Discover: Reversible and Irreversible Changes

Most (but not all) chemical changes are irreversible. Usually, this is a good clue to tell if something has undergone a chemical change. First you must decide how to tell if a change is reversible or irreversible.

Reversible changes are changes in which you can do something to restore the substance back to the way it was originally. For example, making the sugar solution by dissolving sugar into water was a reversible change. You were able to form a crystal to separate the sugar and the water again. In fact, all the mixtures you made in the first section were reversible changes because you were able to separate them again. Changes of state such as freezing, melting, or boiling are also physical changes that can be reversed. Water that has been frozen can be melted into water again.

     

Chemical change is usually much more difficult to reverse. When a chemical reaction occurs, a new substance forms with properties that are different from the original substance.

Irreversible changes cannot be undone. There is no way to restore the substance to its original form. When you cook an egg, it cannot be made back into an uncooked egg. Any type of cooking is an irreversible change. Most chemical reactions are irreversible because the original substance has been changed into something completely different.

What is the difference between reversible and irreversible changes?

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