Lesson 11
Lesson Glossary
chemical formula
a standard scientific symbol by which each element or compound is known
chemical name
a standard scientific name by which each element or compound is known
common name
a name given to a chemical before the international naming system was created
Formulas for Common Compounds
When you get together with family or friends, you communicate by using the same language. If
you each use a different language, you will not be able to understand one another. Scientists from
all over the world need to be able to communicate, even though they may speak different
languages. As a result, scientists have devised a common language to deal with chemicals and
chemical reactions.
The common language scientists have devised is the chemical symbols and names for the
elements and compounds. In previous science courses, you studied the symbols for some
common compounds. Here is one such common compound.
1. Use the symbol for water to answer the following.
a. What is the symbol for hydrogen?
b. What is the symbol for oxygen?
c. How many hydrogen atoms are there in this compound?
d. How many oxygen atoms are there in this compound?
e. Which subscript indicates the number of oxygen atoms?
f. What does the subscript (l) mean?
Now, it's time to get a little more background information on chemical names of elements and
compounds and the chemical formulas that describe their chemical composition.
Turn to page 50 of the textbook and read "Chemical Names and Formulas."
2. Where can you find a list of the names and symbols of all the chemical elements known to
scientists?
3. How is each symbol for a chemical element written?
4. A chemical formula gives the _______________ of a compound.
5. a. The word equation for the reaction of sulfur and zinc is
Write the chemical equation for this reaction.
b. How many atoms of sulfur are present in the reactants?
c. What rule was used to name ZnS?
6. Read "Did You Know?" on page 50 of the textbook. Which subscript is used to indicate a
substance dissolved in water?
Chemicals are used by people in many industries. Not all these people are scientists. Therefore,
many chemical compounds are often identified by common names. Some common names you
may already be familiar with, like antifreeze for ethylene glycol, baking soda for sodium
bicarbonate, and table salt for sodium chloride.
Read "Common Names" on page 51 of the textbook. Study Table 3.1 carefully; it lists the
common names, chemical names, and chemical formulas of a number of substances.
7. Why are common names used for many substances?
8. Write the common name for each of the following chemical names.
a. sodium bicarbonate
b. sodium hydroxide
c. methane
9. Write the chemical formula for each of the following common chemicals.
a. alcohol
b. chalk
c. quartz
10. List the elements in each of the following chemical formulas.
a. CaCO3(s)
b. SiO 2(s)
c. KCl