Au lie 3. What are the two categories of pure substances?
a.
b.
I
C.
d.
e.
f.
g.
h.
i.
j.
k.
1.
b.
m.

Awhite powder is added to a solution. the images show observations made before the powder is added, just after the powder has been added, and a little while later. (the liquid in the small beaker is phenol red solution.) what evidence shows that a chemical change has taken place?