In an endothermic chemical reaction, from where does the system obtain the heat energy required for the reaction to occur?

• A. From the surrounding environment
• B. From the chemical bonds breaking in the system
• C. From the reactants themselves
• D. From the products formed

Answer: (A)

Verified step by step guidance

1. Understand the definition of an endothermic reaction: it is a reaction that absorbs heat energy from its surroundings during the process.
2. Recall that in an endothermic reaction, the system requires energy input to break bonds or to proceed, which means the system gains heat rather than releasing it.
3. Recognize that the heat energy absorbed by the system must come from an external source, which is typically the surrounding environment.
4. Eliminate incorrect options: the energy does not come from the chemical bonds breaking within the system itself, nor from the reactants or products directly, but from outside the system.
5. Conclude that the system obtains the heat energy required for the reaction from the surrounding environment.