Question

which is the best definition of activation energy? the energy required to end a chemical reaction the energy required to bind a substrate to an active site the energy required to form or break the bonds of reactant molecules the energy required to re - form bonds in product molecules

Explanation:

To determine the best definition of activation energy, we analyze each option:

• Option 1: Activation energy is not for ending a reaction, so this is incorrect.
• Option 2: Binding a substrate to an active site is related to enzyme - substrate interaction, not activation energy, so this is wrong.
• Option 3: Activation energy is the minimum energy that reactant molecules must possess to undergo a chemical reaction, which involves forming or breaking bonds of reactant molecules. This matches the definition of activation energy.
• Option 4: Re - forming bonds in product molecules is part of the reaction process after the activation energy barrier is overcome, not the definition of activation energy.

Answer:

the energy required to form or break the bonds of reactant molecules