Rate of Reaction vs. Rate Constant

Main Difference

The main difference between the rate of reaction and rate constant is that the rate of reaction refers to the mole per sec as the change in molar concentration of reactants and products with time, whereas the rate constant refers to the constant of proportionality of a particular chemical reaction.

Difference Between Rate of Reaction and Rate Constant

Comparison Chart

Rate of Reaction vs. Rate Constant

Reaction rate defined as the change in the number of reactants and products with time, whereas the rate constant defined as the specific constant of proportionality of a particular chemical reaction. The rate of reaction directly rests on reactants and products’ molar concentrations, while the rate constant does not rest on reactants and products’ molar concentrations. The rate of a reaction indirectly rests on the physical properties like temperature; on the other hand, the rate constant directly rests on the physical properties like temperature.

The rate of reaction mainly needs the time of the completion of a reaction on the flip side; the rate constant does not need the time of the completion of a reaction. The rate of a reaction depends upon pressure, while the rate constant does not depend upon pressure. The rate of reaction can change with the help of catalysts, whereas the rate constant does not show any change in the presence of catalysts.

The rate of reaction always expressed in mole per sec, while the rate constant is taken from the reaction directly. The unit of rate of reaction does not subject to an order of reaction, whereas the unit of a constant rate subject to the order of the reaction or can find out with the help of an order of a reaction. The rate of reaction directly or indirectly depends on the frequency of collisions, whereas the rate constant does not mainly depend on the frequency of collision.

What is the Rate of Reaction?

The rate of reaction refers to the mole per sec change in the concentration of reactants and products with time. It also depends on the physical properties like temperature. It fluctuates with the deviation of temperature. It also depends on the time of completion of the reaction. Longer the time, larger will be the value of the rate of reaction.

It depends on temperature indirectly. It can be changed with the change in pressure and catalysts. The main factor that is involved in increasing the value of the rate of reaction is the increase in the frequency of collision of reacting molecules. The units of the rate of reaction can be found with the help of the order of the reaction.

The rate of the reaction always said to increase if the molar concentration of the reactants is decreasing, and the molar concentration of the products is increasing. In the same way, the rate of reaction always said to decrease if the molar concentration of reactants is increasing, and the molar concentration of products is decreasing.

What is Rate Constant?

Rate constant defined as the specific constant of proportionality. It does not rest on the concentration of moles. It is importantly rested on the physical properties like temperature. It can only change with the change in temperature. Other quantities do not affect the rate constant such as pressure and catalysts.

It also does not depend on the time for completion of a reaction. It does not change whether a reaction occurs in no time or occurs abruptly. The frequency of collision of reacting molecules does not affect changing the rate constant. K can denote it.

This constant is helpful and determining the rate of reaction at any time during the reaction. The increase or decrease in a rate constant can only be determined by the physical properties such as temperature.

Conclusion

The above discussion concludes that the rate of reaction is the molar change in the reactant and product concentration per unit time, whereas the rate constant is proportionality constant of a specific reaction.