Chapter 1 Introduction to Chemistry 1 Vanessa N. Prasad-Permaul CHM 1025 Valencia Community College.

Chapter 1

Introduction to

Chemistry

1

Vanessa N. Prasad-PermaulCHM 1025

Valencia Community College

Evolution of Chemistry The Greeks

believed in four basic elements:

1. Earth

2. Air

3. Fire

4. Water

All substances were combinations of these four basic elements.

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Scientific Investigations

Science is the methodical exploration of nature followed by a logical explanation of the observations.

Scientific investigation entails the following activities: Planning an investigation Carefully recording observations Gathering data Analyzing the results

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The Scientific Method

The scientific method is a systematic investigation of nature and requires proposing an explanation for the results of an experiment in the form of a general principle.

The initial, tentative proposal of a scientific principle is called a hypothesis.

After further investigation, the original hypothesis may be rejected, revised, or elevated to the status of a scientific principle.

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Applying the Scientific Method

Step 1: Perform a planned experiment, make observations, and record data.

Step 2: Analyze the data and propose a tentative hypothesis to explain the experimental observations.

Step 3: Conduct additional experiments to test the hypothesis. If the evidence supports the initial proposal, the hypothesis may become a theory.

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Applying the Scientific Method, Continued

After sufficient evidence, a hypothesis becomes a scientific theory.

A natural law is a measurable relationship.

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Critical Thinking: Reactions with Oxygen

What do burning wood, rusting iron, and exploding gasoline have in

common?

All three are examples of combustion.

Combustion is a chemical reaction of a substance with oxygen.

Rusting is a slow reaction, burning is a rapid reaction, and an explosion is an instantaneous reaction.

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Modern Chemistry

Chemistry is a science that studies the composition of matter and its properties.

Antoine Lavoisier (1743-1794) said to be the founder

Chemistry is divided into several branches: Organic chemistry is the study of

substances containing carbon. Inorganic chemistry is the study of all other

substances that don’t contain carbon. Biochemistry is the study of substances

derived from plants and animals.8

Learning Chemistry

Different people learn chemistry differently.

What do you see in the picture?

Some people see a vase on a dark background; some people see two faces.

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Problem Solving Connect the dots using only four straight lines.

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• Experiment until you find a solution.

• Did you have to use five straight lines?

• No matter which dot we start with, we still need five lines.

Problem Solving, Continued Are we confining the problem?

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• We need to go beyond the nine dots to answer the problem.

Chemistry: The Central Science Knowledge of chemistry is important

to understanding the world around us.

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Chapter Summary Science began with the ancient Chinese,

Egyptian and Greek civilization

Ancient chemistry is based on speculation

Modern chemistry is based on scientific method

Robert Boyle founded the scientific method

The major components of the scientific method is:

Experiment

Hypothesis

Scientific Theory

Natural Law13

Chapter Summary Scientists use the scientific method to

investigate the world around them.

Experiments lead to a hypothesis, which may lead to a scientific theory or a natural law.

Chemistry is a central science with many branches.

The impact of chemistry is felt in many aspects of our daily lives.

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EXAMPLE 1.1 Introduction to Chemistry

The principal difference is that modern chemistry is founded on the scientific method. Ancient chemistry was based on speculation, while modern chemistry is based on planned experiments and the analysis of data.

Solution

What is the difference between ancient chemistry and modern chemistry?

Answer: We can distinguish a theory from a law by asking the question, “Is the proposed statement measurable?” If we take measurements and verify a relationship by a mathematical equation, the statement is a law; if not, it is a theory.

What question can we ask to distinguishbetween a scientific theory and anatural law?

Practice Exercise

Which of the line segments in the image below

appears to be longer, AB or BC?

Concept Exercise

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The earliest concept of science began in the civilizations of which countries?

a. Austria, France, and Germany

b. China, Egypt, and Greece

c. England, Italy, and Sweden

d. United States, Canada, and Japan

EXERCISE 1.1

© 2011 Pearson Education, Inc.Chapter 1 19

Modern chemistry mainly differs from ancient chemistry in the

a. application of scientific method.

b. availability of laboratories.

c. number of known elements.

d. use of computers.

EXERCISE 1.2

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Which is not a component of the scientific method?

a. beliefb. experimentc. hypothesisd. scientific theory

EXERCISE 1.3

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Which component of the scientific method never changes?

a. experimentb. hypothesisc. natural lawd. scientific theory

EXERCISE 1.4

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Who is considered the founder of modern chemistry?

a. Bunsenb. Lavoisierc. Einsteind. Plato

EXERCISE 1.5