Exothermic and Endothermic Reactions It’s a give and take relationship!!!!

Every Reaction Involves Energy During a reaction…bonds absorb energy and break 2. New bonds form…energy released STEPS

Symbols In Chemical Reactions = Solid Formation = Gas Formation

Symbols In Chemical Reactions Heat Heat is given off Light Energy Energy Electrical Energy Thermal Energy

What Is A Chemical Reaction? Chemical Reaction: the process by which one or more substances undergo change to produce one or more different substances How To Identify A Chemical Reaction Has Occurred Or Is Happening 1. Gas Formation 2. Solid Formation 3. Color Change 4. Energy Change

Parts To A Chemical Reaction Reactants: starting materials of a chemical reaction 2.Products: substances formed Products Reactants C O2 CO2

What Do You Notice About All The Atoms? Chemical Reaction 2 Products 2Na Cl2 2NaCl Reactants *** What Do You Notice About All The Atoms?

Energy is in the products in an Exothermic Reaction Exothermic Reactions Chemical Reaction in which energy is released or removed 2 Na + Cl2  2 NaCl + Energy Energy is in the products in an Exothermic Reaction

Endothermic Reactions Chemical reaction in which energy is absorbed 6 CO2 + 6 H2O + Energy  C6H12O6 + 6 02 Energy is in the reactants in an Endothermic Reaction

Chemical Reactions Must Be Balanced!!!! It’s a Law!!!!!!!!!!! The Law Of Conservation Of Mass **Mass is neither created nor destroyed in ordinary chemical reactions