Question

define plastic. How are they different from other compounds

Answer 1

Plastic is material consisting of any of a wide range of synthetic or semi-synthetic organic compounds that are malleable and so can be molded into solid objects.
They are different from other compounds as These compounds contain atoms such as oxygen, nitrogen, or sulfur in their backbone chains, in addition to carbon.

Answer 2

a synthetic material made from a wide range of organic polymers such as polyethylene, PVC, nylon, etc., that can be moulded into shape while soft, and then set into a rigid or slightly elastic form.