Everyday Examples
Believe it or not, compounds are all around us. Simply turn on your faucet and water will come pouring out. Water's chemical formula is H2 O, which means there are two hydrogen atoms bonded to one oxygen atom. So, is water a compound? Let's run down the checklist: Are there two different types of elements in water? Yes! Hydrogen and oxygen. Therefore, water is a compound.
Ready for another one? Alright, look at your kitchen table and find the salt shaker. Table salt's chemical name is sodium chloride and is represented in formula form as NaCl. There is one atom of sodium (Na) chemically bonded to one atom of chloride (Cl). Again, we have two different elements joined together, and thus table salt is considered a compound.
You are doing great. Take a big breath in, and exhale it. Okay, so you just blew a compound out of your mouth! The air that comes out of your mouth when you exhale contains carbon dioxide, and carbon dioxide's chemical formula is CO2 because there is one carbon atom bonded to two oxygen atoms. Because carbon dioxide is made up of two different types of elements, carbon and oxygen, it is considered a compound.
Okay, last example, and it's tricky! When you breathed in, your lungs were filled with oxygen. Oxygen's chemical formula is O2 because one atom of oxygen is bonded to another atom of oxygen. Is this a compound? No, oxygen is not a compound. There are two elements chemically bonded together, but they are the same type of element. Therefore, the oxygen we inhale would be considered a molecule.
Umbrella Term
The reason the terms molecules and compounds are especially confusing is because one includes the other. For you see, all compounds are molecules, but not all molecules are compounds.
This sounds complicated, but let's replace these words with something more familiar and see if it doesn't become clear. All apples are fruit, but not all fruits are apples. This makes sense right? If I showed you a grape and asked 'Is this a fruit?' you'd say 'Yeah,' even though it's not an apple.
It's the same for compounds and molecules. A compound is a specific type of molecule. Is sodium chloride (NaCl) a molecule? Yes. Is it a compound? Yes. Is oxygen (O2) a molecule? Yes. Is it a compound? No.
Lesson Summary
In summary, a molecule is when two or more elements are chemically bonded together, meaning they are two of the same kind. But a compound is when two or more DIFFERENT types of elements are chemically bonded together. So start exploring your environment and see how many compounds you can discover!
