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Introduction to Chemistry

Topic 1.1 What is Chemistry?

Topic 1.2 Matter

Topic 1.3 Scientific Methods

Section 1.4 Scientific Research

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Section 1.1 Matter and Chemistry

Chemistry

Matter

Substance

Macroscopic

Microscopic

Submicroscopic

mass

weight

Model

• Define substance.

• Explain what Chemistry is.

• Compare and contrast mass and weight.

• Explain why chemists are interested in a submicroscopic description of matter.

Chemistry is the study of everything around us.

Why Study Chemistry?

• All the “stuff” in the universe is made from building blocks that have been here since the beginning of the universe.

• These building blocks and everything made from them are called matter.• Those original pieces of matter are still here.

• Chemistry is the study of matter and the changes it undergoes.• Everything around you involves Chemistry

What is a substance?

• A substance is another name for a chemical• It is matter that has a definite composition.

• We will usually talk about PURE substances.

• 2 types of Pure substances–

• elements

• compounds

• Mixtures are not pure substances

Where do we find Chemical reactions?

• EVERYWHERE!• Most changes around you are the result of

chemical reactions.

• EVERYTHING that happens in your body is a chemical reaction or an energy change.

• Later we will learn how to tell if something is a chemical reaction

Matter and its Characteristics

• Matter has many different forms.

• Mass is a measurement that reflects the amount of matter.

• Depends on the number of particles

• Weight is a measure of mass and the force of gravity on an object.

• Weight can change from place to place, but mass is constant.

Matter and its Characteristics (cont.)

• Much of matter and its behavior is macroscopic, meaning that it can be observed without a microscope.

• Microscopic observations requires a light microscope – like looking at cells

• The structure, composition, and behavior of all matter can also be described on the submicroscopic (atomic) level.

• An understanding of the SUBmicroscopic level can help explain and predict behavior of matter

• Chemistry explains events on the atomic (submicroscopic) level that cause macroscopic observations.

• A model is a verbal, visual, or mathematical explanation of experimental data.

• Models are used to explain things that cannot be observed directly

• Since we can’t see things on a sub-microscopic level, we need models.• Models often change as our understanding

changes.

Matter and its Characteristics (cont.)

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