1. INTRODUCTORY CHEMISTRY INTRODUCTORY CHEMISTRY Concepts and Critical Thinking Seventh Edition by Charles H. Corwin Chapter 1 Lecture © 2014 Pearson Education, Inc. Chapter 1 Introduction to Chemistry By: Abdirashid Adam Isak (M.Sc.) Somali National University

2. Chapter 1 © 2014 Pearson Education, Inc. Evolution of Chemistry The Greeks believed in four basic elements: 1. Air 2.Fire 3.Water 4.Earth All substances were combinations of these four basic elements.

3. Chapter 1 © 2014 Pearson Education, Inc. The Scientific Method Science is the methodical exploration of nature followed by a logical explanation of the observations. An experiment involves scientists who explore nature according to a planned strategy and make observations under controlled conditions.

4. Chapter 1 © 2014 Pearson Education, Inc. The Scientific Method, Continued 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.

5. Chapter 1 © 2014 Pearson Education, Inc. 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 scientific theory.

6. Chapter 1 © 2014 Pearson Education, Inc. Applying the Scientific Method, Continued After sufficient evidence, a hypothesis becomes a scientific theory. A natural law states a measurable relationship.

7. Chapter 1 © 2014 Pearson Education, Inc. 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. –Green chemistry is the design of chemical processes that reduce waste and hazardous substances

8. Chapter 1 © 2014 Pearson Education, Inc. Chemistry Connection: “Worth Your Salt?” Salt was once so valuable, it was used to pay Roman soldiers Table salt is obtained by three major processes: –Salt Mining –Solution Mining –Solar Evaporation of Salt Water Table salt is necessary for the human body, but too much can cause high blood pressure

9. Chapter 1 © 2014 Pearson Education, Inc. 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.

10. Chapter 1 © 2014 Pearson Education, Inc. Problem Solving Connect the dots using only four straight lines. Experiment until you find a solution.

11. Chapter 1 © 2014 Pearson Education, Inc. Problem Solving, Continued 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.

12. Chapter 1 © 2014 Pearson Education, Inc. Problem Solving, Continued Are we confining the problem? We need to go beyond the nine dots to answer the problem.

13. Chapter 1 © 2014 Pearson Education, Inc. Chemistry: The Central Science Knowledge of chemistry is important to understanding the world around us.

14. Chapter 1 © 2014 Pearson Education, Inc. Chemistry Connection: A Student Success In 1886, pure aluminum metal cost over $100,000 per pound. Charles Hall and Paul Héroult both independently discovered a method for obtaining pure aluminum from aluminum ore. The industrial process for obtaining aluminum metal is referred to as the Hall-Héroult process. Today, pure aluminum costs less than $1 per pound.

15. Chapter 1 © 2014 Pearson Education, Inc. 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.