[Campbell Biology P.199] Glow-in-the-dark necklaces emit light after being "activated" by sn... | Practice Question

Glow-in-the-dark necklaces emit light after being "activated" by snapping, which allows two chemicals to react. This process is called chemiluminescence. Given that light energy is emitted during this reaction, how would you classify this reaction?

  • A: Endergonic, because it requires an initial "activation" (snapping).
  • B: Exergonic, because it releases free energy in the form of light.
  • C: Both exergonic and endergonic, depending on the specific chemicals involved.
  • D: Neither, as light emission is not directly related to free energy changes.

Explanation

Chemiluminescence is a process where a chemical reaction emits light. The emission of light is a form of energy release. Reactions that release free energy are defined as exergonic. Therefore, the chemiluminescent reaction is exergonic, as it involves a net decrease in free energy.