Page 1 of 1

Drawing/Labeling reaction profile

Posted: Mon Mar 06, 2017 1:16 pm
by Shruti Amin 1E
When drawing the diagram with the two bumps (TS 1 and TS2), how do you know if the reaction is going to be endothermic or exothermic? The reactants will be higher on the diagram than the products if it is exothermic, but how do I know if it's exothermic?

Is it based on how many bonds break/form?

Re: Drawing/Labeling reaction profile

Posted: Mon Mar 06, 2017 1:23 pm
by Jenny_Luu_2A
You would be able to tell that the reaction is exothermic precisely because the reactants have a higher energy level than the products do. In an exothermic reaction, energy is released when you form bonds. And when bonds are formed to make products, they are going to be more stable than the reactants, and have a lower energy than the reactants.

Re: Drawing/Labeling reaction profile

Posted: Mon Mar 06, 2017 2:15 pm
by Chem_Mod
Be careful about which terms your are talking about here. Exothermic and endothermic refer to delta H. I assume because you're talking about reaction profiles, you want to be talking about delta G. If so, the terms are exergonic and endergonic.

Re: Drawing/Labeling reaction profile

Posted: Tue Mar 07, 2017 9:44 pm
by Patrick Ricaflanca 2H
My TA told me that the class would focus more on exergonic reactions. So when they tell us to draw the reaction profiles, they would also tell us if the reaction was exergonic or endergonic. If it's exergonic, the reactants start off higher than the products, and if endergonic vice versa.