Type:
Solution Manual
Resource:
Chemistry A Molecular Approach
Edition:
1st Edition
Author(s):
Nivaldo J. Tro
Chapter 1. Units of Measurement for Physical and Chemical Change Student Objectives 1.1 Physical and Chemical Changes and Physical and Chemical Properties
Define, recognize, and understand the difference between physical and chemical changes.
1.2 Energy: A Fundamental Part of Physical and Chemical Change
Define energy, work, kinetic energy, potential energy, and thermal energy. State and understand the law of conservation of energy.
1.3 The Units of Measurement
Understand the importance of reporting correct units with measurements. Know the differences between the three most common sets of units: English system, metric system, and International System (SI). Know the SI base units for length, mass, time, and temperature. Know the three most common temperature scales (Fahrenheit, Celsius, and Kelvin), the freezing and boiling points of water on each scale, and the relationships between the scales. Calculate temperature conversions between each scale. Know and use the SI prefix multipliers for powers of ten.
1.4 The Reliability of a Measurement
Understand that all measurements have some degree of uncertainty and that the last digit in a measurement is estimated. Know how to determine the number of significant figures in a measurement using a set of rules. Know how to determine the number of significant figures after calculations. Distinguish between accuracy and precision.
1.5 Solving Chemical Problems
Understand dimensional analysis and know how to use conversion factors. Understand the problem‐solving strategy: sort, strategize, solve, and check. Convert from one unit to another. Make order‐of‐magnitude estimations without using a calculator. Rearrange algebraic equations to solve for unknown variables.
.
2
Chapter 1. Units of Measurement for Physical and Chemical Change Section Summaries Lecture Outline
Terms, Concepts, Relationships, Skills Figures, Tables, and Solved Examples
Teaching Tips
Suggestions and Examples Misconceptions and Pitfalls
.
3
Chapter 1. Units of Measurement for Physical and Chemical Change Lecture Outline Terms, Concepts, Relationships, Skills
Figures, Tables, and Solved Examples
1.1 Physical and Chemical Changes and Physical and Chemical Properties Differences between physical and chemical changes Examples and classifying changes
1.2 Energy: A Fundamental Part of Physical and Chemical Change Definitions of work and energy Classification and types of energy o kinetic thermal o potential Definition and examples of the law of conservation of energy
Figure 1.1 Boiling Is a Physical Change and Rusting Is a Chemical Change
.
Figure 1.2 Energy Conversions Figure 1.3 Using Chemical Energy to Do Work
4
Chapter 1. Units of Measurement for Physical and Chemical Change Teaching Tips Suggestions and Examples
Misconceptions and Pitfalls
1.1 Physical and Chemical Changes and Physical and Chemical Properties Conceptual Connection 1.1 Chemical and Physical Changes
1.2 Energy: A Fundamental Part of Physical and Chemical Change The examples of work being done by a person moving a box and chemical energy ultimately moving the car are consistent and simple. Additional examples using gravitation (very familiar) are straightforward. Several examples are cited for the law of conservation of energy; ask students to name and describe other forms of energy (solar, mechanical, chemical, electrical) and devices that convert between these forms.
.
Boiling (especially) does not change a substance’s chemical identity. Confront the confusion that can occur when a physical change accompanies a chemical one: burning liquid gasoline produces gases (physical or chemical or both?).
Work is a form of energy and thus has the same units as energy.
5
Chapter 1. Units of Measurement for Physical and Chemical Change Lecture Outline Terms, Concepts, Relationships, Skills
Figures, Tables, and Solved Examples
1.3 The Units of Measurement Loss of Mars Climate Orbiter because of inconsistent units Systems of measurement and units o English system o metric system o International System (SI) SI base units o length: metre o mass: kilogram o time: second o temperature: Kelvin Temperature scales and conversions o Fahrenheit to Celsius and vice versa o Celsius to Kelvin and vice versa Derived units o volume (cubic metre, cubic centimetre, litre, millilitre) o density, mass per unit volume (g mL‐1, g cm‐3)
1.4 The Reliability of a Measurement Significance and reporting of numerical values o estimating measurements Counting significant figures or digits o nonzero digits o interior zeroes o leading zeroes o trailing zeroes o exact numbers Significant figures in calculations o multiplication and division (fewest significant figures) o addition and subtraction (fewest decimal places) o rounding Precision vs. accuracy Scientific integrity and data reporting
.
Unnumbered figure: Air Canada Flight 143 Table 1.1 SI Base Units Unnumbered figure: The CN Tower is 553.3 metres tall; a hockey player is about 2 metres tall Figure 1.4 Comparison of the Celsius and Kelvin Temperature Scales Example 1.1 Converting Between Temperature Scales Table 1.2 Metric Prefixes Example 1.2 Converting Between Different SI Prefixes Figure 1.5 The Relationship between Length and Volume Table 1.3 Some Common Derived Units Table 1.4 The Density of Some Common Substances at 20 °C Example 1.3 Calculating Density and Converting Density Units Chemistry and Medicine: Bone Density Table 1.5 Common Derived Units with Special Names
Table 1.6 Maximum August Temperatures in St. John’s, NL and Windsor, ON Figure 1.6 Estimation in Weighing Example 1.4 Reporting the Correct Number of Digits Example 1.5 Determining the Number of Significant Figures in a Number Example 1.6 Significant Figures in Calculations The Nature of Science: Integrity in Data Gathering Unnumbered figure: Accuracy and precision
6
Chapter 1. Units of Measurement for Physical and Chemical Change Teaching Tips Suggestions and Examples
Misconceptions and Pitfalls
1.3 The Units of Measurement Students are amazed and horrified that NASA could lose an expensive spacecraft because of inconsistent units. Metric and SI units are unfamiliar to most Americans. That a nickel has a mass of 5 g and that a yard is nearly as long as a metre gives a good frame of reference. The practical examples of different temperatures on the Celsius scale (unnumbered figure) provide practical reference points. Several of the large SI unit prefixes (mega, giga, tera) are already familiar from memory capacity in computers. Conceptual Connection 1.2: Density The Chemistry and Medicine box on bone density provides an open‐ended conceptual question about designing an experiment to measure bone density; this may be good for a brief in‐class discussion.
1.4 The Reliability of a Measurement Use a 400‐mL beaker and a 100‐mL graduated cylinder to measure quantities of water. Make the point about the importance of estimating measurements. Add the quantities of water together and ask the students to calculate the final volume ... to the correct precision. Two tables present air quality data (with different precision) that might appear in a newspaper or other publication. Initiate a discussion of the certainty of digits in reported data. Water‐quality standards have evolved substantially since the advent of instrumental methods for quantitative analysis. Ask the question: Does zero mean that a particular analyte is not present? The number on a calculator display requires interpretation; only the user knows the certainty of the values entered. A discussion about why integrity in data reporting is particularly important in science is appropriate. It should point out that scientists report how they did the experiments so others can try to repeat and verify the work. Use recent examples from the media.
.
A common misconception is that 100 cm3 is equal to 1 m3. Some students initially are confused that density can be used as a conversion factor even when the units are inverted.
Students presume that calculators are flawless but forget that calculators do only what the user dictates.
7