CHEM101: General Chemistry I

In chemistry, we often study changes in matter. Two types of changes can occur in matter: physical and chemical.

To determine whether you are dealing with a physical or chemical change, ask yourself if you can reverse the process to recover the original material. Physical changes can be reversed, but chemical changes generally cannot. For example, ice melting is a physical change because you can re-freeze the water. However, cooking a steak is a chemical change because you cannot recover the raw meat. Note that we discuss the energetics of chemical change more thoroughly in Unit 6.

Watch this video to see examples of physical and chemical changes, and how we can observe a change to classify it.