Two sealed, transparent cubic containers—Sample X and Sample Y—each have the same…
CHEMISTRY · Multi-part · AP · Chemistry · Properties of Substances and Mixtures · Properties of Substances and Mixtures
Problem
Two sealed, transparent cubic containers—Sample X and Sample Y—each have the same total volume. A scientist provides particulate-level verbal descriptions of their contents at the same temperature and pressure:
• Sample X: "Within the cube, equal numbers of blue spheres and red cubes are distributed so that every region of space contains the same ratio of blue spheres to red cubes. No aggregation of like particles is observed."
• Sample Y: "Clusters of 30–50 blue spheres are dispersed in a continuous medium of red cubes. The clusters occupy distinct regions separated by regions that contain only red cubes."
Assume that blue spheres and red cubes represent chemically distinct substances that do not react under the stated conditions.
(a) Translate each particulate description into a concise macroscopic description suitable for use in a laboratory notebook.
(b) Classify each sample (X and Y) as a homogeneous mixture, a heterogeneous mixture, or not a mixture. Provide two specific pieces of evidence from the particulate description to support EACH classification.
(c) For Sample Y, propose one practical method to obtain a portion of matter that is enriched in blue spheres relative to the original sample. Explain how the method exploits the heterogeneous character of the sample.