Arrhenius Collision Theory

IMPORTANT

Arrhenius Collision Theory: Overview

This Topic covers sub-topics such as Inhibitor, Arrhenius Equation, Intermediate Complex Theory, Graphical Representation of Rate Constant versus Temperature and, Effect of a Catalyst on Activation Energy of a Reaction

Important Questions on Arrhenius Collision Theory

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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)

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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
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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 )

MEDIUM
IMPORTANT

For the adsorption of hydrogen on platinum, the activation energy is 30 kJ mol1 and for the adsorption of hydrogen on nickel, the activation energy is 41.4 kJ mol1. The logarithm of the ratio of the rates of chemisorption on equal areas of the metals at 300 K is _______ (Nearest integer)

Given: In10=2.3

R=8.3 J K-1 mol-1

EASY
IMPORTANT

The correct reaction profile diagram for a positive catalyst reaction.

HARD
IMPORTANT

For the reaction CO(g)+Cl2gCOCl2g under the same concentration conditions of the reactants, the rate of reaction at 250oC IS 1500 times as fast as the same reaction at 150oC. Calculate the activation energy of the reaction.If the frequency factor is 2 × 10-10M-1sec-1 Calculate the rate constant of the reaction at 150oC.

MEDIUM
IMPORTANT

A bottle of milk stored at 300 K sours in 36 hours. When stored in a refrigerator at 275 K it sours in 360 hours. Calculate the energy of activation in kJ/mole of the reaction involved in the souring process. R=8.314 J K-1 mol-1.

Give the nearest integer as the answer.

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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

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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.

HARD
IMPORTANT

A certain physiologically important first-order reaction has activation energy equal to 45.0 kJ mol-1 at normal body temperature 37 °C.Without a catalyst, the rate constant for the reaction is 5.0×10-4s-1. To be effective in the human body, where the reaction is catalysed by an enzyme, the rate constant must be at least 2·0×10-2s-1. If the activation energy is the only factor affected by the presence of the enzyme, by how much must the enzyme lower the activation energy of the reaction to achieve the desired rate? (Report your answer by multiplying with 10 and rounding off to two significant figures)

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

A certain physiologically important first-order reaction has activation energy equal to 45.0 kJ mol-1at a normal body temperature 37 °C. Without a catalyst, the rate constant for the reaction is 5·0×10-4s-1. To be effective in the human body, where the reaction is catalysed by an enzyme, the rate constant must be at least 2·0×10-2s-1. If the activation energy is the only factor affected by the presence of the enzyme, by how much must the enzyme lower the activation energy of the reaction to achieve the desired rate? Give answer to the nearest integer  value after multiplying with 10.

HARD
IMPORTANT

A hydrogenation reaction is carried out at 500 K. If the same reaction is carried out in the presence of a catalyst at same rate, the temperature required is 400 K and if the catalyst lowers the activation energy by 20 kJ mol-1, the activation energy of uncatalyzed reaction at 500 K will be:

MEDIUM
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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:

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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
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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
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Which among the following equations represents Arrhenius equation ?

EASY
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The rate constant of a reaction is given by k=PZe-Ea/RT under standard notation In order to speed up the reaction, which of the following factors has to he decreased?

EASY
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The activation energy for the forward reaction, PQ is 20 kJ mol-1 and the enthalpy change, ΔH of the reaction is +10 kJ mol-1. The activation energy (in kJ mol-1) for the backward reaction will be

MEDIUM
IMPORTANT

Raw milk sours in 4 hours at 27°C, but in 40 hours in refrigerator at 7°C. What is activation energy (in KJ). for souring milk.

[Given R=8.3 J/mole-k, ln x=2.3 logx]

Round off your answer to the nearest integer.