Yields, calculation theoretical

Table 4. Calculated theoretical yields for mixed coupling products R- R...

From adsorption analysis data, it is possible to calculate theoretical yields of deoiled wax, asphalt, resins, and solvent extraction yields of waxy raffinate. Nearly 100 different stocks have been so evaluated by California Research Corp. during the past few years and many of these data have been correlated with operations in refinery equipment and with pilot plant operations. 

You are given the mass of the reactant AgNOj and the actual yield of the product Ag2Cr04. You need to write the balanced chemical equation and calculate the theoretical yield by making these conversions grams of silver nitrate to moles of silver nitrate, moles of silver nitrate to moles of silver chromate, moles of silver chromate to grams of silver chromate. The percent yield can be calculated from the actual yield of product and the calculated theoretical yield. 

Determine the percentage yield of a reaction from its calculated theoretical yield and its measured actual yield (Section 2.6, Problems 49 and 50). 

Table 4 Calculated Theoretical Yields for Mixed Coupling Reactions Products R —R ...

EXERCISE 3.20 Calculating Theoretical Yield and Percent Yield... 

Students frequently have difficulty in setting up Tables of Reactants and Products and calculating theoretical yields, so two hypothetical examples are provided for your reference. 

The mass of product isolated after a reaction is often less than the mass theoretically possible. The ratio of the ac-tnal isolated mass (actnal yield) to the calculated theoretical yield multiplied by 100 is the percentage yield. Objective 8, Exercise 5.56... 

The actual yield of a reaction was 11.74 g of product, while the calculated theoretical yield was 16.09 g. What was the percentage yield ... 

The theoretical yield has the right units (g AS2S3). The magnitude of e theoretical yield seems reasonable because it is of fhe same order of magnitude as the given masses of As and S. The theoretical yield is reasonable because it is less than 100%. Any calculated theoretical yield above 100% would be suspect. 

Calculating theoretical yield is a typical stoichiometry problem. Solve part (a). 

Strategy Convert reactant grams to moles, rmd determine which is the limiting reactant Use the balanced equation to determine the number of moles of aspirin that can be produced, and convert this number of moles to grams for the theoretical yield. Use the actual yield (given in the problem) and the calculated theoretical yield to calculate the percent yield. 

Calculation of Yield. The yield of a compound obtained in an organic preparation, in addition to being stated in grams, should also be calculated as a percentage of the yield theoretically possible from the weight of the original... 

Let us suppose it is desired to calculate the theoretical yield of ethyl maleate when 33 g. of silver maleate, suspended m dry ether, are treated with the calculated quantity of ethyl iodide (31-2 g.). 

Often you will be given the amounts of two different reactants and asked to determine which is the limiting reactant, to calculate the theoretical yield of the product and to find how much of the excess reactant is unused. To do so, it helps to follow a systematic, four-step procedure. 

Choose the smaller of the two amounts calculated in (1) and (2). This is the theoretical yield of product the reactant that produces the smaller amount is the limiting reactant. The other reactant is in excess only part of it is consumed. 

Remember that in deciding on the theoretical yield of product, you choose the smaller of the two calculated amounts. To see why this must be the case, refer back to Example 3.10b. There 1.20 g of Sb was mixed with 2.40 g of I2. Calculations show that the theoretical yield of Sbl3 is 3.17 g, and 0.43 g of Sb is left over. Thus... 

The theoretical yield is the maximum amount of product that can be obtained. In calculating the theoretical yield, it is assumed that the limiting reactant is 100% converted to product. In the real world, that is unlikely to happen. Some of the limiting reactant may be consumed in competing reactions. Some of the product may be lost in separating it from the reaction mixture. For these and other reasons, the experimental yield is ordinarily less than the theoretical yield. Put another way, the percent yield is expected to be less than 100% ... 

Using these equations it is possible to calculate theoretical values for glucose yield coefficients (Yg). Yg values can be calculated for cell mass, phenylalanine and acetic add and is simply the amount of produd produced per unit amount of glucose consumed. So the theoretical yield of phenylalanine on glucose, for example using equation 8.1, is ... 

To calculate percentage yield, one needs to know the theoretical value that can be obtained, based on material balance, and if 100% of the reactant(s) is converted to product. After obtaining the experimental value (actual yield), divide it by the theoretical value, then multiply by 100 to get percentage yield.8... 

The theoretical yield of a reaction is the maximum quantity (amount, mass, or volume) of product that can be obtained from a given quantity of reactant. The quantities of products calculated from a given mass of reactant in Section L were all theoretical yields. The percentage yield is the fraction of the theoretical yield actually produced, expressed as a percentage ... 

STRATEGY Begin by writing the chemical equation for the complete oxidation of octane to carbon dioxide and water. Then calculate the theoretical yield (in grams) of CO, by using the procedure in Toolbox L.l. To avoid rounding errors, do all the numerical work at the end of the calculation. To obtain the percentage yield, divide the actual I mass produced by the theoretical mass of product and multiply by 100%. 

The limiting reactant is the reactant that will be completely used up. All other reactants are in excess. Because the limiting reactant is the one that limits the amounts of products that can be formed, the theoretical yield is calculated from the amount of the limiting reactant. 

STRATEGY First, the limiting reactant must be identified (Toolbox M.l). This limiting reactant determines the theoretical yield of the reaction, and so we use it to calculate the theoretical amount of product by Method 2 in Toolbox L.l. The percentage yield is the ratio of the mass produced to the theoretical mass times 100. Molar masses are j calculated using the information in the periodic table inside the front cover of this i book. 

Methanol, CH OH, is a clean-burning liquid fuel being considered as a replacement for gasoline. Calculate the theoretical yield in kilograms of C02 produced by the combustion of 1.00 L of methanol (of density 0.791 g-cm ) and compare it with the 2.16 kg of CO, generated by the combustion of 1.00 L. of octane. Which fuel contributes more C02 per liter to the atmosphere when burned What other factors would you take into consideration when deciding which of the two fuels to use See Box 14.2. 

If the percent yield of a reaction is already known, we can calculate how much of a product to expect from a synthesis that uses a known amount of starting material. For example, the Haber synthesis of ammonia stops when 13% of the starting materials have formed products. Knowing this, how much ammonia could an industrial producer expect to make from 2.0 metric tons of molecular hydrogen First, calculate the theoretical yield ... 

C04-0012. When heated, potassium chlorate decomposes to potassium chloride and gaseous molecular oxygen 2 KCIO3 2KC1 + 3 O2 What is the theoretical yield of oxygen when 5.00 g of potassium chlorate decomposes Calculate the percent yield if a 5.00-g sample gives 1.84 g O2 on decomposition. Give possible reasons why the actual yield is less than the theoretical yield. 

A reaction that is carried out under limiting reactant conditions nevertheless has a yield that generally will be less than 100%. The reasons why reactions yield less than the theoretical amounts, given in Section 4-1. apply to all reactions. When a reaction operates under limiting reactant conditions, we calculate the theoretical yield assuming that the limiting reactant will be completely consumed. We then determine the percent yield as described in Section 4A. Example shows how to do this. 

Use fJ = luf V to calculate amounts of each ion present in the two solutions before mixing, and determine which is limiting. Then solve for the theoretical yield, and apply Equation to calculate percent yield. 

The theoretical yield of the method is less than 100%, as only 80 - 90% of the aqueous phase is removed after back-extraction. The actual yield obtained by 54 Mn counting was 69.5 7.8%, and this can be allowed for in the calculation of results. Environmental Protection Agency standard seawater samples of known manganese content (4370 ng/1) gave good manganese recoveries (4260 ng/1). 

Balanced equation PC13 + Cl2 - PC15 Step 1. Calculate the theoretical yield of PC15. 

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