Question

what type of reaction occurs without the addition of heat?
a. a spontaneous reaction
b. a nonspontaneous reaction
c. a reaction at equilibrium
d. an endothermic reaction

Explanation:

• Option A: A spontaneous reaction is one that occurs naturally without the need for external energy input (like adding heat) to proceed.
• Option B: A nonspontaneous reaction requires external energy (such as heat) to occur.
• Option C: A reaction at equilibrium has no net change in reactants and products, and it doesn't relate to whether heat is added or not for the reaction to occur.
• Option D: An endothermic reaction absorbs heat from the surroundings, but it may or may not require external heat addition to start (some endothermic reactions can be spontaneous, but the key here is about reactions that occur without added heat, and spontaneous is a better fit for the definition of occurring without external heat input).

Answer:

A. A spontaneous reaction