It is a homogenous mixture because it cannot be separated by physical means. And also, it is even all over.
<span>The words you seek are soluble and insoluble.The chemical you want is an acid. Add an acid (acetic acid or hydrochloric acid) and the CaCO3 will fizz but CaCl2 will not</span>
Homogeneous:
denoting a process involving substances in the same phase (solid, liquid, or gaseous).
Herogeneous:
of or denoting a process involving substances in different phases (solid, liquid, or gaseous).