All GRE Subject Test: Chemistry Resources
Example Questions
Example Question #1 : Physical Chemistry
Which of the following reactions has a positive value for change in entropy ?
Possible Answers:
Water evaporates into water vapor
Water freezing into ice
A salt precipitates out of a saturated solution
Correct answer:
Water evaporates into water vapor
Explanation:
Entropy is a measure of the disorder of a system. In other words, when the components of a system become more uniform and spread out, the entropy of the system has increased. For example, when a liquid becomes gaseous, the molecules separate from one another, increasing the disorder of the system. As a result, the evaporation of water results in an increase in entropy.
All other options result in a more ordered system, which decreases entropy.
Dariush
Certified Tutor
Certified Tutor
University of New Orleans, Associates, Chemistry. University of New Orleans, PHD, Material Chemistry.
Andrew
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University of South Florida-Main Campus, Bachelors, Biomedical Sciences. New York Medical College, PHD, Doctor of Medicine.
All GRE Subject Test: Chemistry Resources
