Why do chemical reactions tend to speed up when the concentration of the reactants is increased?

Question

Quizplus · Accepted Answer

When the concentration of reactants is increased, there are more molecules present in a given volume which leads to an increased likelihood of collisions between reactant molecules, thus increasing the rate of reaction. Factors A and B (greater energy and faster movement) may also be present, but the primary reason for the increased rate of reaction is the higher collision frequency.

Why Do Chemical Reactions Tend to Speed Up When the Concentration