Chapter 1 “Introduction to Chemistry” General Chemistry

Section 1.1 Chemistry OBJECTIVES: Identify five traditional areas of study in chemistry.

Section 1.1 Chemistry Relate pure chemistry to applied chemistry. OBJECTIVES: Relate pure chemistry to applied chemistry.

Section 1.1 Chemistry OBJECTIVES: Identify reasons to study chemistry.

What is Chemistry? Chemistry is the study of the composition of “matter” matter is anything with mass and occupies space, its composition, properties, and the changes it undergoes. Has a definite affect on everyday life -

Chemistry is the study of the composition, structure, and properties of matter and the changes it undergoes – such as burning fuels. C2H5OH + 3 O2  2 CO2 + 3 H2O + Energy Reactants  Products

5 Major Areas of Chemistry Analytical Chemistry- concerned with the composition of substances. Inorganic Chemistry- primarily deals with substances without carbon Organic Chemistry- essentially all substances containing carbon Biochemistry- Chemistry of living things Physical Chemistry- describes the behavior of chemicals (ex. stretching); involves lots of math! Boundaries not firm – they overlap and interact

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What is Chemistry? Pure chemistry- gathers knowledge for the sake of knowledge Applied Chemistry- is using chemistry to attain certain goals, in fields like medicine, agriculture, and manufacturing – leads to an application * Nylon – Figure 1.3, page 9 * Aspirin (C9H8O4) - to relieve pain * Use of TECHNOLOGY (benefit!)

Why Study Chemistry? Everyone and everything around us involves chemistry – explains our world What in the world isn’t Chemistry? Helps you make choices; helps make you a better informed citizen A possible career for your future Used to attain a specific goal What did we describe as “pure” and “applied” chemistry?

Section 1.3 Thinking Like a Scientist OBJECTIVES: Identify three steps in the scientific method.

The Scientific Method A logical approach to solving problems or answering questions. Starts with observation- noting and recording information and facts hypothesis- a proposed explanation for the observation; must be tested by an experiment

Steps in the Scientific Method 1. Observations (uses your senses) a) quantitative involves numbers = 95oF b) qualitative is word description = hot 2. Formulating hypotheses (ideas) - possible explanation for the observation, or “educated” guess 3. Performing experiments (the test) - gathers new information to help decide whether the hypothesis is valid

Scientific Method “controlled” experiment- designed to test the hypothesis only two possible answers: hypothesis is right hypothesis is wrong We gather data and observations by doing the experiment Modify hypothesis - repeat the cycle

Scientific Method We deal with variables, or factors that can change. Two types: 1) Manipulated variable (or independent variable) is the one that we change 2) Responding variable (or dependent variable) is the one observed during the experiment For results to be accepted, the experiment needs to always produce the same result

Outcomes over the long term… Theory (Model) - A set of well-tested hypotheses that give an overall explanation of some natural phenomenon – not able to be proved Natural Law (or Scientific Law) - The same observation applies to many different systems; summarizes results - an example would be: the Law of Conservation of Mass

Law vs. Theory A law summarizes what has happened. A theory (model) is an attempt to explain why it happened – this changes as new information is gathered.

- Page 22 Using your senses to obtain information The procedure that is used to test the hypothesis Hypothesis is a proposed explanation; should be based on previous knowledge; an “educated” guess Tells what happened A well-tested explanation for the observations; cannot be proven due to new discoveries

Introduction to Chemistry End of Chapter 1 Introduction to Chemistry