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Chapter 9 Compounds. Lesson 1 Notes. Vocabulary. 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. Combining Elements. Elements join together to create compounds.
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Chapter 9 Compounds Lesson 1 Notes
Vocabulary • 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.
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. H + O O H H H Liquid Gas Gas
Many 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)
Making and Breaking Compounds • To form or break a compound, a chemical REACTIONmust occur. • This will only happen if energy is added (most commonly in the form of heat).
How to Read a Chemical Formula • Each capital letter in a formula represents an element on the periodic table. H2ONaCl • The subset number tells you how many atoms of that element are in each molecule H2O Hydrogen Oxygen Chloride Sodium Two hydrogen
Let’s Practice What You Know! • Let’s look that the chemical formula Fe2O3 • How 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…. O H H
Everyday Compounds • Water is Earth’s most abundant element. • The earth is made up of 75% water • Your body is 66% water • You use compounds everyday. Here are some everyday compounds: Everyday Compounds