1. Law of Conservation of Mass

2. The Law of Conservation of Mass (or Matter)
the mass stays the same during a physical change
the mass stays the same during a chemical change in a closed system
matter cannot be created or destroyed
the number of atoms remain the same before and after the change

3. Endothermic/Exothermic Processes & Reactions

4. Exothermic Endothermic Process Heat exiting a substance
Ex: water freezing
Physical change
Heat entering a substance
Ex: water evaporating
Reaction
Chemical reaction where energy is released in the form of light or heat
Feels hot – chemical bonds forming
Temp. change - warmer
Ex: Calcium & water
Chemical reaction that absorbs energy from its surroundings
Feels cold – chemical bonds breaking
Temp. change - colder
Ex: Vinegar & baking soda