Which statement describes characteristics of an endothermic reaction?
Correct answer: B. The sign of ΔH is positive, and the products have more potential energy than the reactants.
- A. The sign of ΔH is positive, and the products have less potential energy than the reactants.
- B. The sign of ΔH is positive, and the products have more potential energy than the reactants.
- C. The sign of ΔH is negative, and the products have less potential energy than the reactants.
- D. The sign of ΔH is negative, and the products have more potential energy than the reactants.
Explanation
In an endothermic reaction, energy is absorbed from the surroundings, which means the enthalpy change (ΔH) is positive. This absorption results in the products having more potential energy than the reactants, as the system has gained energy. Option B correctly describes these characteristics. Options A, C, and D are incorrect because they either describe an exothermic process (negative ΔH) or incorrectly associate potential energy changes with the wrong sign of ΔH.
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About Thermochemistry and Energetics of Chemical Reactions
Thermochemistry measures energy changes in chemical reactions and distinguishes exothermic from endothermic processes. Work covers systems, surroundings and state functions, internal energy, the first law of thermodynamics, enthalpy and Hess's law, including the sign conventions used when heat enters or leaves a system.
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