It has been suggested that theoretical yield be merged into this article or section. (Discuss)

Yield in chemistry, also known as chemical yield and reaction yield, is the amount of product obtained in a chemical reaction. The absolute yield can be given as the weight in gram or in mol (molar yield). The yield is usually also given as a relative yield, which is the actual yield divided by the theoretical yield (the ideal or mathematically calculated yield). The relative yield is usually given as a percentage value, the percent yield: Image File history File links Please see the file description page for further information. ... It has been suggested that this article or section be merged into Yield (chemistry). ... Chemistry (from Greek χημεία khemeia[1] meaning alchemy) is the science of matter at the atomic to molecular scale, dealing primarily with collections of atoms, such as molecules, crystals, and metals. ... A chemical reaction occurs when vapours of hydrogen chloride and ammonia meet to form a cloud of a new substance, ammonium chloride Chemical reaction is a process that results in the interconversion of chemical substances [1]. The substance or substances initially involved in a chemical reaction are called reactants. ... In the physical sciences, weight is a measurement of the gravitational force acting on an object. ... BIC pen cap, about 1 gram. ... The mole (symbol: mol) is the SI base unit that measures an amount of substance. ... A percentage is a way of expressing a proportion, a ratio or a fraction as a whole number, by using 100 as the denominator. ...

The theoretical yield value always relates to one of the reactants. This is usually the limiting one, taking into account the molar relation of the reactants and the stoichiometry of the reaction. A reactant or reagent is any substance initially present in a chemical reaction. ... [[Media:[[Media: == Stoichiometry (sometimes called reaction stoichiometry to distinguish it from composition stoichiometry) is the calculation of quantitative (measurable) relationships of the reactants and products in chemical reactions (chemical equations). ...

The ideal or theoretical yield of a chemical reaction would be 100%, a value that is rarely reached. Yields above about 90% are called very good, yields above about 75% are called good, yields below about 60% are called modest, yields below about 30% are called poor. Yields can also be above 100% when an extraneous chemical from outside of the reaction has found its way into the yield.

The theoretical yield for a specific reaction depends on the quantity of starting materials, particularly the limiting reagent. The theoretical yield is typically calculated assuming that there is only one reaction involved, that all of the reactant is converted into product, and that all the product is isolated in pure form. In chemistry, the limiting reagent is the chemical that determines how far the reaction will go before the chemical in question gets used up, causing the reaction to stop. ...

Example

This is an example of an esterification reaction where one molecule acetic acid reacts with one molecule ethanol, yielding one molecule ethyl acetate (a bimolecular second-order reaction of the type A + B → C): Esterification is the general name for a chemical reaction in which two chemicals (typically an alcohol and an acid) form an ester as the reaction product. ... Acetic acid, also known as ethanoic acid, is an organic chemical compound best recognized for giving vinegar its sour taste and pungent smell. ... Ethanol, also known as ethyl alcohol or grain alcohol, is a flammable, colorless, mildly toxic chemical compound with a distinctive perfume-like odor, and is the alcohol found in alcoholic beverages. ... Ethyl acetate is the organic compound with the formula CH3CH2OC(O)CH3. ... Order in the context of a chemical reaction is a concept of reaction kinetics, a subdiscipline of physical chemistry. ...

120 g acetic acid (60 g/mol, 2.0 mol) was reacted with 230 g ethanol (46 g/mol, 5.0 mol), yielding 132 g ethyl acetate (88 g/mol, 1.5 mol). The yield was 75%.

1. The molar amount of the reactants is calculated from their weight (acetic acid: 120 g ÷ 60 g/mol = 2.0 mol; ethanol: 230 g ÷ 46 g/mol = 5.0 mol).
2. Ethanol is used in a 2.5-fold excess (5.0 mol ÷ 2.0 mol).
3. The theoretical molar yield is 2.0 mol (the molar amount of the limiting compound, acetic acid).
4. The molar yield of the product is calculated from its weight (132 g ÷ 88 g/mol = 1.5 mol).
5. The % yield is calculated from the actual molar yield and the theoretical molar yield (1.5 mol ÷ 2.0 mol × 100% = 75%).