90 likes | 310 Views
A chemical change is when atoms rearrange and form one or more new substances. Chemical Change. Examples of Chemical Change. Examples of evidence that a chemical change has occurred are: A change in temperature; Formation of a gas Change in color Light is given off
E N D
A chemical change is when atoms rearrange and form one or more new substances. Chemical Change
Examples of Chemical Change • Examples of evidence that a chemical change has occurred are: • A change in temperature; • Formation of a gas • Change in color • Light is given off • A CHEMICAL CHANGE (usually) CANNOT BE REVERSED!
Proof of Chemical Change • When paper is burned, the new substances produced are ash, carbon dioxide and water. The ash, carbon dioxide, and water cannot be recombined to make the paper again. • Evidence that a chemical reaction has occurred is the heat and light given off during the reaction.
Physical Change • In a physical change substances retain its original properties. • In other words, a physical change is any change in the size, shape, or the state of matter in which the identity of the substance is unchanged. The appearance of the substance may change, but the identity of the substance does not change.
Examples of Physical Change • A change in size, example: shredded paper • A change in shape, example: molding clay • A change in state, example:solid to liquid, liquid to solid, liquid to gas. • Dissolving a substance, into another substance to form a solution, example:sugar and water.
Proof • Mixing sugar and water may appear to be a chemical reaction, however, when you allow the water to go through a physical change, (evaporation) then the sugar returns to its crystallized form.
Types of Reactions • Synthesis reaction • Decomposition reaction • Single-replacement reaction • Double-replacement reaction • Combustion reaction • http://youtu.be/66kuhJkQCVM
Synthesis Reaction • http://player.discoveryeducation.com/index.cfm?guidAssetId=373BFC67-1589-46B0-9E45-8E6EA5304C91 • http://listverse.com/2008/03/04/top-10-amazing-chemical-reactions/
Now do your own research • Go to Google and ask the questions you need answers to pertaining to the experiments yesterday.