UNDERSTANDING THE CONCEPTS
The chaprer Secrians ro review are shown in paremheses arrhe end of
each problem.
1.35 A “chemical-free” shampoo includes the following ingredients:
water, cocamide, glycerin, and c itric acid. Is the shampoo truly
“chemical-free”? (1 .1)
1.36 A “chemical-free” sunscreen includes the following ingredients:
titanium dioxide, vitamin E, and vitamin C. Is the sunscreen
truly “chemical-free”? ( I. I)
1.37 According to Sherlock Holmes, “One must follow the rules of
scientific inquiry, gathering, observing, and testing data, then
formulating, modifying, and rejecting hypotheses, until only
one remains.” Did Holmes use the scientific method? Why or
why not? ( 1.2)
1.38 In A Scandal in Bohemia, Sherlock Holmes receives a mysterious
note. He states, “I have no data yet. It is a capital mistake
to theorize before one has data. Insensibly one begins to twist
facts to suit theories, instead of theories to suit facts.” What do
you think Holmes meant? (1.2)
1.39 For each of the following, indicate if the answer has a positive
or negative sign: ( 1.4)
a . Two negative numbers are added.
b. A positive and negative number are multiplied.
ADDITIONAL PRACTICE PROBLEMS
1.43 Select the correct phrase(s) to complete the following statement:
If experimental results do not support your hypothesis, you
should ( 1.2)
a . pretend that the experimental results support your
hypothesis
b. modify your hypothesis
c. do more experiments
1.44 Select the correct phrase(s) to complete the following statement:
A hypothesis is confirmed when ( 1.2)
a . one experiment proves the hypothesis
b. many experiments validate the hypothesis
c. you think your hypothesis is correct
1.45 Which of the following will help you develop a successful
study plan? (1.3)
a . skipping cla~s and just reading the text
b. working the Sample Problems as you go through a chapter
c. self-testing
d. reading through the chapter, but working the problems later
1.46 Which of the following will help you develop a successful
study plan? (1.3)
a . studying all night before the exam
b. forming a study group and discussing the problems together
c. working problems in a notebook for easy reference
d. highlighting important idea~ in the text
1.47 Evaluate each of the following: ( 1.4)
a . 4X(- 8)= __ b. – 12 – 48=
- 168
c. — = - 4
1.48 Evaluate each of the following: ( 1.4)
a . – 95 – (- II)= __
c. 4 – 56=
152
b. =t9 =
Additional Practice Problems 23
1.40 For each of the following, indicate if the answer has a positive
or negative s ign: (1.4)
a. A negative number is subtracted from a positive number.
b. Two negative numbers are divided.
Clinical Applications
1.41 Classify each of the following statements a~ an observation
or a hypothesis: (1.2)
a. A patient breaks out in hives after receiving penicillin.
b. Dinosaurs became extinct when a large meteorite struck
Earth and caused a huge dust cloud that severely decreased
the amount of light reaching Earth.
c. A patient’s blood pressure wa~ l iOns.
1.42 Classify each of the following statements a~ an observation
or a hypothesis: (1.2)
a. Analysis of I 0 ceramic dishes showed that four dishes
contained lead levels that exceeded federal safety
standards.
b. Marble statues undergo corrosion in acid rain.
c. A child with a high fever and a rash may have chickenpox.
1.49 A bag of gumdrops contains 16 orange gumdrops, 8 yellow
gumdrops, and 16 black gumdrops. ( 1.4)
a. What is the percentage of yellow gumdrops? Express your
answer to the ones place.
b. What is the percentage of black gumdrops? Express your
answer to the ones place.
1.50 On the first chemistry test, 12 students got As, 18 students got
Bs, and 20 students got Cs. ( 1.4)
a. What is the percentage of student~ who received Bs?
Express your answer to the ones place.
b. What is the percentage of student~ who received Cs?
Express your answer to the ones place.
1.51 Write each of the following in scientific notation: ( 1.5)
a. 120 000 b. 0.000 000 34
c. 0.066 d. 2700
1.52 Write each of the following in scientific notation: ( 1.5)
a. 0.0042 b. 310
c. 890 000 000 d. 0.000 000 056
Clinical Applications
1.53 Identify each of the following as an observation, a hypothesis,
an experiment, or a conclusion: ( 1.2)
a. A patient has a high fever and a ra~h on her back.
b. A nurse tells a patient that her baby who gets s ick after
drinking milk may be lactose intolerant.
c. Numerous studies have shown that omega-3 fatty acids
lower triglyceride levels.
1.54 Identify each of the following as an observation, a hypothesis,
an experiment, or a conclusion: ( 1.2)
a. Every spring, you have congestion and a runny nose.
b. An overweight patient decides to exercise more to Jose weight.
c. Many research studies have linked obesity to heart disease.
1.55 How will each of the following increase your chance of success
in chemistry? ( 1.3)
a. self-testing
b. forming a study group
c. reading an assignment before class
CHALLENGE PROBLEMS
The following problems are relared ro rhe ropics in rhis chaprer. However,
riley do nor all follow rile chaprer order, and riley require youro combine
conceprs and skills from severo/ Seer ions. These problems will help you
increase your criricalrhinking skills and prepare for your nexr exam.
1.57 Cla~sify each of the following as an observation, a hypothesis,
an experiment, or a conclusion: (1 .2)
a. The bicycle tire is flat.
b. If I add air to tl1e bicycle tire, it will expand to the proper size.
c. When I added air to the bicycle tire, it wa~ sti ll flat.
d. The bicycle tire ha~ a leak in it.
1.58 Cla~sify each of the following as an observation, a hypothesis,
an experiment, or a conclusion: (1 .2)
a. A big log in the fire does not burn well.
b. lf I chop the log into smaller wood pieces, it will burn
better.
c. The small wood pieces burn brighter and make a hotter fire.
d. The small wood pieces are used up faster than burning the
big log.
1.59 Solve each of the following for x: ( 1.4)
5x
a. 2x + 5 = 41 b. 3 = 40
1.60 Solve each of the following for z: ( 1.4)
a. 3z- (-6) = 12 b. ~~2 = -8
ANSWERS
1.56 How will each of the following decrea~e your c hance of success
in chemistry? ( 1.3)
a. studying only the night before an exam
b. not going to class
c. not practic ing the problems in the text
Use the following graph for problems 1.61 and 1.62:
~.
0 u
Solubility of Carbon Dioxide in Water versus Temperature
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0′—–‘——‘–.—–‘—-‘—–
0 10 20 30 40 50 60
Temperature (“C)
1.61 a. What does the title indicate about the graph? ( 1.4)
b. What is mea~ured on the vertical ax is?
c. What is the range of values on the vertical axis?
d. Does the solubility of carbon dioxide increase or decrease
with an increa~e in temperature?
1.62 a. What is mea~ured on the horizontal ax is? ( 1.4)
b. What is the range of values on the horizontal axis?
c. What is the solubility of carbon dioxide in water at 25 •c?
d. At what temperature does carbon dioxide have a solubility
of0.20 g/100 g water?
1.1 a. Chemistry is the study of the composition, structure, prop- 1.13 a, c, and e
e rties, and reactions of matter.
b. A chemical is a substance that has the same composition
and properties wherever it is found.
1.3 Many chemicals are listed on a vitamin bottle such as
vitamin A, vitamin 8 3, vitamin 8 12, vitamin C, and folic acid.
1.5 Typical items found in a medicine cabinet and some of the
chemicals they contain are as follows:
1.7
1.9
Anracid rablers: calcium carbonate, cellulose, s tarch, stearic
acid, si licon dioxide
MoUThwash: water, alcohol, thymol, glycerol, sodium benzoate,
benzoic acid
Cough suppressanT: menthol, beta-carotene, sucrose, g lucose
a. observation b. hypothesis c. experiment
d. observation e. observation f. conclus ion
a. observation b. hypothesis
c. experiment d. experiment
1.11 There are several things you can do that wi ll help you successfu
lly Jearn chemistry: forming a study group, retesting, doing
Try It First before reading the Solution, checking Review,
working Sample Problems and Study Checks, working Practice
Problems and checking Answers, read ing the assignment ahead
of class, and keeping a problem notebook.
1.15
1.17
1.19
1.21
a.
a.
a.
a.
thousandths
23
84%
9
b. ones c. hundreds
b. -30 c. – 2
b. 72% c. 30%
b. 42
1.23 a. The graph shows the relationsh ip between the temperature
of a cup of tea and time.
b. temperature, in •c
c. 20 •c to 80 •c
d. decrea~e
1.25 a. This graph shows the relationship between body temperature
and time s ince death.
b. temperature, in •c
c. 20 •c to40 •c
d. decrea~e
1.27 a. 5.5 X ]()” b. 4.8 X 102 c. 5 X 10-6
d. 1.4 X 10- 4 e. 7.2 X 10-J f. 6.7 X lOS
1.29 a. 7.2 X 103 b. 3.2 X 10-2
c. I X 104 d. 6.8 X 10-2
1.31 a. hypothesis b. conclusion
c. experiment d. observation
1.33 27% e th ylene glycol
1.35 No. All of the ingredients are chemicals.
1.37 Yes. Sherlock’s investigation includes malting observations
(gathering data). formulating a hypothesis. testing the hypothesis.
and modifying it until one of the hypotheses is validated.
1.39 a. negative b. negative
1.41 a. observation
1.43 b and c
1.45 b and c
1.47
1.49
1.5 1
1.53
a.
a.
a.
c.
a.
-32
20’k
1.2 X I~
6.6 X 10- 2
observation
b. hypothesis
b. – 60
b. 40%
b. 3.4 X 10- 7
d. 2.7 X llY
b. hypothesis
c. observation
c. 42
c. conclusion
Answers 25
1.55 a. Self-testin g allows yo u to chec k o n what you understand.
b. Forming a study group can motivate you to study. fill in gaps,
and correct mi sunderstandings by teaching and learning
together.
c. Reading the assignment before class prepares you to learn
new material.
1.57 a. observation
c. experiment
1 . .59 a. 18
b. hypothes is
d. conclusion
b. 24
1.61 a. 11le graph shows the relationship between the solubility of
carbon dioxide in water and temperature.
b. solubility of carbon dioxide (g COfiOO g water)
c. 0 to 0.35 g of COz/ 1 00 g of water
d. decrease
