Mrs. Trotter’s 8th Grade Science Class Chemical Properties Mrs. Trotter’s 8th Grade Science Class

Chemical Properties The characteristics of a substance that describe what will happen when it interacts with other substances.

All Clues! Chemical Change A substance turns into one or more new substances that have DIFFERENT properties than the original substance. gas produced color changes light produced temperature changes All Clues!

Chemical Reactions Baking soda + vinegar= carbon dioxide + salty water reactants …. form…. products Baking soda + vinegar= carbon dioxide + salty water

Remember what elements are made of…? Atoms! The smallest particles that have the properties of an element are called atoms!

Inside Atoms Nucleus- holds protons & neutrons protons are positive Neutrons are neutral Outside the nucleus we find electrons -electrons are negative - they swirl around the nucleus like bees in on a hive!

Electron Cloud Model Electrons exist in fixed energy levels called electron shells the lowest level can contain 2 electrons the next level can hold up to eight electrons all together they can have 7 energy levels the highest level with electrons in it is called the outer shell

In chemical changes, protons and neutrons stay in the nucleus BUT! Electrons in the outer levels like to jump to or are shared with the outer shell of other electrons. When one or more electrons jump or shares with another atom BOOM! It becomes a compound!

the compound then has different properties than either of the original substances! GET IT???? A chemical change forms substances that are different than the original substances !!!!!!! !!!!!!!!!!!!!!!???????????????????????????????????????? right?!!

You end up what you start with Conservation of Mass There is no overall increase or decrease in the quantity of the matter that is changing. You end up what you start with

Types of Chemical Equations There are many types of chemical equations and impossible to memorize them all. Most reactions fit into one of four catergories that we will memorize. Synthesis Decomposition Replacement Combustion

Synthesis + Two or more substances combine and form one compound

Decomposition + + One compound breaks down and forms two or more substances

Single Replacement + + + + One element replaces another element in a compound

Double Replacement + + A chemical reaction in which a substance combines with oxygen and releases energy