2Vocabulary Chemical Formula – a shorthand way to describe a compound. Chemical Reaction – process in which one or more substances are changed into one or more DIFFERENT substances.
3+ Combining Elements Elements join together to create compounds. Compounds usually have different properties from the elements that make them up. For example:Water is created by chemically joining two gasses.HOGasLiquid+I tr
4Many Compounds Are found in nature Others are created in a laboratory Some compounds are made up of just two compounds and others are made up of several.For example:CO2 = Carbon (C) and Oxygen (O)CaCO3 = Calcium (Ca), Carbon (C), and Oxygen (O)
5Making and Breaking Compounds To form or break a compound, a chemical REACTION must occur.This will only happen if energy is added (most commonly in the form of heat).
6How to Read a Chemical Formula Each capital letter in a formula represents an element on the periodic table.H2O NaClThe subset number tells you how many atoms of that element are in each molecule H2OHydrogenOxygenSodiumChlorideTwo hydrogen
7Let’s Practice What You Know! Let’s look that the chemical formula Fe2O3How many atoms of Iron are there? Oxygen?Write the chemical formula for the molecule you see here:What do you know about the chemical formula for sodium bicarbonate NaHCO3?Think…Do I know the elements, number of each, number of total atoms….HO
8Everyday Compounds Everyday Compounds Water is Earth’s most abundant element.The earth is made up of 75% waterYour body is 66% waterYou use compounds everyday. Here are some everyday compounds:EverydayCompounds