English

Define activation energy.

Advertisements
Advertisements

Questions

Define activation energy.

Define the following term:

Activation energy

Define energy of activation of a reaction.

Definition
Advertisements

Solution 1

Activation energy is the lowest energy necessary to commence a chemical reaction by disrupting the bonds of reactant molecules and creating the activated complex or transition state. It signifies the energy threshold that must be surmounted for a reaction to transpire. Activation energy is typically represented as Ea.

shaalaa.com

Solution 2

Activation energy may be defined as the excess energy that the reactant molecules (having energy less than the threshold energy) must acquire in order to cross the energy barrier and to change into the products.

shaalaa.com
  Is there an error in this question or solution?
Chapter 3: Chemical Kinetics - REVIEW EXERCISES [Page 250]

APPEARS IN

Nootan Chemistry [English] Class 12 ISC
Chapter 3 Chemical Kinetics
REVIEW EXERCISES | Q 4.70 i. | Page 250
Nootan Chemistry [English] Class 12 ISC
Chapter 3 Chemical Kinetics
REVIEW EXERCISES | Q 4.82 | Page 250
Nootan Chemistry [English] Class 12 ISC
Chapter 3 Chemical Kinetics
REVIEW EXERCISES | Q 4.69 i. | Page 250
Nootan Chemistry [English] Class 12 ISC
Chapter 3 Chemical Kinetics
VERY SHORT ANSWER TYPE QUESTIONS | Q 42. | Page 263

Video TutorialsVIEW ALL [1]

RELATED QUESTIONS

The rate constant of a first order reaction increases from 4 × 10−2 to 8 × 10−2 when the temperature changes from 27°C to 37°C. Calculate the energy of activation (Ea). (log 2 = 0.301, log 3 = 0.4771, log 4 = 0.6021)


What will be the effect of temperature on rate constant?


The rate of the chemical reaction doubles for an increase of 10 K in absolute temperature from 298 K. Calculate Ea.


The rate constant for the decomposition of hydrocarbons is 2.418 × 10−5 s−1 at 546 K. If the energy of activation is 179.9 kJ/mol, what will be the value of pre-exponential factor?


Consider a certain reaction \[\ce{A -> Products}\] with k = 2.0 × 10−2 s−1. Calculate the concentration of A remaining after 100 s if the initial concentration of A is 1.0 mol L−1.


The decomposition of hydrocarbon follows the equation k = `(4.5 xx 10^11 s^-1) e^(-28000 K//T)`

Calculate Ea.


The rate constant of a first order reaction are 0.58 S-1 at 313 K and 0.045 S-1 at 293 K. What is the energy of activation for the reaction?


Calculate activation energy for a reaction of which rate constant becomes four times when temperature changes from 30 °C to 50 °C. (Given R = 8.314 JK−1 mol−1). 


What is the effect of adding a catalyst on Activation energy (Ea)


A first-order reaction is 50% completed in 40 minutes at 300 K and in 20 minutes at 320 K. Calculate the activation energy of the reaction. (Given : log 2 = 0·3010, log 4 = 0·6021, R = 8·314 JK–1 mol–1)


The decomposition of a hydrocarbon has value of rate constant as 2.5×104s-1 At 27° what temperature would rate constant be 7.5×104 × 3 s-1if energy of activation is  19.147 × 103 J mol-1 ?


 Write a condition under which a bimolecular reaction is kinetically first order. Give an example of  such a reaction. (Given : log2 = 0.3010,log 3 = 0.4771, log5 = 0.6990).


 Predict the main product of the following reactions:


The chemical reaction in which reactants require high amount of activation energy are generally ____________.


The rate of chemical reaction becomes double for every 10° rise in temperature because of ____________.


Activation energy of a chemical reaction can be determined by ______.


Which of the following graphs represents exothermic reaction?

(a)  

(b)  

(c)  


Why does the rate of a reaction increase with rise in temperature?


Match the statements given in Column I and Column II

  Column I Column I
(i) Catalyst alters the rate of reaction (a) cannot be fraction or zero
(ii) Molecularity (b) proper orientation is not there always
(iii) Second half life of first order reaction (c) by lowering the activation energy
(iv) `e^((-E_a)/(RT)` (d) is same as the first
(v) Energetically favourable reactions (e) total probability is one are sometimes slow (e) total probability is one
(vi) Area under the Maxwell Boltzman curve is constant (f) refers to the fraction of molecules with energy equal to or greater than activation energy

What happens to most probable kinetic energy and the energy of activation with increase in temperature?


For an endothermic reaction energy of activation is Ea and enthalpy of reaction ΔH (both of there in KJ moI–1) minimum value of Ea will be ______.


In respect of the eqn k = \[\ce{Ae^{{-E_a}/{RT}}}\] in chemical kinetics, which one of the following statement is correct?


The activation energy in a chemical reaction is defined as ______.


Explain how and why will the rate of reaction for a given reaction be affected when the temperature at which the reaction was taking place is decreased.


The activation energy of one of the reactions in a biochemical process is 532611 J mol–1. When the temperature falls from 310 K to 300 K, the change in rate constant observed is k300 = x × 10–3 k310. The value of x is ______.

[Given: ln 10 = 2.3, R = 8.3 J K–1 mol–1]


The equation k = `(6.5 xx 10^12 "s"^(-1))"e"^(- 26000 " K"//"T")` is followed for the decomposition of compound A. The activation energy for the reaction is ______ kJ mol-1. (Nearest integer) (Given: R = 8.314 JK-1 mol-1)


The decomposition of N2O into N2 and O2 in the presence of gaseous argon follows second-order kinetics, with k = (5.0 × 1011 L mol−1 s−1) `"e"^(-(29000  "K")/"T")`. Arrhenius parameters are ______ kJ mol−1.


An exothermic reaction X → Y has an activation energy 30 kJ mol-1. If energy change ΔE during the reaction is - 20 kJ, then the activation energy for the reverse reaction in kJ is ______.


A schematic plot of ln Keq versus inverse of temperature for a reaction is shown below

The reaction must be:


What happens to the rate constant k and activation energy Ea as the temperature of a chemical reaction is increased? Justify.


Which plot of ln k vs `1/T` is consistent with the Arrhenius equation?


Activation energy of any chemical reactions can be calculated if one knows the value of:


The rate of a reaction quadruples when temperature changes from 27°C to 57°C calculate the energy of activation. 

(Given: R = 8. 314 J K−1 mol−1, log 4 = 0.6021)


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×