Question

A pure substance containing only one kind of what?

Answer 1

Only one kind of matter. Obtaining 100% is very difficult, time consuming, and consuming.

Answer 2

A pure substance containing only one kind of ATOM. An element is always uniform all the way through (homogeneous). An element CANNOT be separated into simpler materials (except during nuclear reactions). Over 100 existing elements are listed and classified on the PERIODIC TABLE.