Why does the glass seems to disappear in the oil?

When we see glass, we don't see the glass object itself but through other objects in the room are reflected/distorted by the glass. The glass disappeared because both Pyrex and vegetable oil bend (refract) light by the same amount – light travels straight through both materials!

part 1: which substance has a higher solubility?

a

smallest amount left undissolved atall temps in table shown most has dissolved high sol'by