Question

all of the following factors help to speed up chemical reactions except ____________. increased particle size increased temperature catalysts high concentrations of reactants

Explanation:

Increased particle size reduces the surface - area to volume ratio, decreasing the contact between reactants and thus slowing down chemical reactions. Increased temperature provides more kinetic energy to reactant molecules, catalysts lower the activation energy, and high concentrations of reactants increase the frequency of collisions, all of which speed up reactions.

Answer:

increased particle size