June 2017 NY Regents Chemistry Exam
41 Which particle diagram represents one substance in the gas phase?
Solution: Gases spread out and take the shape of the container. We can eliminate choices 2 and 4, since they represent a solid. According to the question we are looking for one substance only. One substance means either an element or a compound. Choice 1 has two different substances, one with two white circles and another with two black circles. Choice 3 has one substance only.
Answer: 3
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