Chapter 1 Table of Contents Return to TOC Chapter 1. Introduction to Chemistry.

Chapter 1

Table of Contents

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Chapter 1. Introduction to Chemistry

Chapter 1

Table of Contents

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Copyright © Cengage Learning. All rights reserved

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


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Ice cubes in water (H2O) Graphite and Diamond (C)

Section 1.1


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New materials

New pharmaceuticals

New energy sources

Food supplies

Help the environment

Section 1.1


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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


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In this course, you will:

• Learn the principles of chemistry.

• Become a better problem solver!

Section 1.1


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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


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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


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2. Propose possible solutions to the problem or possible explanations for the observation.

a) Formulating a hypothesis.

Section 1.3


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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


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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


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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


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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

Chapter 1 Table of Contents Return to TOC Chapter 1. Introduction to Chemistry.

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Transcript of Chapter 1 Table of Contents Return to TOC Chapter 1. Introduction to Chemistry.