What is one method to decrease the rate of a chemical reaction?

Using a larger particle size is effective in decreasing the rate of a chemical reaction primarily because it reduces the surface area of the reactants that are available for reaction. In chemical reactions, reactants must collide with each other to react. A larger particle size means there are fewer particles exposed to each other which leads to fewer collisions occurring over a given period.

In contrast, increasing temperature typically speeds up reactions as it increases the kinetic energy of the particles, causing them to move faster and collide more frequently. Decreasing particle size or increasing concentration enhances the rate of reactions by increasing the surface area or the number of particles available for collisions, respectively. Therefore, a larger particle size effectively slows the reaction down due to the limited opportunities for collisions.