Question

If a reaction is exergonic, then which of these statements is true?

A) The reaction absorbs energy from the surroundings.
B) The reaction releases energy to the surroundings.
C) The reaction is at equilibrium.
D) The reaction does not involve energy changes.

Answer 1

An exergonic reaction releases energy to the surroundings, which makes statement B correct. Examples include cellular respiration and catabolic reactions, which are exergonic, whereas photosynthesis and anabolic reactions are endergonic.

Step-by-step explanation:

If a reaction is exergonic, then the statement that is true is: B) The reaction releases energy to the surroundings. Exergonic reactions are characterized by the release of energy, as they have a negative Gibbs free energy change (ΔG). This means that the products have less free energy than the reactants, making the reaction spontaneous and capable of performing work.

To further clarify with examples:

• Cellular respiration is an exergonic process because it releases energy that the cells can use for various activities.
• Photosynthesis, on the other hand, is endergonic as it requires the absorption of energy from sunlight to convert carbon dioxide and water into glucose.
• Catabolic reactions are generally exergonic because they break down molecules and release energy.
• Anabolic reactions are typically endergonic as they construct larger molecules from smaller ones, consuming energy in the process.

Activation energy is needed for both endergonic and exergonic reactions, though their energy profiles differ. Exergonic reactions have products with lower energy than the reactants while endergonic reactions have products with higher energy than the reactants.