What is the difference between activation energy and activated complex?

Asked By: Danny Pinkernelle | Last Updated: 4th March, 2020
Category: science chemistry
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Activated complex is an intermediate structure formed in the conversion of reactants to products. The activated complex is the structure at the maximum energy point along the reaction path; the activation energy is the difference between the energies of the activated complex and the reactants.

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Thereof, how is activation energy related to activated complex?

An activated complex is an intermediate state that is formed during the conversion of reactants into products. The activation energy of a chemical reaction is the difference between the energy of the activated complex and the energy of the reactants.

Furthermore, what is the activated complex on a graph? The activated complex is the complex that exists as the bonds in the products are forming and the bonds in the reactants are breaking. We show this on the energy graphs by drawing a curve from the energy of the reactants to the energy of the products.

Thereof, what is another name for activated complex?

Transition state. (sometimes) another name for the activated complex, because the very unstable activated complex is as likely to re-form reactants as it is to form products.

What is the best definition of activation energy?

the energy required to end a chemical reaction. the energy required to bind a substrate to an active site. the energy required to break the bonds of reactant molecules. the energy required to re-form bonds in product molecules.

30 Related Question Answers Found

Is activation energy always positive?

The rate of a reaction always increases with increasing temperature (higher rate of collisions), so the activation energy is always positive. For some reactions, the activation energy is very low, so even at lower temperatures, the rate constant approaches the pre-exponential factor.

What is the potential energy of the activated complex?

For a chemical reaction to occur, there must be a contact (collision) between the reactants. For further details about the reaction rate, see the Definition of A Reaction Rate. As the reaction proceeds, the potential energy rises to a maximum and the reactants form a cluster of atoms, called the activated complex.

What are some examples of activation energy?

This energy is called activation energy. For example, activation energy is needed to start a car engine. Turning the key causes a spark that activates the burning of gasoline in the engine. The combustion of gas won't occur without the spark of energy to begin the reaction.

What is meant catalyst?

A catalyst is a substance that speeds up a chemical reaction, but is not consumed by the reaction; hence a catalyst can be recovered chemically unchanged at the end of the reaction it has been used to speed up, or catalyze.

What is the lifetime of an activated complex?


The lifetime of an activated complex is typically about 10-13 seconds. Its brief existence ends with the reformation of the reactants or with the formation of products. Thus, the activated complex is sometimes called the transition state.

How do you draw an activation energy diagram?

1 Answer
  1. Draw and label a pair of axes. Label the vertical axis "Potential Energy" and the horizontal axis "Reaction Coordinate".
  2. Draw and label two short horizontal lines to mark the energies of the reactants and products.
  3. Draw the energy level diagram.
  4. Draw and label the activation energy.

How is activation energy related to the energy of reaction?

The activation energy of a chemical reaction is closely related to its rate. Specifically, the higher the activation energy, the slower the chemical reaction will be. This is because molecules can only complete the reaction once they have reached the top of the activation energy barrier.

Is activated complex the transition state?

On the reaction path between the initial and final arrangements of atoms or molecules, there exists an intermediate configuration at which the potential energy has a maximum value. The configuration corresponding to this maximum is known as the activated complex, and its state is referred to as the transition state.

How do Catalysts speed up reactions?

A catalyst is a substance that can be added to a reaction to increase the reaction rate without getting consumed in the process. Catalysts typically speed up a reaction by reducing the activation energy or changing the reaction mechanism. Enzymes are proteins that act as catalysts in biochemical reactions.

What is Delta H?


In chemistry, the letter "H" represents the enthalpy of a system. Enthalpy refers to the sum of the internal energy of a system plus the product of the system's pressure and volume. The delta symbol is used to represent change. Therefore, delta H represents the change in enthalpy of a system in a reaction.

What species is the activated complex?

Postulates of Transition State Theory
The species that forms during the transition state is a higher-energy species known as the activated complex. TST postulates three major factors that determine whether or not a reaction will occur.

How do you calculate activation energy?

Activation Energy Problem
  1. Step 1: Convert temperatures from degrees Celsius to Kelvin. T = degrees Celsius + 273.15. T1 = 3 + 273.15.
  2. Step 2 - Find Ea ln(k2/k1) = Ea/R x (1/T1 - 1/T2)
  3. Answer: The activation energy for this reaction is 4.59 x 104 J/mol or 45.9 kJ/mol.

Can activated complex be isolated?

The activated complex is an unstable (unobserved) structure corresponding to an energy maximum in the reaction profile. An intermediate is the chemical structure present at the transition state. An activated complex can not be isolated or observed in a chemical reaction.

What is the rate law for the overall reaction?

Solution: The rate is directly proportional to the concentration of the first reactant. When the concentration of the reactant doubles, the rate also doubles. Because the reaction is third-order, the sum of the exponents in the rate law must be equal to 3.

What does an energy diagram show?


The energy changes that occur during a chemical reaction can be shown in a diagram called a potential energy diagram, or sometimes called a reaction progress curve. A potential energy diagram shows the change in potential energy of a system as reactants are converted into products.

What condition must be met for an activated complex?

According to the collision theory, the following criteria must be met in order for a chemical reaction to occur: Molecules must collide with sufficient energy, known as the activation energy, so that chemical bonds can break. Molecules must collide with the proper orientation.

How do you determine the rate determining step in an energy diagram?

3 Answers. Yes, the rate determining step is the largest energy difference between any starting material or intermediate on a potential energy diagram and any transition state that comes after it. That transition state will then be the rate-determining step of a given reaction.