LESSON 6
A New Language
Chemical Names and Symbols
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Think About It
There are two bottles on a shelf in a chemistry lab. Each contains a substance that
resembles diamonds. Bottle 1 is labeled C(s), and Bottle 2 is labeled ZrO2(s). Does
either bottle contain diamonds? Do both bottles contain diamonds?
What do chemical names and symbols tell you about matter
To answer this question, you will explore

The Language of Chemistry

Names and Symbols

Physical Form
Exploring the Topic
The Language of Chemistry
Some chemical names are used in daily language, such as aluminum and iron, which
cookware and machinery are made of, and ammonia, which is used for cleaning. Other
names are used mainly by chemists, such as sodium chloride for salt and calcium
carbonate for chalk.
In the illustration, the symbol C is used when the word carbon appears in the name, and the symbol O
appears when the word oxygen or oxide is in the name.
CONSUMER
CONNECTION
Neon is the gas used in neon signs. The gas is colorless but glows a bright orange red
when an electric current is run through it. Neon gas is put into glass tubes that have
been bent and shaped to create colorful signs.
Names and Symbols
Elements are the building materials of all matter. In total there are about 118 known
elements. A few are shown here.
Here are some things you might notice. The chemical symbols for the elements
consist of one or two letters. The first letter is always capitalized. If there is a second
letter, it is lowercase. An element can be a solid, liquid, or gas. Some elements are
metals, some are not. Sometimes the symbol for an element is an abbreviation for its
name. Other times, the symbol comes from another source, such as a word in another
language. For example, the symbol for iron is Fe from the Latin word ferrum, and the
symbol for gold is Au from the Latin word aurum.
Elements combine in specific ratios to form compounds. A compound is represented
by a chemical formula. For example, sodium chloride, or table salt, is NaCl, which
tells you that salt is made of the elements sodium, Na, and chlorine, Cl, in a 1:1 ratio.
The chemical formula for carbon dioxide is CO2. The subscript number “2” in the
formula indicates that the elements carbon and oxygen are combined in a 1:2 ratio. (If
the subscript is 1, you normally don’t write it.)
Chemical formula for carbon dioxide
Compounds can be very different in appearance and behavior from the elements that
they are composed of. For example, sodium is a shiny metal and chlorine is a gas. They
are very different from sodium chloride, table salt.
BIG IDEA
All matter is made up of elements or compounds, or mixtures of these.
These minerals contain copper, Cu. Notice that not one of them is copper colored.
Copper oxide, Cu2O(s)
Copper sulfate, CuSO4(s)
Copper sulfide, CuS(s)
Copper carbonate hydroxide, Cu2(CO3)(OH)2(s)
Physical Form
Elements and compounds can exist as solids, liquids, or gases, and this is represented
by using (s), (l), or (g) after the chemical formula. These are called the phases of
matter. For example, water in the gas phase is written as H2O(g). Water is written as
H2O(l) when it is in the liquid phase and H2O(s) when it is in the solid phase as ice.
There is another symbol for physical form, the symbol (aq) for aqueous. A substance is
aqueous when it dissolves and forms a clear mixture with water. Many familiar liquids
are actually aqueous solutions, such as grape juice, vinegar, and ocean water.
Important to Know
When solid sugar, C12H22O11(s), appears to “melt” in your mouth, it does not become
liquid sugar, C12H22O11(l). It dissolves and becomes aqueous sugar, C12H22O11(aq).
Most substances are a mixture of compounds. For example, an orange is a mixture of
water, H2O, fructose, C6H12O6, citric acid, C6H8O7, limonene, C10H16, and many other
compounds. Notice that in mixtures, the components are not combined in a specific
ratio. Some oranges are sweeter or more sour or more juicy because they have more
fructose or citric acid or water than other oranges. But the ratios of the elements in
compounds never change. Water is always water, H2O.
Key Terms
element
chemical symbol
compound
chemical formula
phase
aqueous
Lesson Summary
What do chemical names and symbols tell you about matter
All matter is composed of elements. Each element has a unique symbol. Elements
combine with one another to form compounds. A chemical formula specifies which
elements are present in a compound. The letters in chemical formulas are symbols for
the elements, and the subscript numbers indicate the amount of each element in that
substance. A chemical formula may also include the lowercase letters, (s), (g), (l), and
(aq), which stand for solid, gas, liquid, and aqueous.
Exercises
Reading Questions
1.
Describe the difference between an element and a compound.
2.
What is meant by physical form?
Reason and Apply
3.
How many elements are included in the chemical formula for sodium nitrate, NaNO3?
Name them.
4.
What is the difference between NaOH(s) and NaOH(aq)?
5.
You see a ring with a stone that looks like a diamond but wonder why it’s so cheap. The
jeweler says the stone is a type of diamond called cubic zirconia. How can chemical
symbols prove that cubic zirconia is not a diamond?
6.
Lab Prep Read the Lab: The Copper Cycle on the next page, paying special attention to
the safety instructions. Describe each step that may be dangerous in this lab. Be
prepared to pass a safety quiz before the lab.
CAREER
CONNECTION
Jewelers can tell if a diamond is real based on properties such as hardness, density,
and how it bends light.
Unit 1:Alchemy:Lesson 6