Chemical substance and Restrainer

Chemical substance noun - Material produced by or used in a reaction involving changes in atoms or molecules.

Restrainer and chemical substance are semantically related. In some cases you can replace term "Restrainer" with "Chemical substance", this terms are similar.

Restrainer noun - A chemical that is added to a photographic developer in order to retard development and reduce the amount of fog on a film.

Chemical substance and restrainer are semantically related. Sometimes you can use "Chemical substance" instead a noun "Restrainer".