Chemical reactions come in 1000's of shapes and sizes! Chemists don't memorize them all... we learn to categorize them! The five main categories for chemical reactions are: Synthesis (put together), Decomposition (take apart), Single Replacement (an element replaces another that is bonded in a compound and kicks it out), Double Replacement (ions in two compounds switch partners) (Double Replacement includes most acid/base reactions) and Combustion (MEANS COMBINES WITH OXYGEN! NOT EXPLOSION). Today we did a bunch of "mini experiments" and chose a category for the chemical reaction. We also paid close attention to changes in energy. Reactions that need or absorb energy to happen are called "endothermic". Reactions that give off energy as a product are called "exothermic". We also discussed what a catalyst is and how it works. It is a good bet that the only thing we are going to remember about today is BURNING MAGNESIUM!