(Ea) The minimum energy required to convert reactants into products; the difference between the energies of the activated complex and the reactants.
In chemistry, activation energy is a term introduced in 1889 by the Swedish scientist Svante Arrhenius that means the minimum energy that must be input to a chemical system with potential reactants to cause a chemical reaction. Activation energy may also be defined as the minimum energy required to start a chemical reaction. The activation energy ...
in chemistry, the minimum amount of energy that is required to activate atoms or molecules to a condition in which they can undergo chemical ... [4 related articles]
See energy of activation.
is the minimum energy required to start a chemical reaction
Amount of energy that must be absorbed by reactants in their ground states to reach the transition state so that a reaction can occur.
The minimum energy needed for a specific chemical reaction to take place, even though the process may already be thermodynamically possible. In chemical kinetics, the activation energy is the height of the potential barrier separating the products and reactants. It determines the temperature depende...
Amount of energy that must be absorbed by reactants in their ground states to reach the transition state so that a reaction can occur. In other words, activation energy is the minimum energy required for a chemical reaction to occur.
<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) ... 
Energy needed to make substrate molecules more reactive eg. enzymes function by lowering activation energy.The energy required to bring a system from the ground state to the level at which a reaction will proceed.
The energy required to initiate a chemical reaction.
The energy required to initiate a chemical reaction.
[n] - the energy that an atomic system must acquire before a process (such as an emission or reaction) can occur
energy needed to form or break chemical bonds and convert a reactant or reactants to a product or products
For the forward reaction is the energy required to go from reactants to the transition state. The activation energy for the reverse reaction is the energy required to go from products to the transition state. 
energy of activation noun the energy that an atomic system must acquire before a process (such as an emission or reaction) can occur; `catalysts are said to reduce the energy of activation during the transition phase of a reaction`
In chemistry, the minimum energy required in order to start a chemical reaction. Some elements and compounds will react together merely by bringing them into contact (spontaneous reaction). For others it is necessary to supply energy (heat, radiation, or electrical charge) in order to start the reaction, even if there is ultimately a net output of ...