The energy that must be possessed by atoms or molecules in order to react.

The minimum energy required to convert reactants into products; the difference between the energies of the activated complex and the reactants.

In a chemical reaction, the energy that must be added to the reactants in order to allow a reaction to occur. See Arrhenius equation, preexponential factor.

The constant E in the exponential part of the Arrhenius equation, associated with the minimum energy difference between the reactants and an activated complex (transition state), which has a structure [..]

  The energy required to initiate a chemical reaction.

Microscopically, it is the energy Δε required to break the existing chemical bonds of colliding reactant molecules. Macroscopically, it can be thought of as the energy barrier ΔE that must be overcome for a chemical reaction to commence, or as the minimum energy required to start a chemical reaction. ΔE is often expressed in units of in kJ mol–1. Δ [..]

energy that is needed to get a reaction started

The energy necessary to start a chemical reaction; a measure of the minimum kinetic energy that colliding molecules must possess in order to react.

[noun] The energy required to initiate a chemical reaction or process, abbreviated Ea. For example, a cigarette lighter requires activation energy (provided in the form of a spark) to initiate the reaction of fuel with oxygen. Appears in modules:

Amount of energy needed to start a reaction (Lessons 12, 13)

The input of energy required to (overcome the barrier to) initiate a chemical reaction. By reducing the activation energy, an enzyme increases the rate of a reaction. (Figure 2-27)

See energy of activation

A physicochemical quantity that represents the barrier for a chemical reaction.

the minimum energy necessary to form an activated complex in a reaction.

Illustrated Glossary of Organic Chemistry Activation energy (energy of activation; Ea; Eact): The enthalpy difference (ΔH) between the reactants and transition state for any given reaction mechanism s [..]

When reactions proceed, a certain amount of energy is needed for the whole process to begin. The energy needed to get the reaction started (get it over the hump) is called the activation energy. The e [..]

The energy barrier that must be overcome during a collision of two potential reactants in order for a reaction to occur. [Dyes and Pigments; v74; 458-463; 2007.][Bioresource Technology; v100; 209; 948 [..]

<chemistry> The amount of energy (expressed in joules) that is needed to convert all the molecules in one mole of a reacting substance from a ground state to the transition state. (06 May 1997)

AKA: free energy of activation Energy needed to initiate a chemical reaction.

(chemistry,physics) The energy required to initiate a reaction. For example, the flame from the fuse of a firecracker provides a small initial amount of energy, after which the explosive reaction pr [..]