Stoichiometry average atomic mass

Stoichiometry is defined as the mass balance of chemical reactions as they relate to the law of definite proportions and conservation of mass. The Redfield ratio provides the most well-known example of stoichiometric distinction where the average atomic ratios of C, N, and P in phytoplankton are relatively consistent (106 16 1) in most marine species. 

Table 2.1 contains averaged data for 28 different chemistries commonly used in industry. The stoichiometry, yield, atom economy, reaction mass efficiency, mass intensity, and mass productivity are shown for each type of chemistry. 

The general equations of partition function and canonical distribution have been applied to a reaction of stoichiometry 1—1, which is the case encountered in transactinide chemistry. Guillaumont et al. demonstrated that only in this case, the law of mass action holds, regardless of the number of present species, if the mean concentrations are used. However, when less than hundred atoms are involved in a reaction with a stoichiometry different from 1—1, deviations from the law of mass action can occur. For instance, in highly diluted solution, disproportionation of Pu(IV) and oxidation of U(TV) with Fe(lll) have been proved to display an erratic behavior with respect to the law of mass action. Thus, there is no general solution to describe the average populations when few atoms participate in a chemical reaction with a stoichiometry different from 1—1 [4, 5]. 

The sum of the atomic weights of all the atoms present in a molecule. The term molecular weight is commonly used although actually masses are involved. The average molecular weight is calculated taking the natural isotopic distribution of the elements into account (stoichiometry). 

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