Chemistry: A study of Matter and Energy
Chemistry: The
study of Matter, its composition, its properties, and the changes it undergoes.
Matter: Any substance that has mass.
Energy: the ability to do work
We will look at two Types of Energy in a later chapter. Be able to distinguish between these two types of energy.
Kinetic and Potential energy Example
Ions: Electricity in Motion and at Rest
Atoms: fundamental, invisible particles that make up all matter
Ion: an atom or a group of atoms that carries an electrical charge
Electroyte: a substance that conducts electricity when it is dissolved in water or when it is melted. Composed of ions in solution.
Elements and Compounds
Elements: A fundamental substance in which all atoms are the same.
Example:
Oxygen
Gold
Compounds: A pure substance made up of two or more elements combined in fixed proportions..
Example:
Water
Salt
Interactive Lesson:Learning the names and symbols of the Elements.
Scientific Method
The scientifc method is the process used by scientists to understand the universe.
Scientific Method:
Definitions:
Scientific Hypothesis: guesses that can be tested by experiment
Scientific Laws: Large amounts of scientific data summarized in a brief
statement.
Scientific Theories: Detailed explanations of the behavior of matter based
on experiments; may be revised if new data warrants.
Scientific Models: use of tangible items or pictures to represent invisible
processes.
The next three sections are not included in your text, but are essential concepts. I have included some interactive lessons to help prepare you for these sections.
States of Matter
I will refer to matter in different states . The three states of matter
are solid, liquid, and gas.
Solid - has definite shape and volume
Liquid - has definite volume and takes the shape of the container
Gas - takes the shape and volume of the container
Click on the boxes below and decide which is solid, liquid or gas.
Physical Vs. Chemical Properties
It is important for you to be able to distinguish properties of matter. Some of these properties are chemical in nature, and some are physical.
Chemical Properties - describe how one substance reacts with other substances.
Physical Properties - properties that can be observed and specified without reference to any other substance.
Interactive Lesson: Chemical vs. Physical Changes
Be sure this lesson has loaded completely before you try to click on next.
Since we have distinguished between elements and compounds, it is important to also distinguish between pure substances and mixtures. Pure substances and mixtures can be elements or compounds. The difference is that a pure substance must contain only one element or compound.
Pure Substances and Mixtures
Pure Substance: Matter with a definite or fixed composition.
Example:
Pure Water
Pure gold
Mixture: Matter with a variable composition (contains one or more pure substances).
Example:
Salt water
Tap water
Brass - mixture of gold and copper
Homogeneous Mixtures: a mixture that is the uniform throughout (often looks to be in same state).
Heterogeneous Mixtures: a mixture that is not uniform throughout (more than one state obviously present).
Interactive Lesson: Pure Substance and Mixtures
© Laura Maki - 1998