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One reactant (A) is chosen, and the balanced chemical equation is used to determine the amount of the other reactant (B) necessary to react with A. If the amount of B actually present exceeds the amount required, then B is in excess and A is the limiting reagent. If the amount of B present is less than required, then B is the limiting reagent.
Conversion and its related terms yield and selectivity are important terms in chemical reaction engineering.They are described as ratios of how much of a reactant has reacted (X — conversion, normally between zero and one), how much of a desired product was formed (Y — yield, normally also between zero and one) and how much desired product was formed in ratio to the undesired product(s) (S ...
To find the limiting reagent and the mass of HCl produced by the reaction, we change the above amounts by a factor of 90/324.41 and obtain the following amounts: 90.00 g FeCl 3, 28.37 g H 2 S, 57.67 g Fe 2 S 3, 60.69 g HCl. The limiting reactant (or reagent) is FeCl 3, since all 90.00 g of it is used up while only 28.37 g H 2 S are consumed.
In addition, for a single reaction a conversion may be defined in terms of the limiting reactant, for the simple decomposition that is species ...
Stoichiometric equations are used to determine the limiting reagent or reactant—the reactant that is completely consumed in a reaction. The limiting reagent determines the theoretical yield—the relative quantity of moles of reactants and the product formed in a chemical reaction. Other reactants are said to be present in excess.
An element–reaction–product table is used to find coefficients while balancing an equation representing a chemical reaction. Coefficients represent moles of a substance so that the number of atoms produced is equal to the number of atoms being reacted with. [1] This is the common setup: Element: all the elements that are in the reaction ...
where denotes the number of moles of the reactant or product and is the stoichiometric number [4] of the reactant or product. Although less common, we see from this expression that since the stoichiometric number can either be considered to be dimensionless or to have units of moles, conversely the extent of reaction can either be considered to ...
In principle, the time evolution of the reactant and product concentrations can be determined from the set of simultaneous rate equations for the individual steps of the mechanism, one for each step. However, the analytical solution of these differential equations is not always easy, and in some cases numerical integration may even be required. [4]