Arrhenius Collision Theory

IMPORTANT

Arrhenius Collision Theory: Overview

This Topic covers sub-topics such as Arrhenius Equation, Temperature Coefficient, Collision Frequency, Frequency Factor, Collision Theory of Chemical Reactions, Effective Collisions and, Effect of Temperature on Rate of a Reaction

Important Questions on Arrhenius Collision Theory

HARD
IMPORTANT

The rate of a reaction escalates four times when the temperature changes from 300 K to 320 K. Determine the energy of activation of the reaction, assuming that it does not change with temperature? (R=8.314JK1mol1)

MEDIUM
IMPORTANT

The minimum energy required to start a chemical reaction is known as:

HARD
IMPORTANT

The activation energy for the reaction 2HI(g)H2(g)+I2(g)  is 209.5kJmol1 at 581K. The fraction of molecules having energy equal to or greater than activation energy is: [R=8.31JK1mol1]

HARD
IMPORTANT

For a decomposition reaction the values of rate constant k at two different temperatures are given below :

  k 1 =2.15× 10 8 Lmo l 1 s 1 at650K k 2 =2.39× 10 7 Lmo l 1 s 1 at700K

The value of activation energy for this reaction is:

  (R=8.314J K 1 mo l 1 )

EASY
IMPORTANT

The factors which influence the rate of reaction are :

Concentration: Greater the concentrations of the reactants, faster is the rate of reaction.

Temperature: The rate of reaction increases with increase in temperature. For most of the reactions, the rate of reaction becomes almost double with 10o rise in temperature.

Presence of catalyst: A catalyst generally increases the speed of a reaction.

Answer the following question :

A small increase in temperature of the reacting system, the rate of reaction exceed to large extend. The most appropriate reason for this is-

HARD
IMPORTANT

In a reversible reaction, the enthalpy change and the activation energy in the forward direction are respectively x kJ mol-1 and y kJ mol-1. Therefore, the energy of activation in the backward direction is

HARD
IMPORTANT

Among the following graphs showing variation of rate constant with temperature (T) for a reaction, the one that exhibits Arrhenius behaviour over the entire temperature range is

HARD
IMPORTANT

Addition of a catalyst at 300 K increases the rate of a chemical reaction by a factor of 36. By how many kJ, the activation energy of the catalysed pathway is less than the activation energy of the original pathway approximately log6=0.78 and R=8.3 J k-1mol-1.

MEDIUM
IMPORTANT

Two reactions A1 and A2 have identical pre-exponential factors. The activation energy of A1 is more than A2 by 10 kJ mol-1 . If k1 and k2 are the rate constants for reactions A1 and A2, respectively at 300 K, then lnk2k1 is equal to

R=8.314 J mol-1K-1

HARD
IMPORTANT

For the given chemical reactions,

AB; k1=1010e-20,000/T

CD; k2=1012e-24,606/T

Calculate the temperature T at which k1 becomes equal to k2.

MEDIUM
IMPORTANT

In Arrhenius equation, k=Ae-Ea/RT;A  may be called the rate constant at:

HARD
IMPORTANT

Activation energy of a chemical reaction can be determined by:

HARD
IMPORTANT

The rate constant of the first-order reaction, i.e., decomposition of ethylene oxide into CH4 and CO may be described by the following equation: log k s-1=14.34-1.25×104TK.

Find the energy of activation (in kJ/mole). Report answer till the nearest integer.

MEDIUM
IMPORTANT

A certain physiologically important first-order reaction has an activation energy equal to 45.0 kJ/mol at normal body temperature 37°C. Without a catalyst, the rate constant for the reaction is 5.0×10-4 s-1. To be effective in the human body, where the reaction is catalysed by an enzyme, the rate constant must be at least  2.0×10-2 s-1. If the activation energy is the only factor affected by the presence of the enzyme, by how much kJ must the enzyme lower the activation energy of the reaction to achieve the desired rate?

Report the answer by multiplying the value with 10 and rounding off to two significant figures.

HARD
IMPORTANT

The temperature coefficient of the rate of a reaction is 2.3. How many times will the rate of the reaction increase if the temperature is raised by 25K? Give answer to the nearest integer.

MEDIUM
IMPORTANT

The rate of a reaction decreased by 3.555 times when the temperature was changed from 40°C to 30°C. The activation energy (in KJmol-1) of the reaction is.........(Report the answer in the nearest integer value)

[Take; R=8.314 J mol-1 K-1 and  ln 3.555=1.268]

MEDIUM
IMPORTANT

For the reaction, aA+bBcC+dD, the plot of log k vs 1 T is given below:

Question Image

The temperature at which the rate constant of the reaction is 10-4 s-1 is [Rounded off to the nearest integer) [Given: The rate constant of the reaction is 10-5 s-1 at 500 K]

MEDIUM
IMPORTANT

In the lnv1T plot of a chemical process having S0>0 and Ho<0 the slope is proportional to (where K is equilibrium constant)

MEDIUM
IMPORTANT

Collision theory is applicable to 

EASY
IMPORTANT

For a first order chemical reaction,