Type:
Solution Manual
Resource:
Chemistry for Changing Times
Edition:
13th Edition
Author(s):
John W. Hill Doris K. Kolb Terry W. McCreary
Chapter 1: Chemistry Overview Chapter 1 introduces the student to the concepts of science—its ability to solve problems as well as its limitations. The student is then introduced to the concept of matter and energy and the physical means by which they are measured. Lecture Outline 1.1
1.2 1.3
1.4 1.5 1.6 1.7
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Science and Technology: The Roots of Knowledge Many students are confused about the differences between science and technology. Technology is the direct application of knowledge to solve problems. Science seeks an understanding of underlying principles. Changing Perceptions and Changing Practices Science: Reproducible, Testable, Tentative, Predictive, and Explanatory The scientific method, from hypothesis to law, theory, or model. is best explained by example. Science and Technology: Risks and Benefits Chemistry: Its Central Role Solving Society’s Problems: Scientific Research Research can be basic or applied. Chemistry: A Study of Matter and Its Changes Matter is anything that has mass. Mass is a measure of the amount of matter present. Weight is mass times gravitational attraction. Matter exhibits chemical and physical properties. Chemical properties tell us how matter will combine to form new and different substances (a chemical change). Physical properties are directly observable: Color, state (solid, liquid, or gas), and texture are examples. An excellent demonstration is to burn a candle (chemical change) and boil water (physical change). Classification of Matter (a) States of Matter • Solids, liquids, and gases (b) Substances and Mixtures • Substances have constant composition. • The composition of a mixture is variable. ▪ Homogeneous mixtures appear the same throughout (milk, paint, and saltwater are examples). ▪ Heterogeneous mixtures appear different throughout (pizza, raisin bread, and chocolate chip cookies are examples.) (c) Elements and Compounds • Substances are either elements or compounds.
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Elements are fundamental building blocks of all matter. Lead, silver, gold, carbon, and oxygen are examples. ▪ Compounds are two or more elements chemically combined in fixed ratios. Water, ammonia. and propane are examples. (d) Atoms and Molecules The Measurement of Matter Most students have been introduced to the metric system during their K–12 education; the SI system used in science is based on the metric system. The difference lies in the base units. • Base units: kilograms (kg) for mass, meter (m) for length, and seconds (s) for time. The four other base units are shown in Table 1.4. Density Density is the mass-to-volume ratio of matter. Energy: Heat and Temperature The SI unit of temperature is the kelvin (K); however, the temperature scale used in the chemistry laboratory is usually the Celsius scale. The Celsius scale was developed with the freezing and boiling points of pure water at a pressure of 1 atmosphere as the reference frames. (Students find the history of the development of the Fahrenheit scale much more interesting!) Critical Thinking
Demonstrations 1. Place samples of various elements (e.g., copper, sulfur, zinc, mercury, aluminum, carbon, etc.) in small stoppered bottles or flasks that can be passed around. 2. Ask students: "Which is heavier: lead or aluminum?" They will say "lead". Then bring out two flasks, a 50-mL flask with about 10 mL of lead shot and a 500-mL flask about 3/4 full of aluminum pellets. Point out that the aluminum is heavier. But we need to compare samples of the same size (volume). Weight per unit volume is density. Lead has the greater density. 3. Compare a yardstick and a meter stick. A meter is slightly bigger than a yard. A sugar cube is approximately 1 mL. An ordinary paper clip weighs about 1 gram. A liter is a little bit (6%) larger than a quart. 4. Use Crispix® and Raisin Bran® to illustrate the difference between a compound and a mixture. Raisins and bran flakes are easily separated, and the ratio of raisins to flakes can vary. Crispix® has a 1:1 ratio of corn and rice flakes, and they cannot be easily separated.
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