INTRODUCTORY CHEMISTRYINTRODUCTORY CHEMISTRYConcepts and Critical Thinking

Sixth Edition by Charles H. Corwin

Chapter 1 1© 2011 Pearson Education, Inc.

Chapter 1Introduction to

Chemistryby Christopher Hamaker

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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.

• 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.

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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.

• 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.

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Problem Solving, Continued

• Are we confining the problem?

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

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Chemistry: The Central Science

• Knowledge of chemistry is important to understanding the world around us.

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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.