Question

what happens during all chemical changes

Answer 1

there are different ways to identify when there's a chemical reaction that is taking place.
color change
energy absorption or release
odor change
production of gases or solids (precipitates)

Answer 2

science happens.

Answer 3

Molecular bonds are broken and different molecules are formed

Answer 4

During a chemical reaction, the reactants (starting chemicals) interact when they are brought together. Sometimes other conditions are needed (heat, a catalyst, etc) and sometimes the reaction will be spontaneous.

During the reaction, the chemical bonds of one or more of the reactants. change and are reconfigured/combined with atoms or parts of other molecules from other reagents and form new product chemicals. All of the atoms of the reactants are preserved in the products, just in the form of different reaction product compounds. Heat may also be consumed or generated by the reaction. The products likely have different properties than the reactants.

I know it's Wikipedia, but this actually explicates it very well.
http://en.wikipedia.org/wiki/Chemical_reaction

Answer 5

if you all want to be fancy like that then I shall say that the amount of energy in the universe remains the same. nothing is created nor destroyed.

Answer 6

Lol(: