Question

The terms order and molecularity are common in chemical kinetics.
(A) What do you mean by order and molecularity?
(B) (1) Write two factors influencing rate of reaction.
      (2) Write Arrhenius equation

Answer 1

Hint: Order of reaction is the sum of the concentration term on which the rate of reaction actually depends and while molecularity is the number of atoms, ions or molecules that must collide to result into a chemical reaction.

Complete step by step solution:
(A)

S.No.	ORDER OF A REACTION	MOLECULARITY OF A REACTION
	It is the sum of the exponents of the concentration in the rate law equation of any chemical reaction.	It is the necessary number of atoms, ions or molecules that need to collide with each other to make the reaction happen.
	It is given for the overall reaction.	For a complex reaction overall molecularity will not give any proper conclusion.
	There are no separate steps written to obtain it.	For the molecularity steps are important because the molecularity of the slowest step is significant here.
	It need not be a whole number that means it can be fractional.	It is always a whole number.
	It can’t be calculated. It is obtained experimentally.	It can be calculated by simply adding the molecules of the slowest step.
	The order of a simple reaction may not be equal to the number of molecules of the reactants as seen from the unbalanced equation of the chemical reaction.	Here for the simple reactions, the molecularity can be obtaining from the stoichiometry of the equation

(B)(1) Factors affecting the rate of reaction of a chemical reaction:
(i)Concentration of reactants, temperature,
(ii)The physical state of reactants and their dispersion, the solvent, and the presence of a catalyst.

(B)(2) Arrhenius equation:
\[K = {A^{\dfrac{{ - {E_a}}}{{RT}}}}\]
Where,
$K = $Rate constant
${E_{a = }}$Activation energy
$R = $ gas constant
$T = $temperature in kelvin.

Note: Here we see that the Arrhenius equation includes the rate constant, activation energy, gas constant and the temperature, so the question arises that what is the application of the Arrhenius equation. So the Arrhenius equation is used to determine the effect of the temperature on the rate constant and hence finally we are going to determine the effect of temperature on the rate of reaction because the rate of reaction and rate constant are in direct relation that means if the rate constant get doubled then the rate of reaction also become twice.