Rate of formationIUPAC Term

for kinetics in closed systems it is more usual to define a rate of formation per unit volume, denoted vcy: vcy 1v ny t when the volume is constant this reduces to: vcy 1v ny t y t when the volume is not constant the relationship ny y v may be differentiated to give: ny v y y v and the rate of formation becomes: vcy y t yv v t a rate of formation may be specified even for a reaction of time dependent stoichiometry or of unknown stoichiometry.
as the time derivative of the amount of a product. thus for a product y, present at any time in amountny. the rate of its formation may be given by: vny ny t this definition is particularly appropriate for open systems.