needed.
Carbon monoxide is an invisible, gaseous compound of carbon and oxygen. It is a toxic product of incomplete burning, such as occurs in automobile engines and faulty furnaces.

6. Naming Binary Molecular Compounds
9.3
Naming Binary 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.

7. Naming Binary Molecular Compounds
9.3
Naming Binary Molecular Compounds
Some guidelines for naming binary molecular compounds:
Name the elements in the order listed in the formula.
Use prefixes to indicate the number of each kind of atom.

8. Naming Binary Molecular Compounds
9.3
Naming Binary Molecular Compounds
Omit the prefix mono- when the formula contains only one atom of the first element in the name.
The suffix of the name of the second element is -ide.

9. Writing Formulas for Binary Molecular Compounds
9.3
Writing Formulas for Binary Molecular Compounds
Writing Formulas for Binary Molecular Compounds
How do you write the formula for a binary molecular compound?

10. Writing Formulas for Binary Molecular Compounds
9.3
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.

11. Writing Formulas for Binary Molecular Compounds
9.3
Writing Formulas for Binary Molecular Compounds
Silicon carbide is a hard material like diamond. The name silicon carbide has no prefixes, so the subscripts of silicon and carbon must be one. Thus, the formula for silicon carbide is SiC.
A grinding wheel made of silicon carbide (SiC) can shape even the toughest materials. Inferring What causes the sparks?

12. 9.3 Section Quiz.
Assess students’ understanding of the concepts in Section 9.3.

13. 9.3 Section Quiz.
1. Which of the following compounds is named INCORRECTLY?
CS2, carbon disulfide
BCl3, boron trichloride
IF7, iodine heptafluoride
PCl5, phosphorus hexachloride

14. 9.3 Section Quiz.
2. Which of the following molecular compounds is named INCORRECTLY?
SbCl3, antimony trichloride
C2O5, dicarbon pentoxide
CF4, carbon tetrafluoride
H3As, hydrogen arsenide

15. 9.3 Section Quiz.
3. The correct formula for tetraphosphorus trisulfide is
P3S4
S3P4
P4S3
S4P3

16. END OF SHOW