2. Energy and Chemical Reactions

3. An explosion results from a rapid chemical reaction. * energy is either released or absorbed in all chemical reaction

4. The energy of a chemical reaction can take many forms. * heat * light * sound * motion * electricity

5. To break a chemical bond, energy must be provided. * energy added to the reaction

6. To form bonds, energy is released. * energy is given off during the reaction

7. Exothermic Reactions Some form of energy is given off by the reaction. * more energy is released than needed to form new bonds * may cause it to feel hot

8. Examples of exothermic reactions Glow Sticks Thermacare Heat patches Icy Hot cream

9. Endothermic Reactions Energy must be provided for the reaction to take place. * more energy is required to break bonds than needed to form new bonds

10. Example of Endothermic Reactions Injury Gel packs Cooking

11. An endothermic reaction is frequently used to obtain a metal from its ore. * sometimes thermal energy is used * sometimes electrical energy is used

12. Catalyst A substance that speeds up a chemical reaction without being permanently changed. * needed because some reactions are too slow to be useful

13. Certain proteins known as ENZYMES act as catalysts in living organisms. * without them, life as we know it would not be possible

14. Inhibitors Used to combine with one of the reactants. * used to prevent certain reactions from occurring

15. BHT and BHA are inhibitors. * they prevent the spoilage of certain foods

16. Using catalysts and inhibitors are just a few of the ways scientists control chemical reactions.