Why does a higher concentration increase the rate of reaction?

Question

a
It lowers the activation energy.
b
It increases the surface area of the particles
c
It decreases the amount of reactants.
d
It increases the frequency of collisions

Answer 1

The reason a higher concentration increases the rate of reaction is:

d It increases the frequency of collisions.

When the concentration of reactants is higher, there are more particles present in a given volume, which leads to an increased likelihood of particles colliding with each other. More collisions generally result in a higher rate of reaction, assuming the collisions have sufficient energy to overcome the activation energy barrier.