Question

Give a brief definition of the following terms (a

Answer 1

a) 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

b)

the protein component of an enzyme separable from the prosthetic group (coenzyme) butrequiring the presence of the prosthetic group to form the functioning compound (holoenzyme).

c) Heterogeneous reaction, any of a class of chemical reactions in which the reactants are components of two or more phases (solid and gas, solid and liquid, two immiscible liquids) or in which one or more reactants undergo chemical change at an interface, e.g., on the surface of a solid catalyst. The reaction of metals with acids, the electrochemical changes that occur in batteries and electrolytic cells, and the phenomena of corrosion are part of the subject of heterogeneous reactions. By far the majority of the researches on heterogeneous reactions are devoted to heterogeneous catalysis

d) Diffusion-controlled (or diffusion-limited) reactions are reactions that occur so quickly that the reaction rate is the rate of transport of the reactants through the reaction medium (usually a solution). As quickly as the reactants encounter each other, they react. The process of chemical reaction can be considered as involving the diffusion of reactants until they encounter each other in the right stoichiometry and form an activated complex which can form the product species. The observed rate of chemical reactions is, generally speaking, the rate of the slowest or "rate determining" step. In diffusion controlled reactions the formation of products from the activated complex is much faster than the diffusion of reactants and thus the rate is governed by collision frequency.

e) In chemistry, a reaction mechanism is the step by step sequence of elementaryreactions by which overall chemical change occurs