1. Chapter 9 Compounds
Lesson 1 Notes

2. 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.

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. H O
Gas
Liquid +
I tr

4. 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)

5. Making 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).

6. How to Read a Chemical Formula
Each capital letter in a formula represents an element on the periodic table.
H2O NaCl
The subset number tells you how many atoms of that element are in each molecule H2O
Hydrogen
Oxygen
Sodium
Chloride
Two hydrogen

7. 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…. H O

8. Everyday Compounds 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