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Solving Problems: A Chemistry Handbook
Chemistry: Matter and Change
21
Matter—Properties and
Changes
Matter—Properties and
Changes
SOLVING PROBLEMS:
A CHEMISTRY HANDBOOK
CHAPTER
3
3.1 Properties of Matter
All of the material—the “stuff”—around us is matter. A substance
is matter that has a uniform and unchanging composition. For example, water is a pure substance. No matter where it is found, a sample
of water will have the same composition as any other sample of
water.
A physical property of a substance is a characteristic that can
be observed and measured without changing the composition of the
substance. Words such as hard, soft, shiny, dull, brittle, flexible,
heavy (in density), and light (in density) are used to describe physical properties.
A chemical property describes the ability of a substance to
combine with or change into one or more other substances. For
example, the ability of iron to form rust when combined with air is a
chemical property of iron. The inability of a substance to combine
with another substance is also a chemical property. For example, the
inability to combine with most other substances is a chemical property of gold.
Practice Problems
1. Identify each of the following as an example of a physical
property or a chemical property.
a. Silver tarnishes when it comes in contact with hydrogen sulfide in the air.
b. A sheet of copper can be pounded into a bowl.
c. Barium melts at 725°C.
d. Helium does not react with any other element.
e. A bar of lead is more easily bent than is a bar of aluminum
of the same size.
f. Potassium metal is kept submerged in oil to prevent contact
with oxygen or water.
Solving Problems: A Chemistry Handbook
Chemistry: Matter and Change
21
Matter—Properties and
Changes
Matter—Properties and
Changes
SOLVING PROBLEMS:
A CHEMISTRY HANDBOOK
CHAPTER
3
3.1 Properties of Matter
All of the material—the “stuff”—around us is matter. A substance
is matter that has a uniform and unchanging composition. For example, water is a pure substance. No matter where it is found, a sample
of water will have the same composition as any other sample of
water.
A physical property of a substance is a characteristic that can
be observed and measured without changing the composition of the
substance. Words such as hard, soft, shiny, dull, brittle, flexible,
heavy (in density), and light (in density) are used to describe physical properties.
A chemical property describes the ability of a substance to
combine with or change into one or more other substances. For
example, the ability of iron to form rust when combined with air is a
chemical property of iron. The inability of a substance to combine
with another substance is also a chemical property. For example, the
inability to combine with most other substances is a chemical property of gold.
Practice Problems
1. Identify each of the following as an example of a physical
property or a chemical property.
a. Silver tarnishes when it comes in contact with hydrogen sulfide in the air.
b. A sheet of copper can be pounded into a bowl.
c. Barium melts at 725°C.
d. Helium does not react with any other element.
e. A bar of lead is more easily bent than is a bar of aluminum
of the same size.
f. Potassium metal is kept submerged in oil to prevent contact
with oxygen or water.