Please forward this error screen to 216. In chemistry, yield, also referred to as reaction yield, is the amount of product obtained in a chemical reaction. Calculation in chemistry textbook pdf theoretical yield is the amount predicted by a stoichiometric calculation based on the number of moles of all reactants present.
This calculation assumes that only one reaction occurs and that the limiting reactant reacts completely. Many reactions are incomplete and the reactants are not completely converted to products.
If a reverse reaction occurs, the final state contains both reactants and products in a state of chemical equilibrium. Two or more reactions may occur simultaneously, so that some reactant is converted to undesired by-products. Losses occur in the separation and purification of the desired product from the reaction mixture. These names are arbitrary and not universally accepted, and depending on the nature of the reaction in question, these expectations may be unrealistically high.
Purification steps always lower the yield, through losses incurred during the transfer of material between reaction vessels and purification apparatus or imperfect separation of the product from impurities, which may necessitate the discarding of fractions deemed insufficiently pure. A yield determined using this approach is known as an internal standard yield.