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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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