The activation energy of a reaction going on its own is 20 kJ. If the reaction was treated with a catalyst, which would most likely represent the amount of energy needed to start a reaction?

Question

15 kJ
20 kJ
25 kJ
30 kJ

Answer 1

A catalyst works by lowering the activation energy required for a reaction to occur. If the activation energy of the uncatalyzed reaction is 20 kJ, the addition of a catalyst would likely reduce the activation energy. Therefore, the amount of energy needed to start the reaction with a catalyst would be less than 20 kJ.

Among the options provided:

• 15 kJ is less than 20 kJ
• 20 kJ is the same as the uncatalyzed reaction
• 25 kJ and 30 kJ are greater than 20 kJ

The most likely answer for the amount of energy needed to start the reaction with a catalyst would be 15 kJ.