PSAT Reading Question 486: Answer and Explanation

Question: 486

As used in lines 12–13, the phrase "thermodynamically favorable" most closely refers to a reaction in which

• A. the reactants are exclusively biological.
• B. a subject consciously chooses to undergo the process because of its positive effects.
• C. the reactants have more energy than the products.
• D. the products have more energy than the reactants.

Correct Answer: C

Explanation:

(C) This paragraph describes the process by which adenosine triphosphate undergoes a thermodynamically favorable process to form adenosine and inorganic phosphate and to release free energy. If energy is released in the reaction, it means that energy was being stored in the reactants, so the reactants have more energy than the products, choice (C). Choices (A) and (B) are incorrect because this term refers to an energy differential. Choice (D) is backward.