Primitive change

Possible processes are limited by the nature of system boundaries and by conditions in the surroundings. The kinds of processes allowed by particular boundaries are listed in Table 1.3. Often we cause a particular process to occur by bringing the system into contact with a reservoir that forces a particular system property to remain constant. Common reservoirs include the thermal (or heat) reservoir, which maintains the system at a constant temperature (an isothermal process), and the mechanical reservoir, which imposes its pressure on the system (isobaric process). 

We will find it useful to identify certain limiting cases of processes. To facilitate the discussion, we introduce the following notation. Let A represent the net total of aU 

Moreover, any driving force may be composed of both conservative and dissipative components we let jTrepresent all dissipative components of the driving forces. 

We first define the static limit of any process as that produced when all net driving 

This means that in the static limit, we expect any process to degenerate to an equilibrium state a physically realizable point on a state diagram. But note that to achieve equilibrium, all external and internal driving forces must be zero. In general, an equilibrium state is not obtained by taking only the external driving forces to zero for example, an isolated system need not be at equilibrium, nor need its state even be well-defined. 

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Step 1, Second Symbol. A bond is being broken between C and H. The symbol is D. In any process, the subscript is E if a core atom is forming a bond to an electrophile (Ag) or breaking a bond to an electrofuge (De). Since C is a core atom, the symbol here is De- Alternatively, the symbol could be Dh- The rules allow Ah or Dh to replace Ae or De if the electrophile or electrofuge is H. Because a core atom is involved in this primitive change the H in the subscript is capitalized. 

A reaction or set of reactions that consists of several elementary reactions. See also Elementary Reaction Primitive Change Parallel Reactions Series Reactions... 

Two or more primitive chemical/physical changes occurring within the same elementary reaction step. Typically, the simultaneous progress of these changes is thermodynamically more favorable than a set of successive changes. See Primitive Changes Elementary Reactions Synchronous lUPAC (1979) Pure and Appl. Chem. 51, 1725. 

F,F ATPase COMPLEX REACTION ELEMENTARY REACTION PRIMITIVE CHANGE PARALLEL REACTIONS SERIES REACTIONS OOMPONENT... 

COOPERATIVITY CONCERTED PROCESS PRIMITIVE CHANGES ELEMENTARY REACTIONS SYNCHRONOUS Condensation equilibrium,... 

PRIMARY PHOTOCHEMICAL PROCESS PRIMARY PHOTOPRODUCT PRIMARY PHOTOPRODUCT PRIMITIVE CHANGE... 

All oxidations meet criteria (1) and (2), and many meet criterion (3), but this is not always easy to demonstrate. Alternatively, an oxidation can be described as a transformation of an organic substrate that can be rationally dissected into steps or primitive changes. The latter consist in removal of one or several electrons from the substrate followed or preceded by gain or loss of water and/or hydrons or hydroxide ions, or by NUCLEOPHILIC substitution by water or its reverse and/or by an intramolecular molecular rearrangement. 

The concept of primitive changes is helpful in the detailed verbal description of elementary reactions, but a primitive change does not represent a process that is by itself necessarily observable as a component of an elementary reaction. 

These concepts are so basic that we call them primitives, for everything in later chapters builds on these ideas. You have probably encountered this material before, but our presentation may be new to you. The chapter is divided into primitive things ( 1.1), primitive quantities ( 1.2), primitive changes ( 1.3), and primitive analyses ( 1.4). 

Concerted Two or more primitive changes are said to be concerted (or to constitute a concerted process) if they occur within the same elementary reaction. Such changes will normally (though perhaps not inevitably) be energetically coupled . 

Synchronous A concerted process in which the primitive changes concerned (generally bond rupture and bond formation) have progressed to the same (or comparable) extent at the transition state is said to be synchronous [29]... 

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