Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Solving Problems: A Chemistry Handbook
Chemistry: Matter and Change
3
SOLVING PROBLEMS:
A CHEMISTRY HANDBOOK
CHAPTER
1
Practice Problems
1. Identify each of the following as an example of qualitative data
or quantitative data.
a. taste of an apple
d. length of a rod
b. mass of a brick
e. texture of a leaf
c. speed of a car
f. weight of an elephant
A hypothesis is a possible explanation for what has been observed.
Based on the observations of ozone thinning and CFC buildup in the
atmosphere, the chemists Mario Molina and F. Sherwood Rowland
hypothesized that CFCs break down in the atmosphere due to the
Sun’s ultraviolet rays. They further hypothesized that a chlorine particle produced by the breakdown of CFCs could break down ozone.
An experiment is a set of controlled observations that test a
hypothesis. In an experiment, a scientist will set up and change one
variable at a time. A variable is a quantity that can have more than
one value. The variable that is changed in an experiment is called
the independent variable. The variable that you watch to see how it
changes as a result of your changes to the independent variable is
called the dependent variable. For example, if you wanted to test
the effect of fertilizer on plant growth, you would change the
amount of fertilizer applied to the same kinds of plants. The amount
of fertilizer applied would be the independent variable in this
experiment. Plant growth would be the dependent variable. Many
experiments also include a control, which is a standard for
comparison; in this case, plants to which no fertilizer is applied.
A conclusion is a judgment based on the data obtained in the
experiment. If data support a hypothesis, the hypothesis is tentatively
affirmed. Hypotheses are never proven; they are always subject to
additional research. If additional data do not support a hypothesis, the
hypothesis is discarded or modified. Most hypotheses are not supported by data. Whether the hypothesis is supported or not, the data
collected may still be useful. Over time, data from many experiments
can be used to form a visual, verbal, and/or mathematical explanation—called a model—of the phenomenon being studied.
A theory is an explanation that has been supported by many
experiments. Theories state broad principles of nature. Although theories are the best explanations of phenomena that scientists have at
Solving Problems: A Chemistry Handbook
Chemistry: Matter and Change
3
SOLVING PROBLEMS:
A CHEMISTRY HANDBOOK
CHAPTER
1
Practice Problems
1. Identify each of the following as an example of qualitative data
or quantitative data.
a. taste of an apple
d. length of a rod
b. mass of a brick
e. texture of a leaf
c. speed of a car
f. weight of an elephant
A hypothesis is a possible explanation for what has been observed.
Based on the observations of ozone thinning and CFC buildup in the
atmosphere, the chemists Mario Molina and F. Sherwood Rowland
hypothesized that CFCs break down in the atmosphere due to the
Sun’s ultraviolet rays. They further hypothesized that a chlorine particle produced by the breakdown of CFCs could break down ozone.
An experiment is a set of controlled observations that test a
hypothesis. In an experiment, a scientist will set up and change one
variable at a time. A variable is a quantity that can have more than
one value. The variable that is changed in an experiment is called
the independent variable. The variable that you watch to see how it
changes as a result of your changes to the independent variable is
called the dependent variable. For example, if you wanted to test
the effect of fertilizer on plant growth, you would change the
amount of fertilizer applied to the same kinds of plants. The amount
of fertilizer applied would be the independent variable in this
experiment. Plant growth would be the dependent variable. Many
experiments also include a control, which is a standard for
comparison; in this case, plants to which no fertilizer is applied.
A conclusion is a judgment based on the data obtained in the
experiment. If data support a hypothesis, the hypothesis is tentatively
affirmed. Hypotheses are never proven; they are always subject to
additional research. If additional data do not support a hypothesis, the
hypothesis is discarded or modified. Most hypotheses are not supported by data. Whether the hypothesis is supported or not, the data
collected may still be useful. Over time, data from many experiments
can be used to form a visual, verbal, and/or mathematical explanation—called a model—of the phenomenon being studied.
A theory is an explanation that has been supported by many
experiments. Theories state broad principles of nature. Although theories are the best explanations of phenomena that scientists have at