A pure substance is a sample of matter that is so pure that it can not be broken down into anything simpler without the aid of chemical change.

8/17/98 - Solids

A solid is a rather dense and hard state of matter. It's molecules are packed together like sardines, and usually in regular and repeating patterns. The molecules vibrate around fixed positions.

8/18/98 - Weight

It's not just what you see on your scale anymore. Weight is in actuality relative to the gravitational forces that you have acting upon you. Weight is calculated with the formula W=mg where m is your mass and g is acceleration due to gravity. On earth the acceleration due to gravity is 9.8m/sec²

8/19/98 - Joules

Ah yes, jewels, always beautiful, always a sign of status. Oh wait, not that kind. We are talking about a Joule here. In chemistry, a joule is mechanical energy. It is the amount of energy to move a mass of one kilogram from rest over a distance of one meter in one second.

8/20/98 - Dalton's Atomic Theory

John Dalton, and English schoolteacher, postulated these three laws.
1. All matter is composed of atoms that can neither be created or destroyed.
2. Atoms of one element are identical in size shape and mass, and these are the properties that atoms of other elements differ in.
3. A chemical reaction is simply the union or seperation of atoms.

8/21/98 - Ionic or Molecular

Here are a few tips in distinguishing molecular compounds from ionic compounds. Molecular compounds have much lower melting and boiling temperatures. Many of these compounds are actually liquids or gases at room temperature. Another way is by their electrical conductivity. Covalent molecular compounds are horrible at conducting electricity.

8/22/98 - The Most Abundant Element

I guess you could call this one the ballhog of the chemical world. This element is the most plentiful in the entire universe. What is it? Hydrogen.