Calculation, percent limiting reagent

Chemical stoichiometry is the area of study that considers the quantities of materials in chemical formulas and equations. Quite simply, it is chemical arithmetic. The word itself is derived from stoicheion, the Greek word for element and metron, the Greek word for measure. When based on chemical formulas, stoichiometry is used to convert between mass and moles, to calculate the number of atoms, to calculate percent composition, and to interpret the mole ratios expressed in a chemical formula. Most topics in chemical arithmetic depend on the interpretation of balanced chemical equations. Mass/mole conversions, calculation of limiting reagent and percent yield, and various relationships among reactants and products are commonly included in this topic area. 

Calculate the moles of each reactant from the masses and molar masses. Then calculate the yield based on the limiting reagent. The mass of the product, determined at the end of the synthesis, divided by the mass calculated from the limiting reagent times 100%, gives the percent yield. There are numerous possible analysis calculations. 

When the mass of the product (actual yield) is measured, normally a percent yield is required. The mass of the limiting reagent is converted, through moles, to the theoretical yield of product. The percent yield is calculated by dividing the actual yield by the theoretical yield, then multiplying the resulting value by 100%. 

A. 81.37% is the percent yield. The question clearly notes that sodium hydroxide is the excess reagent. (Tip You always can ignore a reactant if the problem says it s in excess. That s like a big this-one-isn t-important sign in the problem.) So sulfuric acid is the limiting reagent and is the reagent you should use to calculate the theoretical yield ... 

The yield of a reaction is the amount of product obtained. This value is nearly always less than what would be predicted from a stoichiometric calculation because side-reactions may produce different products, the reverse reaction may occur, and some material may be lost during the procedure. The yield from a stoichiometric calculation on the limiting reagent is called the theoretical yield. Percent yield is the actual yield divided by the theoretical yield times 100% ... 

Stoichiometry is the quantitative study of products and reactants in chemical reactions. Stoichiometric calculations are best done by expressing both the known and unknown quantities in terms of moles and then converting to other units if necessary. A limiting reagent is the reactant that is present in the smallest stoichiometric amount. It limits the amount of product that can be formed. The amount of product obtained in a reaction (the actual yield) may be less than the maximum possible amount (the theoretical yield). The ratio of the two is expressed as the percent yield. 

Skill 2.1b-Calculate the masses of reactants and products, and percent yield using balanced chemical equations, including problems with a limiting reagent... 

A limiting reactant is completely consumed in a reaction. When it is used up, the reaction stops, thus limiting the quantities of products formed. The theoretical yield of a reaction is the quantity of product calculated to form when all of the limiting reagent reacts. The actual yield of a reaction is always less titan the theoretical yield. The percent )deld compares the actual and theoretical yields. 

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