Chemical agent and Surface-active agent

Chemical agent noun - An agent that produces chemical reactions.

Surface-active agent and chemical agent are semantically related. In some cases you can replace phrase "Surface-active agent" with "Chemical agent", this phrases are similar.

Surface-active agent noun - A chemical agent capable of reducing the surface tension of a liquid in which it is dissolved.

Chemical agent and surface-active agent are semantically related. You can use "Chemical agent" instead a noun phrase "Surface-active agent".