Molecule vs Compound: Explanation and Practice

What is the Difference Between a Molecule and a Compound?

To some degree it's sort of a silly distinction but chemistry is that way sometimes. To be brief:

Molecules are made when two or more of any elements are joined together chemically.
For example H2, O2, and O3.

Compounds are made up of different types of atoms joined together chemically.
For example, CaCl2 or NaBr.

Here's why it's confusing. All compounds are also molecules. That's because our definition states that if there are two or more atoms combined chemically it's a molecule. (For example, O2, NaCl, PCl3.) If the individual atoms are different then it's also called a compound. (Such as NaCl, PCl3, but not O2.)

Summary: If there are two or more different atoms, it's both a molecule and a compound. If there are two or more of one kind of atom, it's just a molecule.

Molecule vs. Compound: Practice

The only way to really get this is to practice. Otherwise it's all just a bunch of words. Below is a Flash quiz about the difference between molecules and compounds with ten questions. If you can pass the quiz you probably can tell the difference between molecules and compounds on a school quiz or test.

That's it for the Molecule vs Compound quiz. You should be all set. Return to Success in Chemistry for more chemistry practice.