Signs of Chemical Change

One sign of a chemical change is a precipitate.  A precipitate is a solid that forms in a solution due to a chemical reaction.  A precipitate example is the formation of such a solid in the liquid.

Another sign that a chemical change has happened is if a gas is formed.  An example of this is when you put an antacid tablet containing a mixture of baking soda and citric acid in a glass of water. What comes out is bubbles of carbon dioxide gas.

Temperature increases are a sign of chemical change that releases energy.  This shows that the release of energy is a chemical change.

Color change is an example of chemical change.  When you spill food coloring on a shirt, you add some bleach to remove the color.  The bleach chemically takes away the color.  Also, metals change color when they tarnish.