"Classify the following as 1) a heterogeneous mixture, 2) heterogeneous, but not a mixture, 3) homogeneous mixture, or 4) homogeneous, but not a mixture.
(a) an undissolved sugar cube in water
(b) a partially dissolved sugar cube in water
(c) a completely dissolved sugar cube in water
(d) an ice cube in water
The book's answers:
a an undissolved sugar cube in water= heterogeneous mixture
b a partially dissolved sugar cube in water= heterogeneous mixture
c a completely dissolved sugar cube in water= homogeneous mixture
d an ice cube in water= heterogeneous mixture. PROBLEM
My answer: d = heterogeneous, but not a mixture.
The book (Intro. to Chemical Principles, Stoker) states that "A heterogeneous mixture contains two or more visually distinguishable phases..." p. 92
It also states: "A mixture is a physical combination of two or more substances."
So, an ice cube in water cannot be a mixture according to the book's own definition, since water and ice are the same substance.
Can anyone explain who is right here?