Chemical Reactions

What is a Chemical Reaction? Chemical Reaction - 2 or more substances undergo a chemical change that results in the formation of a new substance. Also known as a chemical change. What are the indicators of a chemical reaction? Evolution of Gas, Light, and/or Heat Color Change Formation of a Precipitate

Types of Chemical Reactions Endothermic Reaction – A chemical reaction where the energy or heat is absorbed and the external temperature goes down. Example: Baking Bread The heat is absorbed in the bread during the chemical reaction, and the oven is cooler because of it. http://www.youtube.com/watch?v=MyAzjSdc3Fc&fea ture=related

Types of Chemical Reactions Exothermic Reaction - A chemical reaction where the energy or heat is released and the external temperature goes up. Example: Campfire Heat is being released into the environment and you can feel the temperature go up around the fire. http://www.youtube.com/watch?v=YIfV2Z-4M5E

Chemical Reactions occur in either Open or Closed Systems Open System- A system that allows matter to enter from or escape to the surroundings. Closed System- A system that does not allow for matter to enter from or escape to the surroundings. Example: A chemical reaction taking place inside of a sealed, plastic bag.

Law of Conservation of Mass This law states that matter cannot be created nor destroyed. In a chemical reaction, the matter changes into new substances but the amount does not change.