A beaker initially contains a crystalline solid composed of alternating green and…
CHEMISTRY · Multi-part · AP · Chemistry · Properties of Substances and Mixtures · Properties of Substances and Mixtures
Problem
A beaker initially contains a crystalline solid composed of alternating green and purple spheres arrayed in a three-dimensional lattice. Water molecules, depicted as one large red sphere bonded to two smaller white spheres, are then added. A subsequent particulate sketch shows the green and purple spheres dispersed throughout the solution, each surrounded by several water molecules oriented with either the red or the white end facing the ion.
Consider the process that occurs when the solid is added to water and respond to the following.
(1) Describe in detail the changes in the spatial distribution and immediate environment of the green and purple spheres from the initial to the final sketch.
(2) Discuss whether the dissolution of the solid in water should be classified as a physical change, a chemical change, or both. Support your argument by citing specific interactions or bonds that are broken and formed.
(3) Design an experimental observation—macroscopic or microscopic—that would provide additional evidence to support your classification in part (b), and explain how the observation would be interpreted.