Factors that Influence Reaction Rate

Basically, reaction rate is influenced by several factors:

1. Surface are

2. Concentration

3. Temperature

4. Pressure

5. Catalyst

a. Surface Area

The reaction rate is influenced by the surface area between reactants. A solid will react more quickly if its surface is widened by changing its form bar to powder or making the size smaller. The reaction rate increase happens because smaller pieces of the same mass of solid have a greater surface area compared to larger pieces of the solid. So the collision of the solid which have the small pieces is more than large pieces.

b. Temperature

The change in temperature will affect the reaction rate. Generally, the increase of temperature will increase the reaction rate. The increasing of temperature causes kinetic energy of reactant molecules increase, so its kinetic energy has higher point than its activation energy (Ea) or kinetic energy can reach activation energy (Ea). Generally, for each 10º C increasing of temperature, the reaction rate of the second reaction will be twice as fast as the initial reaction.

c. Concentration

The concentration of solution affect the reaction rate. Increasing the concentration of reactants will increase the frequency of collision among the reactants particles. This is because in a concentrated solution, the distance among particles is relatively close, so they are easy to collide.

d. Pressure

More reaction in daily life using reactants on gas state. The reaction rate of this reaction is influence by pressure. The increasing pressure will be decrease volume and increase concentration. So, the reaction rate of this reaction will be increase.

e. Catalyst

Catalyst is a substance that increase the rate of chemical reaction without its self undergoing any change.

Example: using MnO2 on the dissociation of H2O2

2 H2O2(aq) → 2H2O(l) + O2(g)

At room temperature, reaction is happened very slowly. However, reaction will be happened very strong after adding FeCl3