For a chemical reaction the activation energy for the forward reaction is +155kJ, and the backward reaction is +171kJ. What is the overall energy for the forward reaction?

1 Answer
Al E.
Feb 19, 2018

This question requires you to visualize the coordinate diagram and do a simple calculation.

If the reverse #E_a# is greater than the forward #E_a# (assuming this only has one transition state), then #DeltaG<0# and in most cases #DeltaH<0#.

butane.chem.uiuc.edu

We can take #DeltaE + E_"act"# to be the reverse #E_a# if you're confused by the seeming contradiction. I wanted to make it easier to visualize because this is confusing at first.

Hence,

#155"kJ" - 171"kJ" approx -16"kJ" = DeltaG_"rxn"#

is the overall energy of the reaction.

Related questions
Impact of this question
1132 views around the world
You can reuse this answer
Creative Commons License