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Chapter 1
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Chapter 1. Introduction to Chemistry
Chapter 1
Table of Contents
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1.1 Chemistry: An Introduction
1.2 What is Chemistry?
1.3 Solving Problems Using a Scientific Approach
1.4 The Scientific Method
1.5 Learning Chemistry
Section 1.1
Chemistry: An Introduction
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Why Is Chemistry Important?
Section 1.1
Chemistry: An Introduction
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Ice cubes in water (H2O) Graphite and Diamond (C)
Section 1.1
Chemistry: An Introduction
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New materials
New pharmaceuticals
New energy sources
Food supplies
Help the environment
Section 1.1
Chemistry: An Introduction
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CHLOROFLUOROCARBONS (CFCs)
Solve the problems…
Double-edged sword
Freon-12---noncorrosive nature and
ability to resist decomposition
Freon-12---destroy ozone (O3)in the upper
atmosphere.Free radical Cl + O3 O2 + ClO
Section 1.1
Chemistry: An Introduction
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In this course, you will:
• Learn the principles of chemistry.
• Become a better problem solver!
Section 1.1
Chemistry: An Introduction
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QUESTION
• Which of the following statements is false?
1. A knowledge of chemistry is useful to almost everyone.
2. The principles of chemistry are inherently neither good nor bad – it’s what we do with this knowledge that really matters.
3. A major by-product of studying chemistry is that you will become a better problem solver.
4. Chemical industries are the ones responsible for all our environmental problems today.
Section 1.1
Chemistry: An Introduction
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ANSWER
•Choice #4 is false. Although chemical industries have contributed to some environmental problems, they are not responsible for all of them. The industries that apply the chemical sciences are now determined to be part of the solution to our environmental ills rather than part of the problem.
•: Chemistry: An Introduction
Section 1.2
What Is Chemistry?
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• The science that deals with the materials of the universe and the changes these materials undergo. (Chemical changes)
• The central science. Understanding most other fields of science requires
an understanding of chemistry.
1.Wood burns in air, forming water, carbon dioxide and other substances.2. Eggs, flour, sugar and baker powder are mixed and baked to yield a cake.3. The definition of the term chemistry is learned and stored in the brain.
Section 1.3
Solving Problems Using a Scientific Approach
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1. Recognize the problem and state it clearly.
a) Making an observation.
Section 1.3
Solving Problems Using a Scientific Approach
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2. Propose possible solutions to the problem or possible explanations for the observation.
a) Formulating a hypothesis.
Section 1.3
Solving Problems Using a Scientific Approach
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3. Decide which of the solutions is the best or decide whether the explanation proposed is reasonable.
a) Performing an experiment.
Scientific thinking can help you in all parts of your life!
Section 1.4
The Scientific Method
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Steps in the Scientific Method• Process that lies at the
center of scientific inquiry.
• The difference between observations and theories.
• An observation is something is witnessed and can be recorded.
• A theory is an interpretation-a possible explanation of why nature behaves in a particular way.
• The difference between a Law and a theory.
• A law tells what happens• A theory (model) is our attempt
to explain why it happens.
Section 1.4
The Scientific Method
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QUESTION
• Which of the following statements is false?
1. A law is a summary of observed behavior. For example, studies of innumerable chemical changes have shown that the total mass of the materials involved is the same before and after the change.
2. A theory is an explanation of behavior – why nature behaves in a particular way.
3. If a theory is disproven, then all of the observations that support that theory must also be disproven.
4. A law tells what happens.
Section 1.4
The Scientific Method
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ANSWER
•Choice #3 is false. A theory can be wrong in its attempt to explain why a behavior occurs but that does not mean that the observed behavior in itself is also wrong.
•: The Scientific Method
Section 1.4
The Scientific Method
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Scientific Models
• Summarizes what happens.
Law
Theory (Model)• An attempt to explain why it happens.• Set of tested hypotheses that gives an overall
explanation of some natural phenomenon.
Hypothesis
• A possible explanation for an observation.
Section 1.5
Learning Chemistry
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• Learn the vocabulary.• Memorize important information.• Learn and practice processes.• Keep working and learning from your mistakes.• Ask questions!
Section 1.5
Learning Chemistry
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Prerequisite Science Skills
Section 1.5
Learning Chemistry
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2.1 Scientific Notation
2.2 Units
2.3 Measurements of Length, Volume, and Mass
2.4 Uncertainty in Measurement
2.5 Significant Figures
2.6 Problem Solving and Dimensional Analysis
2.7 Temperature Conversions: An Approach to Problem Solving
2.8 Density
Section 1.5
Learning Chemistry
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Measurement
• Quantitative observation.• Has 2 parts – number
and unit. Number tells
comparison. Unit tells scale.
Section 1.5
Learning Chemistry
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• Technique used to express very large or very small numbers.
• Expresses a number as a product of a number between 1 and 10 and the appropriate power of 10.
Section 1.5
Learning Chemistry
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This depends on the number of places the
decimal point is moved and in which
direction.
Section 1.5
Learning Chemistry
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Using Scientific Notation
• If the decimal point is moved to the left, the power of 10 is positive.
345 = 3.45 × 102
• If the decimal point is moved to the right, the power of 10 is negative.
0.0671 = 6.71 × 10–2
Section 1.5
Learning Chemistry
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Concept Check
Which of the following correctly expresses 7,882 in scientific notation?
a) 7.882 × 104
b) 788.2 × 103
c) 7.882 × 103
d) 7.882 × 10–3
Section 1.5
Learning Chemistry
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Concept Check
Which of the following correctly expresses 0.0000496 in scientific notation?
a) 4.96 × 10–5
b) 4.96 × 105
c) 4.96 × 10–7
d) 496 × 107
26
Section 1.5
Learning Chemistry
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Math Review
Section 1.5
Learning Chemistry
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Section 1.5
Learning Chemistry
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• Quantitative observation consisting of two parts. number unit : tell scale or standard is being used to
represent the results of the measurement.
Nature of Measurement
Measurement
• Examples 20 grams 70 miles/hour
Section 1.5
Learning Chemistry
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The Fundamental SI Units
Physical Quantity Name of Unit Abbreviation
Mass kilogram kg
Length meter m
Time second s
Temperature kelvin K
Electric current ampere A
Amount of substance mole mol
SI Units: the need for common units standards
Section 1.5
Learning Chemistry
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• Prefixes are used to change the size of the unit.
Prefixes Used in the SI System
Section 1.5
Learning Chemistry
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• Fundamental SI unit of length is the meter.
Length (SI unit: meter)
Section 1.5
Learning Chemistry
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Conversion between inch and cm:
1 inch = 2.54 cm
Section 1.5
Learning Chemistry
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Volume (SI unit: cubic meter, m3) • Measure of the amount
of 3-D space occupied by a substance.
• Commonly measure solid volume in cm3.
• 1 mL = 1 cm3
• 1 L = 1 dm3
Section 1.5
Learning Chemistry
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Graduated Cylinders mL“zero was at the bottom of the scale, with values increasing going up the cylinder. “
Buret, mL
Pipet, mL
a buret has zero at the top with values increasing
going down the scale.
0
Section 1.5
Learning Chemistry
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Mass (SI unit: kilogram, kg)
• Measure of the amount of matter present in an object.
• 1 kg = 2.2046 lbs• 1 lb = 453.59 g
Section 1.5
Learning Chemistry
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Triple beam balance Electronic balance
Analytical balance