Endothermic+and+Exothermic+Reactions

Chemical reactions always involve a change in energy. Energy is neither created nor destroyed. Energy is absorbed or released in chemical reactions. Chemical reactions can be described as endothermic or exothermic reactions. ** **    **//  Definitions:  //** Chemical reactions in which energy is absorbed are endothermic. Energy is required for the reaction to occur. The energy absorbed is often heat energy or electrical energy. Adding electrical energy to metal oxides can separate them into the pure metal and oxygen. Adding electrical energy to sodium chloride can cause the table salt to break into its original sodium and chlorine parts. // Chemical reactions in which energy is released are exothermic. The energy that is released was originally stored in the chemical bonds of the reactants. Often the heat given off causes the product(s) to feel hot. Any reaction that involves combustion (burning) is an exothermic chemical reaction. // C + D = Decrease in temperature //**// A chemical reaction that transfers energy from the reactants to the surroundings is referred to as exothermic
 * [[image:Presentation1.jpg width="223" height="167" align="right" caption="Did you ever wonder how this was possible?"]]ENERGY OF CHEMICAL REACTIONS**
 * // Endothermic Reactions  //**   //
 * //  Exothermic Reactions   //**//
 * // A + B = Increase in temperature

An endothermic reaction is one in which heat is transferred from the surroundings to the reactants.

Photosynthesis is an example of an endothermic chemical reaction in which plants use sunlight to make glucose and oxygen.

Bioluminescence is an exothermic reaction in which living things produce light. How To Create an Endothermic Chemical Reaction How To Create an Exothermic Chemical Reaction //