Signs of Chemical Change

1. Gas and Bubbles Gas released Not boiling

2. Color Change Color changes from one to another

3.Temperature Change Exothermic: heat is released. Temperature rises – hot. Exo- Out Example: combustion.

3.Temperature Change Endothermic: heat is absorbed. Temperature drops -cools Endo -In Example:

4. Precipitate Two liquids come together to form a semi-solid substance.

5. New Product New arrangement of the atoms. A new products is present that was not there before. New properties

Law of Conservation of Mass In 1789 Antoine Lavoisier discover that mass is neither created nor destroyed in chemical reactions. In a chemical reaction the total mass of the reactants is always equal to the total mass of the products.