Chemical Reactions
Chemical and Physical
Key Vocabulary
Precipitate: cause (a substance) to be deposited in solid form from a solution.
Exothermic: (of a reaction or process) accompanied by the release of heat.
Endothermic: (of a reaction or process) accompanied by or requiring the absorption of heat.
Physical Reactions
Physical change occurs when molecules are rearranged, but not chemically changed down the the molecular level. EXAMPLES: Boiling water, weathering rocks, dicing potatoes.
Chemical Reactions
Chemical change occurs when a change changes the chemical makeup of a substance. It breaks the bonds between atoms. EXAMPLES: oxidation, burning gasoline, bread rising.
What They Have in Common
Both change the appearance of the object. They both cause changes. And they both occur after a reaction.