Regents Chemistry Exam August 2022
41 Which two particle diagrams represent two different phases of the same compound, only?
(1) A and B
(2) A and C
(3) B and C
(4) B and D
Explanation: In a solid phase, the atoms or molecules are really close to one another with a fixed volume and shape. In a liquid phase, they are more spread out with a fixed volume but not fixed shaped. In a gas they are most spread out and don't have fixed volume or shape. The white circle represents an atom of one element and the black circle represents atom of a different element. We are asked to identify two different phases of the same compound. Choice A has two different compounds, one which two white circled and another with one white and white black. We can eliminate it. Choice C, likewise has two different compounds and can be eliminated. Choice B and D have one compound each (one black circle with one white circle). Choice D represents a solid phase since all the molecules are next to each other. Choice B represents a gaseous phase most likely since all the molecules are very spread out.