1. Energy is always transferred during a chemical reaction.
2. The conservation of energy means that energy cannot be created or destroyed, only transformed from one form to another or transferred between systems.
3. Energy is transferred in chemical reactions through the breaking and forming of chemical bonds, which involves absorbing or releasing energy as heat, light, or other forms.
4. Reactions that transfer energy to the surroundings are called exothermic reactions.
5. You know an exothermic reaction has taken place if the temperature of the surroundings increases, or if heat, light, or sound is released.
6. Chemical reactions that transfer energy from the surroundings to the reactants are called endothermic reactions.
7. Examples of exothermic reactions: combustion (burning wood), respiration in cells.
8. Examples of endothermic reactions: photosynthesis, melting ice.
9. Thermal decomposition means the breakdown of a single compound into two or more simpler substances when heated.
10. If a reaction gives out energy to the surroundings, the products have less stored chemical energy than the reactants.
11. Not every collision results in a reaction because particles must collide with sufficient energy (activation energy) and proper orientation for bonds to break and reform.
Parent Tip: Review the logic above to help your child master the concept of endothermic and exothermic worksheet.
