Introductory Chemistry: A Foundation - Zumdahl S.S., DeCoste D.J. 2019

Chemistry: An Introduction
Chapter Review

Key Terms

· chemistry (1.2)

· scientific method (1.4)

· measurement (1.4)

· theory (1.4)

· natural law (1.4)

For Review

· Chemistry is important to everyone because chemistry occurs all around us in our daily lives.

· Chemistry is the science that deals with the materials of the universe and the changes that these materials undergo.

· Scientific thinking helps us solve all types of problems that we confront in our lives.

· Scientific thinking involves observations that enable us to clearly define both a problem and the construction and evaluation of possible explanations or solutions to the problem.

· The scientific method is a procedure for processing the information that flows from the world around us in which we

o Make observations.

o Formulate hypotheses.

o Perform experiments.

A flowchart shows steps in the scientific method. Observations lead to hypotheses, which lead to experiments, which produce new observations, by which the process begins again. This cycle leads to a theory or model, which generates predictions tested by experiment, after which the theory is modified as needed.

· Models represent our attempt to understand the world around us.

o Models are not the same as “reality.”

o Elementary models are based on the properties of atoms and molecules.

· Understanding chemistry takes hard work and patience.

· As you learn chemistry, you should be able to understand, explain, and predict phenomena in the macroscopic world by using models based in the microscopic world.

· Understanding is different from memorizing.

· It is acceptable to make mistakes as long as you learn from them.

Active Learning Questions

These questions are designed to be considered by groups of students in class. Often these questions work well for introducing a particular topic in class.

· 1.

Discuss how a hypothesis can become a theory. Can a theory become a law? Explain.

· 2.

Make five qualitative and five quantitative observations about the room in which you now sit.

· 3.

List as many chemical reactions as you can think of that are part of your everyday life. Explain.

· 4.

Differentiate between a “theory” and a “scientific theory.”

· 5.

Describe three situations when you used the scientific method (outside of school) in the past month.

· 6.

Scientific models do not describe reality. They are simplifications and therefore incorrect at some level. So why are models useful?

· 7.

Theories should inspire questions. Discuss a scientific theory you know and the questions it brings up.

· 8.

Describe how you would set up an experiment to test the relationship between completion of assigned homework and the final grade you receive in the course.

· 9.

If all scientists use the scientific method to try to arrive at a better understanding of the world, why do so many debates arise among scientists?

· 10.

As stated in the text, there is no one scientific method. However, making observations, formulating hypotheses, and performing experiments are generally components of “doing science.” Read the following passage, and list any observations, hypotheses, and experiments. Support your answer.

Joyce and Frank are eating raisins and drinking ginger ale. Frank accidentally drops a raisin into his ginger ale. They both notice that the raisin falls to the bottom of the glass. Soon, the raisin rises to the surface of the ginger ale, then sinks. Within a couple of minutes, it rises and sinks again. Joyce asks, “I wonder why that happened?” Frank says, “I don’t know, but let’s see if it works in water.” Joyce fills a glass with water and drops the raisin into the glass. After a few minutes, Frank says, “No, it doesn’t go up and down in the water.” Joyce closely observes the raisins in the two glasses and states, “Look, there are bubbles on the raisins in the ginger ale but not on the raisins in the water.” Frank says, “It must be the bubbles that make the raisin rise.” Joyce asks, “OK, but then why do they sink again?”

· 11.

In Section 1.3 the statement is made that it is worthwhile for scientists, auto mechanics, doctors, politicians, and poets to take a scientific approach to their professions. Discuss how each of these people could use a scientific approach in his or her profession.

· 12.

As part of a science project, you study traffic patterns in your city at an intersection in the middle of downtown. You set up a device that counts the cars passing through this intersection for a -hour period during a weekday. The graph of hourly traffic looks like this.

A bar graph plots the number of cars on the vertical axis against time on the horizontal axis, for a 24-hour period. The number of cars is about 2 at 12 a.m., and it increases gradually to about 11 at 6 a.m. By 7 a.m., the number of cars is 25, and the number increases to 55 by 8 a.m. A gradual decrease is observed between 8 a.m. and noon, when the number is approximately 38. The number decreases further from noon to a low of about 22 at 3 pm, after which it increases again to over 50 at 5 p.m., at which time it increases to over 50. At 6 p.m., the number of cars decreases to about 28 and the decreasing trend continues up to 12 a.m.

a. At what time(s) does the highest number of cars pass through the intersection?

b. At what time(s) does the lowest number of cars pass through the intersection?

c. Briefly describe the trend in numbers of cars over the course of the day.

d. Provide a hypothesis explaining the trend in numbers of cars over the course of the day.

e. Provide a possible experiment that could test your hypothesis.

· 13.

Confronted with the box shown in the diagram, you wish to discover something about its internal workings. You have no tools and cannot open the box. You pull on rope B, and it moves rather freely. When you pull on rope A, rope C appears to be pulled slightly into the box. When you pull on rope C, rope A almost disappears into the box.*

An illustration shows a rectangular box with three holes marked A, B, and C. A piece of rope extends through each hole.

a. Based on these observations, construct a model for the interior mechanism of the box.

b. What further experiments could you do to refine your model?

Questions and Problems: 1.1 Chemistry: An Introduction

Questions and Problems with answers below also have full solutions in the Student Solutions Guide.

Questions

Icon directs you to the Chemistry in Focus feature in the chapter

· 1.

Chemistry is an intimidating academic subject for many students. You are not alone if you are afraid of not doing well in this course! Why do you suppose the study of chemistry is so intimidating for many students? What about having to take a chemistry course bothers you? Make a list of your concerns, and bring them to class for discussion with your fellow students and your instructor.

· 2.

The first paragraphs in this chapter ask you if you have ever wondered how and why various things in our everyday lives happen the way they do. For your next class meeting, make a list of five similar chemistry-related things for discussion with your instructor and the other students in your class.

· 3.

This section presents several ways our day-to-day lives have been enriched by chemistry. List three materials or processes involving chemistry that you feel have contributed to such an enrichment, and explain your choices.

· 4.

Icon The “Chemistry in Focus” segment titled Dr. Ruth—Cotton Hero discusses the enormous contribution of Dr. Ruth Rogan Benerito to the survival of the cotton fabric industry in the United States. In the discussion, it was mentioned that Dr. Benerito became a chemist when women were not expected to be interested in, or good at, scientific subjects. Has this attitude changed? Among your own friends, approximately how many of your female friends are studying a science? How many plan to pursue a career in science? Discuss.

Questions and Problems: 1.2 What Is Chemistry?

Questions and Problems with answers below also have full solutions in the Student Solutions Guide.

Questions

· 5.

This textbook provides a specific definition of chemistry: the study of the materials of which the universe is made and the transformations that these materials undergo. Obviously, such a general definition has to be very broad and nonspecific. From your point of view at this time, how would you define chemistry? In your mind, what are “chemicals”? What do “chemists” do?

· 6.

We use chemical reactions in our everyday lives, too, not just in the science laboratory. Give at least five examples of chemical transformations that you use in your daily activities. Indicate what the “chemical” is in each of your examples and how you recognize that a chemical change has taken place.

Questions and Problems: 1.3 Solving Problems Using a Scientific Approach

Questions and Problems with answers below also have full solutions in the Student Solutions Guide.

Questions

Icon directs you to the Chemistry in Focus feature in the chapter

· 7.

Icon Read the “Chemistry in Focus” segment A Mystifying Problem, and discuss how David and Susan analyzed the situation, arriving at the theory that the lead glaze on the pottery was responsible for their symptoms.

· 8.

Being a scientist is very much like being a detective. Detectives such as Sherlock Holmes or Miss Marple perform a very systematic analysis of a crime to solve it, much like a scientist does when addressing a scientific investigation. What are the steps that scientists (or detectives) use to solve problems?

Questions and Problems: 1.4 The Scientific Method

Questions and Problems with answers below also have full solutions in the Student Solutions Guide.

Questions

· 9.

In science, what is the difference between a law and a theory? Provide examples of each.

· 10.

Observations may be either qualitative or quantitative. Quantitative observations are usually referred to as measurements. List five examples of qualitative observations you might make around your home or school. List five examples of measurements you might make in everyday life.

· 11.

Sketch a flowchart of the steps in the scientific method. Then define each part of the method.

· 12.

True or false? If a theory is disproven, then all of the observations that support that theory are also disproven. Explain.

o True

o False

· 13.

Although, in general, science has advanced our standard of living tremendously, there is sometimes a “dark side” to science. Give an example of the misuse of science, and explain how this has had an adverse effect on our lives.

· 14.

Discuss several political, social, or personal considerations that might affect a scientist’s evaluation of a theory. Give examples of how such external forces have influenced scientists in the past. Discuss methods by which such bias might be excluded from future scientific investigations.

Questions and Problems: 1.5 Learning Chemistry

Questions and Problems with answers below also have full solutions in the Student Solutions Guide.

Questions

Icon directs you to the Chemistry in Focus feature in the chapter

· 15.

Although reviewing your lecture notes and reading your textbook are important, why does the study of chemistry depend so much on problem solving? Can you learn to solve problems yourself just by looking at the solved examples in your textbook or study guide? Discuss.

· 16.

Why is the ability to solve problems important in the study of chemistry? Why is it that the method used to attack a problem is as important as the answer to the problem itself?

· 17.

Students approaching the study of chemistry must learn certain basic facts (such as the names and symbols of the most common elements), but it is much more important that they learn to think critically and to go beyond the specific examples discussed in class or in the textbook. Explain how learning to do this might be helpful in any career, even one far removed from chemistry.

· 18.

Icon The “Chemistry in Focus” segment Chemistry: An Important Component of Your Education discusses how studying chemistry can be beneficial not only in your chemistry courses but in your studies in general. What are some characteristics of a good student, and how does studying chemistry help achieve these characteristics?