Saturday, August 31, 2013

Physical and Chemical Changes

Changes around us

Physical and Chemical Changes
video

Terms

Definitions

Physical Properties
  • A characteristic of a pure substance that can be observed without changing it into another substance, any characteristic of a material that you can observe without it changing the identity of the substances that make up the material.
  • Includes color, shape, mass, Length, Volume, and densty
Physical ChangesIn this change the properties of a substance change, but the identity of the substance does not.
Chemical PropertiesAny characteristic that gives a substance the ability to undergo a change that results in a new substance.
Chemical Changes
  • A change in the identity of a substance due to the chemical properties of that substance
  •  A new substance or substances are formed as a result of such a change.
  • Something that can't be reversed.
Difference Between Chemical and Physical Properties
  • A physical property is any aspect of substance that can be measured or perceived without changing it. 
  • A chemical property, on the other hand, can only be observed by changing a substance's chemical identity.

  • . A physical change is reversible, a chemical change is not. For example, the freezing of water would be a physical change because it can be reversed,
  • whereas the burning of wood is a chemical change - you can't 'unburn' it