Consider the figure below, in which the blue circles represent atoms of copper metal (atomic mass 63.5 amu), while the red circles represent atoms of zinc metal (atomic mass 65.4 amu).
Here are four statements concerning this system.
Which of the following CORRECTLY describe the system?
I. This is a single-phase mixture with a copper-to-zinc atom ratio of 4:1.
II. This is a two-phase mixture with a copper-to-zinc atom ratio of 4:1.
III. The mixture is 75% copper, by mass.
IV. This mixture could be an alloy of copper and zinc.