[saly]

hi All,
I am struggling with this concept, I have the question and the answer but I just don't understant the concept, here is the question:

Increasing the temperature favors elimination reactions over substitutions. what reason can you give to account for this?

answer: Eliminations are favored at higher tempratures because eliminations have higher free energies of activation than substitution. the reasoning behind this is due to the fact that eliminations have a greater change in bonding ( more bonds are broken and formed). By giving more molecules enough energy to sumount energy barriers, increasing the temperature increase the rates of both substitutions and eliminations, however, because the energy barrier for eliminations are higher, the proportion of molecules able to cross them is significantly higher.

I specifically don't understand why is the activation energy higher for eliminations reactions....is it because more bonds are broken in eliminations rxns than in substitution rxns?? and secondly I don't understand the part I highlighted in green, this is how I understood this part: is it saying that at higher temp. more molecules can cross a higher activation barrier than a low activation barrier?? that doesn't make sence  

please explain in the simplest terms
thanks alot

[GCT]

how would raising the temperature affect the energy distribution of the molecules?

[saly]

I guess the moleculs will have more energy at higher temp. because there are more collisions

[GCT]

Do you think that those molecules with at the higher energy distribution will undergo a substitution or elimination reaction?  You'll need to consider the collision theory and think in terms of energy conservation.

[GCT]

Energy from collision is converted to energy to e.g. break the bonds, more energy will e.g. break more bonds...furnish the activation energy for the reaction.  It's simple as that