CHAPTER 1
Chemistry: An Introduction
1. The specific answer will depend on student experiences. In general, students are intimidated by
chemistry because they perceive it to be highly mathematical, requiring a great deal of
memorization, and having a difficult technical vocabulary. Many students taking chemistry as a
foundation science cannot see its relevance to their major.
2. The answer will depend on student examples.
3. There are obviously many such examples. Many new drugs and treatments have recently become
available thanks to research in biochemistry and cell biology. New long-wearing, more
comfortable contact lenses have been produced by research in polymer and plastics chemistry.
Special plastics and metals were prepared for the production of compact discs to replace vinyl
phonograph records. As for the “dark side,” chemistry contributes increased global pollution if
not conducted carefully.
4. Answer depends on student responses/examples.
5. This answer depends on your own experience.
6. This answer depends on your own experience, but consider the following examples: oven cleaner
(the label says it contains sodium hydroxide; it converts the burned-on grease in the oven to a
soapy material that washes away); drain cleaner (the label says it contains sodium hydroxide; it
dissolves the clog of hair in the drain); stomach antacid (the label says it contains calcium
carbonate; it makes me belch and makes my stomach feel better); hydrogen peroxide (the label
says it is a 3% solution of hydrogen peroxide; when applied to a wound, it bubbles); depilatory
cream (the label says it contains sodium hydroxide; it removes unwanted hair from skin).
7. David and Susan first recognized the problem (unexplained medical problems). A possible
explanation was then proposed (the glaze on their china might be causing lead poisoning). The
explanation was tested by experiment (it was determined that the china did contain lead). A full
discussion of this scenario is given in the text.
8. The scientist must recognize the problem and state it clearly, propose possible solutions or
explanations, and then decide through experimentation which solution or explanation is best.
9. A law tells what happens; a theory is our attempt to explain why it happens. Examples of laws
include the law of conservation of mass and the ideal gas law (for gases). A theory includes
Einstein’s theory of general relativity.
10. Answer depends on student response. A quantitative observation must include a number. For
example “There are two windows in this room” represents a quantitative observation, but “The
walls of this room are yellow” is a qualitative observation.
1
,Chapter 1: An Introduction
11. Flow charts will vary. Figure 1.1 in the textbook shows a nice example with various parts of the
scientific method. The first step in the scientific method is to state the problem and collect data
(make observations). Observations may be qualitative or quantitative. The next step is to
formulate hypotheses. A hypothesis is a possible explanation for the observation. The final step is
to perform experiments. An experiment is something we do to test the hypothesis. We gather new
information that allows us to decide whether the hypothesis is supported by the new information
we have learned from the experiment. Experiments always produce new observations, and this
brings us back to the beginning of the process again. To explain the behavior of a given part of
nature, we repeat these steps many times. Laws and theories come out of applying the scientific
method.
12. False. Theories can be refined and changed because they are interpretations. They represent
possible explanations of why nature behaves in a particular way. Theories are refined by
performing experiments and making new observations, not by proving the existing observations
as false (which is something that can be witnessed and recorded).
13. Answer depends on student responses/examples.
14. Scientists are human, too. When a scientist formulates a hypothesis, he or she wants it to be
proven correct. In academic research, for example, scientists want to be able to publish papers on
their work to gain renown and acceptance from their colleagues. In industrial situations, the
financial success of the individual and of the company as a whole may be at stake. Politically,
scientists may be under pressure from the government to "beat the other guy."
15. Chemistry is not just a set of facts that have to be memorized. To be successful in chemistry, you
have to be able to apply what you have learned to new situations, new phenomena, and new
experiments. Rather than just learning a list of facts or studying someone else’s solution to a
problem, your instructor hopes you will learn how to solve problems yourself, so that you will be
able to apply what you have learned in future circumstances.
16. Chemistry is not merely a list of observations, definitions, and properties. Chemistry is the study
of very real interactions among different samples of matter, whether within a living cell, or in a
chemical factory. When we study chemistry, at least in the beginning, we try to be as general and
as nonspecific as possible, so that the basic principles learned can be applied to many situations.
In a beginning chemistry course, we learn to interpret and solve a basic set of very simple
problems in the hope that the method of solving these simple problems can be extended to more
complex real life situations later on. The actual solution to a problem, at this point, is not as
important as learning how to recognize and interpret the problem, and how to propose reasonable,
experimentally testable hypotheses.
17. In real life situations, the problems and applications likely to be encountered are not simple
textbook examples. One must be able to observe an event, hypothesize a cause, and then test this
hypothesis. One must be able to carry what has been learned in class forward to new, different
situations.
18. A good student will: learn the background and fundamentals of the subject from their classes and
textbook; will develop the ability to recognize and solve problems and to extend what was
learned in the classroom to “real” situations; will learn to make careful observations; and will be
able to communicate effectively. While some academic subjects may emphasize use of one or
more of these skills, Chemistry makes extensive use of all of them.
2
,CHAPTER 2
Measurements and Calculations
1. measurement
2. “Scientific notation” means we have to put the decimal point after the first significant figure, and
then express the order of magnitude of the number as a power of ten. So we want to put the
decimal point after the first 2:
2,421 2.421 × 10to some power
To be able to move the decimal point three places to the left in going from 2,421 to 2.421, means
I will need a power of 103 after the number, where the exponent 3 shows that I moved the decimal
point 3 places to the left.
2,421 2.421 × 10to some power = 2.421 × 103
3. a. 9.651
b. 3.521
c. 9.3241
d. 1.002
4. a. 107
b. 10–1
c. 10–5
d. 1012
5. a. positive
b. positive
c. negative
d. negative
6. a. negative
b. zero
c. negative
d. positive
7. a. The decimal point must be moved one space to the right, so the exponent is negative;
0.5012 = 5.012 × 10–1.
b. The decimal point must be moved six spaces to the left, so the exponent is positive;
5,012,000 = 5.012 × 106.
3
, Chapter 2: Measurements and Calculations
c. The decimal point must be moved six spaces to the right, so the exponent is negative;
0.000005012 = 5.012 × 10–6.
d. The decimal point does not have to be moved, so the exponent is zero;
5.012 = 5.012 × 100.
e. The decimal point must be moved three spaces to the left, so the exponent is positive;
5012 = 5.012 × 103.
f. The decimal point must be moved three spaces to the right, so the exponent is negative;
0.005012 = 5.012 × 10–3.
8. a. The decimal point must be moved three spaces to the right: 2,789
b. The decimal point must be moved three spaces to the left: 0.002789
c. The decimal point must be moved seven spaces to the right: 93,000,000
d. The decimal point must be moved one space to the right: 42.89
e. The decimal point must be moved 4 spaces to the right: 99,990
f. The decimal point must be moved 5 spaces to the left: 0.00009999
9. a. six spaces to the right
b. five spaces to the left
c. one space to the right
d. The decimal point does not have to be moved.
e. 18 spaces to the right
f. 16 spaces to the left
10. a. three spaces to the left
b. one space to the left
c. five spaces to the right
d. one space to the left
e. two spaces to the right
f. two spaces to the left
11. To say that scientific notation is in standard form means that you have a number between 1 and
10, followed by an exponential term.
a. The decimal point must be moved 4 spaces to the left, so the exponent will be 4:
9.782 × 104
b. 42.14 must first be converted to 4.214 × 101 and then the exponents combined:
4.214 × 104
c. 0.08214 must first be converted to 8.214 × 10–2 and then the exponents combined:
8.214 × 10–5
d. The decimal point must be moved four spaces to the right, so the exponent will be –4:
3.914 × 10–4
4
Chemistry: An Introduction
1. The specific answer will depend on student experiences. In general, students are intimidated by
chemistry because they perceive it to be highly mathematical, requiring a great deal of
memorization, and having a difficult technical vocabulary. Many students taking chemistry as a
foundation science cannot see its relevance to their major.
2. The answer will depend on student examples.
3. There are obviously many such examples. Many new drugs and treatments have recently become
available thanks to research in biochemistry and cell biology. New long-wearing, more
comfortable contact lenses have been produced by research in polymer and plastics chemistry.
Special plastics and metals were prepared for the production of compact discs to replace vinyl
phonograph records. As for the “dark side,” chemistry contributes increased global pollution if
not conducted carefully.
4. Answer depends on student responses/examples.
5. This answer depends on your own experience.
6. This answer depends on your own experience, but consider the following examples: oven cleaner
(the label says it contains sodium hydroxide; it converts the burned-on grease in the oven to a
soapy material that washes away); drain cleaner (the label says it contains sodium hydroxide; it
dissolves the clog of hair in the drain); stomach antacid (the label says it contains calcium
carbonate; it makes me belch and makes my stomach feel better); hydrogen peroxide (the label
says it is a 3% solution of hydrogen peroxide; when applied to a wound, it bubbles); depilatory
cream (the label says it contains sodium hydroxide; it removes unwanted hair from skin).
7. David and Susan first recognized the problem (unexplained medical problems). A possible
explanation was then proposed (the glaze on their china might be causing lead poisoning). The
explanation was tested by experiment (it was determined that the china did contain lead). A full
discussion of this scenario is given in the text.
8. The scientist must recognize the problem and state it clearly, propose possible solutions or
explanations, and then decide through experimentation which solution or explanation is best.
9. A law tells what happens; a theory is our attempt to explain why it happens. Examples of laws
include the law of conservation of mass and the ideal gas law (for gases). A theory includes
Einstein’s theory of general relativity.
10. Answer depends on student response. A quantitative observation must include a number. For
example “There are two windows in this room” represents a quantitative observation, but “The
walls of this room are yellow” is a qualitative observation.
1
,Chapter 1: An Introduction
11. Flow charts will vary. Figure 1.1 in the textbook shows a nice example with various parts of the
scientific method. The first step in the scientific method is to state the problem and collect data
(make observations). Observations may be qualitative or quantitative. The next step is to
formulate hypotheses. A hypothesis is a possible explanation for the observation. The final step is
to perform experiments. An experiment is something we do to test the hypothesis. We gather new
information that allows us to decide whether the hypothesis is supported by the new information
we have learned from the experiment. Experiments always produce new observations, and this
brings us back to the beginning of the process again. To explain the behavior of a given part of
nature, we repeat these steps many times. Laws and theories come out of applying the scientific
method.
12. False. Theories can be refined and changed because they are interpretations. They represent
possible explanations of why nature behaves in a particular way. Theories are refined by
performing experiments and making new observations, not by proving the existing observations
as false (which is something that can be witnessed and recorded).
13. Answer depends on student responses/examples.
14. Scientists are human, too. When a scientist formulates a hypothesis, he or she wants it to be
proven correct. In academic research, for example, scientists want to be able to publish papers on
their work to gain renown and acceptance from their colleagues. In industrial situations, the
financial success of the individual and of the company as a whole may be at stake. Politically,
scientists may be under pressure from the government to "beat the other guy."
15. Chemistry is not just a set of facts that have to be memorized. To be successful in chemistry, you
have to be able to apply what you have learned to new situations, new phenomena, and new
experiments. Rather than just learning a list of facts or studying someone else’s solution to a
problem, your instructor hopes you will learn how to solve problems yourself, so that you will be
able to apply what you have learned in future circumstances.
16. Chemistry is not merely a list of observations, definitions, and properties. Chemistry is the study
of very real interactions among different samples of matter, whether within a living cell, or in a
chemical factory. When we study chemistry, at least in the beginning, we try to be as general and
as nonspecific as possible, so that the basic principles learned can be applied to many situations.
In a beginning chemistry course, we learn to interpret and solve a basic set of very simple
problems in the hope that the method of solving these simple problems can be extended to more
complex real life situations later on. The actual solution to a problem, at this point, is not as
important as learning how to recognize and interpret the problem, and how to propose reasonable,
experimentally testable hypotheses.
17. In real life situations, the problems and applications likely to be encountered are not simple
textbook examples. One must be able to observe an event, hypothesize a cause, and then test this
hypothesis. One must be able to carry what has been learned in class forward to new, different
situations.
18. A good student will: learn the background and fundamentals of the subject from their classes and
textbook; will develop the ability to recognize and solve problems and to extend what was
learned in the classroom to “real” situations; will learn to make careful observations; and will be
able to communicate effectively. While some academic subjects may emphasize use of one or
more of these skills, Chemistry makes extensive use of all of them.
2
,CHAPTER 2
Measurements and Calculations
1. measurement
2. “Scientific notation” means we have to put the decimal point after the first significant figure, and
then express the order of magnitude of the number as a power of ten. So we want to put the
decimal point after the first 2:
2,421 2.421 × 10to some power
To be able to move the decimal point three places to the left in going from 2,421 to 2.421, means
I will need a power of 103 after the number, where the exponent 3 shows that I moved the decimal
point 3 places to the left.
2,421 2.421 × 10to some power = 2.421 × 103
3. a. 9.651
b. 3.521
c. 9.3241
d. 1.002
4. a. 107
b. 10–1
c. 10–5
d. 1012
5. a. positive
b. positive
c. negative
d. negative
6. a. negative
b. zero
c. negative
d. positive
7. a. The decimal point must be moved one space to the right, so the exponent is negative;
0.5012 = 5.012 × 10–1.
b. The decimal point must be moved six spaces to the left, so the exponent is positive;
5,012,000 = 5.012 × 106.
3
, Chapter 2: Measurements and Calculations
c. The decimal point must be moved six spaces to the right, so the exponent is negative;
0.000005012 = 5.012 × 10–6.
d. The decimal point does not have to be moved, so the exponent is zero;
5.012 = 5.012 × 100.
e. The decimal point must be moved three spaces to the left, so the exponent is positive;
5012 = 5.012 × 103.
f. The decimal point must be moved three spaces to the right, so the exponent is negative;
0.005012 = 5.012 × 10–3.
8. a. The decimal point must be moved three spaces to the right: 2,789
b. The decimal point must be moved three spaces to the left: 0.002789
c. The decimal point must be moved seven spaces to the right: 93,000,000
d. The decimal point must be moved one space to the right: 42.89
e. The decimal point must be moved 4 spaces to the right: 99,990
f. The decimal point must be moved 5 spaces to the left: 0.00009999
9. a. six spaces to the right
b. five spaces to the left
c. one space to the right
d. The decimal point does not have to be moved.
e. 18 spaces to the right
f. 16 spaces to the left
10. a. three spaces to the left
b. one space to the left
c. five spaces to the right
d. one space to the left
e. two spaces to the right
f. two spaces to the left
11. To say that scientific notation is in standard form means that you have a number between 1 and
10, followed by an exponential term.
a. The decimal point must be moved 4 spaces to the left, so the exponent will be 4:
9.782 × 104
b. 42.14 must first be converted to 4.214 × 101 and then the exponents combined:
4.214 × 104
c. 0.08214 must first be converted to 8.214 × 10–2 and then the exponents combined:
8.214 × 10–5
d. The decimal point must be moved four spaces to the right, so the exponent will be –4:
3.914 × 10–4
4
