Chem Class- September 28, 2009

Here we are now in Unit 2: Properties of Matter. Today in class, we took notes on matter and then watched a video (part of a MythBusters episode), trying to see how many chemical and phyiscal changes we could spot.
So just what is matter?

MATTER

- Anything that has mass and occupies space

- It can exist in many different states but the most common are: Solid,Liquid,Gas,Plasma,Aqueous,Amorphous

Solid: Holds one shape and has a definite volume
Liquid: Can change shape, but has a definite volume
Gas: Can change shape and colume
Aqueous: Something dissolved in water

In this picture, we see that solids have strong bonds, liquids have weak bonds, gases have no bonds and plasma involves ionization:

- Can undergo many changes: Physical, Chemical and Nuclear

 Physical Changes: Involves changing shape or state of matter and no new substances are formed
(Examples: Crushing, tearing, boiling water, cutting wood, smashing cars)
Changing from a solid to a gas can often be confused as a chemical change but remember that if that chemicals remain the same it is a chemical change.

Chemical Changes: Properties of matter change and new substances are formed
(Examples: Conductivity, acidity, colour, iron rusting, burning wood, digesting food)

So remember: Changes of state are considered phsical changes:

Also, during the melting process, chemicals usually follow this path:

New substances are formed in a chemical change:

One last point before we are through: In physical and chemical changes, matter is neither created or destroyed. This is known as: Conservation of Matter. The French chemist Antoine-Laurent Lavoisier is considered to have discovered this concept.