Energy and Reactions In a chemical reaction bonds

Energy and Reactions • In a chemical reaction bonds are either formed or broken • Bonds are a form of energy • All reactions result in either the absorption or release of energy

Exergonic Reactions • What are some words that begin with ex? • What does ex mean? • out of, from, out • Exergonic reaction is the release of or (exit) of energy in the form of heat or light

Triboluminescence - A type of exergonic reaction • Light that results from scratching or abrading a substance as when two pieces of quartz are rubbed together to produce light. • Another example the wintergreen lifesaver

Chemiluminescence-A type of exergonic reaction • Chemiluminescence is the production of light by a chemical reaction during which chemical energy is converted to light energy. • An example are light sticks

Bioluminescence • Bioluminescence is the production and emission of light caused by chemical reactions in living things

Bioluminescence • Bioluminescence can be used for camoflague, attraction, repulsion, and communication.

Jellyfish

Sea Slug (Phyllirhoe)

Firefly

Fireflies

Phosphorescence • Energy from an external source is absorbed • Glow in the dark stars, stickers, etc. • Phosphorescent substances have the ability to store up light and release it gradually.

Exothermic reaction • Exothermic reactions - release thermal energy. • Heat is exiting the reaction, therefore it feels warm/hot to the touch

Endergonic Reaction • Endergonic reaction - absorbs energy in the form of heat, light, or electricity • Energy enters the reaction • Endothermic reaction - A type of endergonic reaction. Heat needs to be added to the reaction. Heat enters the reaction. Sometimes feels cool/cold to us.