What is the difference between a physical change and a chemical change?
A chemical change always happens on a molecular level while a physical one only concerns a state of matter. A chemical change forms a new substance when a physical change doesn't. You can go to http://www.chem4kids.com/files/matter_chemphys.html and http://chemistry.about.com/od/lecturenotesl3/a/chemphyschanges.htm for more details.
A chemical change changes the particles and a physical change only changes the apperance