Factors affecting reaction rate.

Question

Use collision theory to explain.

Factor: nature of the reactant
Affect on rate: more or less reactive based on its chemical identity.
reactivity:
aq>g>l>s

Explanation:

For the other factors, we had to explain it based on whether the factor helped the collisions have sufficient energy or have correct orientation.

For "nature of the reactant", I'm not too sure how to explain. For example, I could say if a chemical is aqueous, then it's just free-floating ions in solution so the bonds are already broken. This could increase the reaction rate because it has lots of energy but I also think it could be because since they're free-floating ions, there's more chance of colliding with correct orientation??
Same with gases; lots of energy, and they're floating around...
Solids have low energy and they don't move that much...?

I don't know.

Also, for catalysts, what would the explanation be based on collision theory?
I know catalysts "increase the rate of the reaction by providing an alternate reaction pathway, increasing the number of successful collisions"
but does it increase the number of successful collisions by providing sufficient energy to the particles or by increasing the chance of collisions with correct orientation (like for surface area, smaller particles result in more collisions with correct orientation)...?

Answer 1

For the catalyst, the rate is increased because the activation energy barrier is lowered (that's the alternate path) so more particles with the right energy can meet(collide) and react.