{"id":205,"date":"2021-07-23T09:19:16","date_gmt":"2021-07-23T13:19:16","guid":{"rendered":"https:\/\/pressbooks.bccampus.ca\/aperrott\/chapter\/reaction-yields\/"},"modified":"2022-06-22T09:44:34","modified_gmt":"2022-06-22T13:44:34","slug":"reaction-yields","status":"publish","type":"chapter","link":"https:\/\/pressbooks.bccampus.ca\/aperrott\/chapter\/reaction-yields\/","title":{"raw":"4.4 Reaction Yields","rendered":"4.4 Reaction Yields"},"content":{"raw":"<strong>\u00a0<\/strong>\r\n<div class=\"textbox textbox--learning-objectives\">\r\n<h3><strong>Learning Objectives<\/strong><\/h3>\r\nBy the end of this section, you will be able to:\r\n<ul>\r\n \t<li>Explain the concepts of theoretical yield and limiting reactants\/reagents.<\/li>\r\n \t<li>Derive the theoretical yield for a reaction under specified conditions.<\/li>\r\n \t<li>Calculate the percent yield for a reaction.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<p id=\"fs-idp24998416\">The relative amounts of reactants and products represented in a balanced chemical equation are often referred to as <em data-effect=\"italics\">stoichiometric amounts<\/em>. All the exercises of the preceding module involved stoichiometric amounts of reactants. For example, when calculating the amount of product generated from a given amount of reactant, it was assumed that any other reactants required were available in stoichiometric amounts (or greater). In this module, more realistic situations are considered, in which reactants are not present in stoichiometric amounts.<\/p>\r\n\r\n<div id=\"fs-idp5731792\" class=\"bc-section section\" data-depth=\"1\">\r\n<h3 data-type=\"title\"><strong>Limiting Reactant<\/strong><\/h3>\r\n<p id=\"fs-idp103911360\">Consider another food analogy, making grilled cheese sandwiches (<a class=\"autogenerated-content\" href=\"#CNX_Chem_04_04_sandwich\">(Figure)<\/a>):<\/p>\r\n\r\n<div id=\"fs-idp59817360\" style=\"text-align: center\" data-type=\"equation\">1 slice of cheese + 2 slices of bread \u27f6 1 sandwich<\/div>\r\n<p id=\"fs-idp39531056\">Stoichiometric amounts of sandwich ingredients for this recipe are bread and cheese slices in a 2:1 ratio. Provided with 28 slices of bread and 11 slices of cheese, one may prepare 11 sandwiches per the provided recipe, using all the provided cheese and having six slices of bread left over. In this scenario, the number of sandwiches prepared has been <em data-effect=\"italics\">limited<\/em> by the number of cheese slices, and the bread slices have been provided in <em data-effect=\"italics\">excess<\/em>.<\/p>\r\n&nbsp;\r\n<div id=\"CNX_Chem_04_04_sandwich\" class=\"bc-figure figure\">\r\n<div class=\"bc-figcaption figcaption\">Sandwich making can illustrate the concepts of limiting and excess reactants.<\/div>\r\n<span id=\"fs-idm59912944\" data-type=\"media\" data-alt=\"This figure has three rows showing the ingredients needed to make a sandwich. The first row reads, \u201c1 sandwich = 2 slices of bread + 1 slice of cheese.\u201d Two slices of bread and one slice of cheese are shown. The second row reads, \u201cProvided with: 28 slices of bread + 11 slices of cheese.\u201d There are 28 slices of bread and 11 slices of cheese shown. The third row reads, \u201cWe can make: 11 sandwiches + 6 slices of bread left over.\u201d 11 sandwiches are shown with six extra slices of bread.\"><img src=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/CNX_Chem_04_04_sandwich-1.jpg\" alt=\"This figure has three rows showing the ingredients needed to make a sandwich. The first row reads, \u201c1 sandwich = 2 slices of bread + 1 slice of cheese.\u201d Two slices of bread and one slice of cheese are shown. The second row reads, \u201cProvided with: 28 slices of bread + 11 slices of cheese.\u201d There are 28 slices of bread and 11 slices of cheese shown. The third row reads, \u201cWe can make: 11 sandwiches + 6 slices of bread left over.\u201d 11 sandwiches are shown with six extra slices of bread.\" data-media-type=\"image\/jpeg\" \/><\/span>\r\n\r\n<\/div>\r\n<p id=\"fs-idm48112848\">Consider this concept now with regard to a chemical process, the reaction of hydrogen with chlorine to yield hydrogen chloride:<\/p>\r\n\r\n<div id=\"fs-idp62209424\" style=\"text-align: center\" data-type=\"equation\">H<sub>2<\/sub>(g) + Cl<sub>2<\/sub>(g) \u27f6 2HCl(g)<\/div>\r\n<p id=\"fs-idp157494624\">The balanced equation shows the hydrogen and chlorine react in a 1:1 stoichiometric ratio. If these reactants are provided in any other amounts, one of the reactants will nearly always be entirely consumed, thus limiting the amount of product that may be generated. This substance is the <strong>limiting reactant<\/strong>, and the other substance is the <strong>excess reactant<\/strong>. Identifying the limiting and excess reactants for a given situation requires computing the molar amounts of each reactant provided and comparing them to the stoichiometric amounts represented in the balanced chemical equation. For example, imagine combining 3 moles of H<sub>2<\/sub> and 2 moles of Cl<sub>2<\/sub>. This represents a 3:2 (or 1.5:1) ratio of hydrogen to chlorine present for reaction, which is greater than the stoichiometric ratio of 1:1. Hydrogen, therefore, is present in excess, and chlorine is the limiting reactant. Reaction of all the provided chlorine (2 mol) will consume 2 mol of the 3 mol of hydrogen provided, leaving 1 mol of hydrogen unreacted.<\/p>\r\n<p id=\"fs-idp22005824\">An alternative approach to identifying the limiting reactant involves comparing the amount of product expected for the complete reaction of each reactant. Each reactant amount is used to separately calculate the amount of product that would be formed per the reaction\u2019s stoichiometry. The reactant yielding the lesser amount of product is the limiting reactant. For the example in the previous paragraph, complete reaction of the hydrogen would yield<\/p>\r\n\r\n<div id=\"fs-idp67209632\" data-type=\"equation\"><img class=\"wp-image-1187 aligncenter\" src=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4a-300x46.png\" alt=\"\" width=\"254\" height=\"39\" \/><\/div>\r\n<p id=\"fs-idm20022400\">Complete reaction of the provided chlorine would produce<\/p>\r\n\r\n<div id=\"fs-idp10471024\" data-type=\"equation\"><img class=\"wp-image-1188 aligncenter\" src=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4b-300x43.png\" alt=\"\" width=\"251\" height=\"36\" \/><\/div>\r\n<p id=\"fs-idm39942944\">The chlorine will be completely consumed once 4 moles of HCl have been produced. Since enough hydrogen was provided to yield 6 moles of HCl, there will be unreacted hydrogen remaining once this reaction is complete. Chlorine, therefore, is the limiting reactant and hydrogen is the excess reactant (<a class=\"autogenerated-content\" href=\"#CNX_Chem_04_04_limiting\">(Figure)<\/a>).<\/p>\r\n\r\n<div id=\"CNX_Chem_04_04_limiting\" class=\"bc-figure figure\">\r\n<div><\/div>\r\n<div class=\"bc-figcaption figcaption\">When H<sub>2<\/sub> and Cl<sub>2<\/sub> are combined in nonstoichiometric amounts, one of these reactants will limit the amount of HCl that can be produced. This illustration shows a reaction in which hydrogen is present in excess and chlorine is the limiting reactant.<\/div>\r\n<span id=\"fs-idp182564432\" data-type=\"media\" data-alt=\"The figure shows a space-filling molecular models reacting. There is a reaction arrow pointing to the right in the middle. To the left of the reaction arrow there are three molecules each consisting of two green spheres bonded together. There are also five molecules each consisting of two smaller, white spheres bonded together. Above these molecules is the label, \u201cBefore reaction,\u201d and below these molecules is the label, \u201c6 H subscript 2 and 4 C l subscript 2.\u201d To the right of the reaction arrow, there are eight molecules each consisting of one green sphere bonded to a smaller white sphere. There are also two molecules each consisting of two white spheres bonded together. Above these molecules is the label, \u201cAfter reaction,\u201d and below these molecules is the label, \u201c8 H C l and 2 H subscript 2.\u201d\"><img src=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/CNX_Chem_04_04_limiting-1.jpg\" alt=\"The figure shows a space-filling molecular models reacting. There is a reaction arrow pointing to the right in the middle. To the left of the reaction arrow there are three molecules each consisting of two green spheres bonded together. There are also five molecules each consisting of two smaller, white spheres bonded together. Above these molecules is the label, \u201cBefore reaction,\u201d and below these molecules is the label, \u201c6 H subscript 2 and 4 C l subscript 2.\u201d To the right of the reaction arrow, there are eight molecules each consisting of one green sphere bonded to a smaller white sphere. There are also two molecules each consisting of two white spheres bonded together. Above these molecules is the label, \u201cAfter reaction,\u201d and below these molecules is the label, \u201c8 H C l and 2 H subscript 2.\u201d\" data-media-type=\"image\/jpeg\" \/><\/span>\r\n\r\n<\/div>\r\n<div id=\"fs-idp162031984\" class=\"chemistry link-to-learning\" data-type=\"note\">\r\n<p id=\"fs-idm52028528\">View this interactive <a href=\"http:\/\/openstaxcollege.org\/l\/16reactantprod\">simulation<\/a> illustrating the concepts of limiting and excess reactants.<\/p>\r\n\r\n<\/div>\r\n<div id=\"fs-idp70587344\" class=\"textbox textbox--examples\" data-type=\"example\">\r\n<p id=\"fs-idm3583984\"><strong>Identifying the Limiting Reactant:<\/strong><\/p>\r\nSilicon nitride is a very hard, high-temperature-resistant ceramic used as a component of turbine blades in jet engines. It is prepared according to the following equation:\r\n<div id=\"fs-idm22587536\" style=\"text-align: center\" data-type=\"equation\">3Si(<em>s<\/em>) + 2N<sub>2<\/sub>(<em>g<\/em>) \u27f6 Si<sub>3<\/sub>N<sub>4<\/sub>(<em>s<\/em>)<\/div>\r\n<div data-type=\"equation\"><\/div>\r\n<p id=\"fs-idp52711328\">Which is the limiting reactant when 2.00 g of Si and 1.50 g of N<sub>2<\/sub> react?<\/p>\r\n<p id=\"fs-idm18749312\"><strong>Solution:<\/strong><\/p>\r\nCompute the provided molar amounts of reactants, and then compare these amounts to the balanced equation to identify the limiting reactant.\r\n\r\n<img class=\"size-medium wp-image-1190 aligncenter\" src=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4c-300x126.png\" alt=\"\" width=\"300\" height=\"126\" \/>\r\n<p id=\"fs-idp47057824\">The provided Si:N<sub>2<\/sub> molar ratio is:<\/p>\r\n\r\n<div id=\"fs-idp107313360\" data-type=\"equation\"><img class=\"wp-image-1191 aligncenter\" src=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4d-300x72.png\" alt=\"\" width=\"238\" height=\"57\" \/><\/div>\r\n<p id=\"fs-idm100978944\">The stoichiometric Si:N<sub>2<\/sub> ratio is:<\/p>\r\n\r\n<div id=\"fs-idm60202256\" data-type=\"equation\"><img class=\"wp-image-1192 aligncenter\" src=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4e.png\" alt=\"\" width=\"210\" height=\"53\" \/><\/div>\r\n<p id=\"fs-idm1915936\">Comparing these ratios shows that Si is provided in a less-than-stoichiometric amount, and so is the limiting reactant.<\/p>\r\n<p id=\"fs-idm9495168\">Alternatively, compute the amount of product expected for complete reaction of each of the provided reactants. The 0.0712 moles of silicon would yield<\/p>\r\n\r\n<div id=\"fs-idp161973712\" data-type=\"equation\"><img class=\"wp-image-1193 aligncenter\" src=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4f-300x32.png\" alt=\"\" width=\"338\" height=\"36\" \/><\/div>\r\n<div data-type=\"equation\"><\/div>\r\n<p id=\"fs-idm3691696\">while the 0.0535 moles of nitrogen would produce<\/p>\r\n\r\n<div id=\"fs-idm62043536\" data-type=\"equation\"><img class=\" wp-image-1194 aligncenter\" src=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4g-300x36.png\" alt=\"\" width=\"333\" height=\"40\" \/><\/div>\r\n<div data-type=\"equation\"><\/div>\r\n<p id=\"fs-idm55343248\">Since silicon yields the lesser amount of product, it is the limiting reactant.<\/p>\r\n<p id=\"fs-idp70544208\"><span data-type=\"title\"><strong>Check Your Learning:<\/strong>\r\n<\/span> Which is the limiting reactant when 5.00 g of H<sub>2<\/sub> and 10.0 g of O<sub>2<\/sub> react and form water?<\/p>\r\n&nbsp;\r\n<div id=\"fs-idm19095728\" data-type=\"note\">\r\n<div data-type=\"title\"><strong>Answer:<\/strong><\/div>\r\n<p id=\"fs-idp69025056\">O<sub>2<\/sub><\/p>\r\n\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n<div id=\"fs-idm20935792\" class=\"bc-section section\" data-depth=\"1\">\r\n<h3 data-type=\"title\"><strong>Percent Yield<\/strong><\/h3>\r\n<p id=\"fs-idm22072192\">The amount of product that <em data-effect=\"italics\">may be<\/em> produced by a reaction under specified conditions, as calculated per the stoichiometry of an appropriate balanced chemical equation, is called the <strong>theoretical yield<\/strong> of the reaction. In practice, the amount of product obtained is called the <strong>actual yield<\/strong>, and it is often less than the theoretical yield for a number of reasons. Some reactions are inherently inefficient, being accompanied by <em data-effect=\"italics\">side reactions<\/em> that generate other products. Others are, by nature, incomplete (consider the partial reactions of weak acids and bases discussed earlier in this chapter). Some products are difficult to collect without some loss, and so less than perfect recovery will reduce the actual yield. The extent to which a reaction\u2019s theoretical yield is achieved is commonly expressed as its <strong>percent yield<\/strong>:<strong><img class=\"alignnone wp-image-1195 aligncenter\" src=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4h-300x44.png\" alt=\"\" width=\"314\" height=\"46\" \/><\/strong><\/p>\r\n<p id=\"fs-idm52282816\">Actual and theoretical yields may be expressed as masses or molar amounts (or any other appropriate property; e.g., volume, if the product is a gas). As long as both yields are expressed using the same units, these units will cancel when percent yield is calculated.<\/p>\r\n\r\n<div id=\"fs-idm49018784\" class=\"textbox textbox--examples\" data-type=\"example\">\r\n<p id=\"fs-idm68646768\"><strong>Calculation of Percent Yield:<\/strong><\/p>\r\nUpon reaction of 1.274 g of copper sulfate with excess zinc metal, 0.392 g copper metal was obtained according to the equation:\r\n<div id=\"fs-idp101757552\" style=\"text-align: center\" data-type=\"equation\">CuSO<sub>4<\/sub>(<em>aq<\/em>) + Zn(<em>s<\/em>) \u27f6 Cu(<em>s<\/em>) + ZnSO<sub>4<\/sub>(<sub>aq<\/sub>)<\/div>\r\n<div data-type=\"equation\"><\/div>\r\n<p id=\"fs-idp104261712\">What is the percent yield?<\/p>\r\n<p id=\"fs-idp98890704\"><strong>Solution:<\/strong><\/p>\r\nThe provided information identifies copper sulfate as the limiting reactant, and so the theoretical yield is found by the approach illustrated in the previous module, as shown here:\r\n<div id=\"fs-idp104521856\" data-type=\"equation\"><img class=\"wp-image-1196 aligncenter\" src=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4i-300x31.png\" alt=\"\" width=\"494\" height=\"51\" \/><\/div>\r\n<div data-type=\"equation\"><\/div>\r\n<p id=\"fs-idp47540336\">Using this theoretical yield and the provided value for actual yield, the percent yield is calculated to be<\/p>\r\n<img class=\"wp-image-1197 aligncenter\" src=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4j-300x144.png\" alt=\"\" width=\"331\" height=\"159\" \/>\r\n\r\n<\/div>\r\n<div class=\"textbox textbox--examples\" data-type=\"example\">\r\n<p id=\"fs-idp38988928\"><strong>Check Your Learning:<\/strong><\/p>\r\nWhat is the percent yield of a reaction that produces 12.5 g of the gas Freon CF<sub>2<\/sub>Cl<sub>2<\/sub> from 32.9 g of CCl<sub>4<\/sub> and excess HF?\r\n<div id=\"fs-idp61435552\" style=\"text-align: center\" data-type=\"equation\">CCl<sub>4<\/sub> + 2HF \u27f6 CF<sub>2<\/sub>Cl<sub>2<\/sub> + 2HCl<\/div>\r\n<div data-type=\"equation\"><\/div>\r\n<div id=\"fs-idp47749920\" data-type=\"note\">\r\n<div data-type=\"title\"><strong>Answer:<\/strong><\/div>\r\n<p id=\"fs-idp47655136\">48.3%<\/p>\r\n\r\n<\/div>\r\n<\/div>\r\n<div id=\"fs-idm21958480\" class=\"chemistry sciences-interconnect\" data-type=\"note\">\r\n<div data-type=\"title\"><\/div>\r\n<div data-type=\"title\"><strong>Green Chemistry and Atom Economy<\/strong><\/div>\r\n<p id=\"fs-idm49080288\">The purposeful design of chemical products and processes that minimize the use of environmentally hazardous substances and the generation of waste is known as <em data-effect=\"italics\">green chemistry<\/em>. Green chemistry is a philosophical approach that is being applied to many areas of science and technology, and its practice is summarized by guidelines known as the \u201cTwelve Principles of Green Chemistry\u201d (see details at this <a href=\"http:\/\/openstaxcollege.org\/l\/16greenchem\">website<\/a>). One of the 12 principles is aimed specifically at maximizing the efficiency of processes for synthesizing chemical products. The <em data-effect=\"italics\">atom economy<\/em> of a process is a measure of this efficiency, defined as the percentage by mass of the final product of a synthesis relative to the masses of <em data-effect=\"italics\">all<\/em> the reactants used:<\/p>\r\n\r\n<div id=\"fs-idp116950848\" data-type=\"equation\"><img class=\"wp-image-1198 aligncenter\" src=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4k-300x41.png\" alt=\"\" width=\"351\" height=\"48\" \/><\/div>\r\n<p id=\"fs-idp59920960\">Though the definition of atom economy at first glance appears very similar to that for percent yield, be aware that this property represents a difference in the <em data-effect=\"italics\">theoretical<\/em> efficiencies of <em data-effect=\"italics\">different<\/em> chemical processes. The percent yield of a given chemical process, on the other hand, evaluates the efficiency of a process by comparing the yield of product actually obtained to the maximum yield predicted by stoichiometry.<\/p>\r\n<p id=\"fs-idp167996000\">The synthesis of the common nonprescription pain medication, ibuprofen, nicely illustrates the success of a green chemistry approach (<a class=\"autogenerated-content\" href=\"#CNX_Chem_04_04_GreenChem\">(Figure)<\/a>). First marketed in the early 1960s, ibuprofen was produced using a six-step synthesis that required 514 g of reactants to generate each mole (206 g) of ibuprofen, an atom economy of 40%. In the 1990s, an alternative process was developed by the BHC Company (now BASF Corporation) that requires only three steps and has an atom economy of ~80%, nearly twice that of the original process. The BHC process generates significantly less chemical waste; uses less-hazardous and recyclable materials; and provides significant cost-savings to the manufacturer (and, subsequently, the consumer). In recognition of the positive environmental impact of the BHC process, the company received the Environmental Protection Agency\u2019s Greener Synthetic Pathways Award in 1997.<\/p>\r\n&nbsp;\r\n<div id=\"CNX_Chem_04_04_GreenChem\" class=\"scaled-down\">\r\n<div class=\"bc-figcaption figcaption\">(a) Ibuprofen is a popular nonprescription pain medication commonly sold as 200 mg tablets. (b) The BHC process for synthesizing ibuprofen requires only three steps and exhibits an impressive atom economy. (credit a: modification of work by Derrick Coetzee)<\/div>\r\n<span id=\"fs-idp994368\" data-type=\"media\" data-alt=\"This figure is labeled, \u201ca,\u201d and, \u201cb.\u201d Part a shows an open bottle of ibuprofen and a small pile of ibuprofen tablets beside it. Part b shows a reaction along with line structures. The first line structure looks like a diagonal line pointing down and to the right, then up and to the right and then down and to the right. At this point it connects to a hexagon with alternating double bonds. At the first trough there is a line that points straight down. From this structure, there is an arrow pointing downward. The arrow is labeled, \u201cH F,\u201d on the left and \u201c( C H subscript 3 C O ) subscript 2 O,\u201d on the right. The next line structure looks exactly like the first line structure, but it has a line angled down and to the right from the lower right point of the hexagon. This line is connected to another line which points straight down. Where these two lines meet, there is a double bond to an O atom. There is another arrow pointing downward, and it is labeled, \u201cH subscript 2, Raney N i.\u201d The next structure looks very similar to the second, previous structure, except in place of the double bonded O, there is a singly bonded O H group. There is a final reaction arrow pointing downward, and it is labeled, \u201cC O, [ P d ].\u201d The final structure is similar to the third, previous structure except in place of the O H group, there is another line that points down and to the right to an O H group. At these two lines, there is a double bonded O.\"><img src=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/CNX_Chem_04_04_GreenChem-1.jpg\" alt=\"This figure is labeled, \u201ca,\u201d and, \u201cb.\u201d Part a shows an open bottle of ibuprofen and a small pile of ibuprofen tablets beside it. Part b shows a reaction along with line structures. The first line structure looks like a diagonal line pointing down and to the right, then up and to the right and then down and to the right. At this point it connects to a hexagon with alternating double bonds. At the first trough there is a line that points straight down. From this structure, there is an arrow pointing downward. The arrow is labeled, \u201cH F,\u201d on the left and \u201c( C H subscript 3 C O ) subscript 2 O,\u201d on the right. The next line structure looks exactly like the first line structure, but it has a line angled down and to the right from the lower right point of the hexagon. This line is connected to another line which points straight down. Where these two lines meet, there is a double bond to an O atom. There is another arrow pointing downward, and it is labeled, \u201cH subscript 2, Raney N i.\u201d The next structure looks very similar to the second, previous structure, except in place of the double bonded O, there is a singly bonded O H group. There is a final reaction arrow pointing downward, and it is labeled, \u201cC O, [ P d ].\u201d The final structure is similar to the third, previous structure except in place of the O H group, there is another line that points down and to the right to an O H group. At these two lines, there is a double bonded O.\" data-media-type=\"image\/jpeg\" \/><\/span>\r\n\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n<div id=\"fs-idm64875168\" class=\"summary\" data-depth=\"1\">\r\n<h3 data-type=\"title\"><strong>Key Concepts and Summary<\/strong><\/h3>\r\n<p id=\"fs-idm5314032\">When reactions are carried out using less-than-stoichiometric quantities of reactants, the amount of product generated will be determined by the limiting reactant. The amount of product generated by a chemical reaction is its actual yield. This yield is often less than the amount of product predicted by the stoichiometry of the balanced chemical equation representing the reaction (its theoretical yield). The extent to which a reaction generates the theoretical amount of product is expressed as its percent yield.<\/p>\r\n\r\n<\/div>\r\n<div id=\"fs-idm49138160\" class=\"exercises\" data-depth=\"1\">\r\n<div id=\"fs-idm19471568\" data-type=\"exercise\">\r\n<div id=\"fs-idp17552400\" data-type=\"solution\">\r\n<p id=\"fs-idp8960064\"><\/p>\r\n\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n<div class=\"textbox shaded\" data-type=\"glossary\">\r\n<h3 data-type=\"glossary-title\"><strong>Glossary<\/strong><\/h3>\r\n<dl id=\"fs-idm47393392\">\r\n \t<dt>actual yield<\/dt>\r\n \t<dd id=\"fs-idp169189008\">amount of product formed in a reaction<\/dd>\r\n<\/dl>\r\n<dl id=\"fs-idm46343008\">\r\n \t<dt>excess reactant<\/dt>\r\n \t<dd id=\"fs-idp169769328\">reactant present in an amount greater than required by the reaction stoichiometry<\/dd>\r\n<\/dl>\r\n<dl id=\"fs-idp182610272\">\r\n \t<dt>limiting reactant<\/dt>\r\n \t<dd id=\"fs-idp67500512\">reactant present in an amount lower than required by the reaction stoichiometry, thus limiting the amount of product generated<\/dd>\r\n<\/dl>\r\n<dl id=\"fs-idp51447712\">\r\n \t<dt>percent yield<\/dt>\r\n \t<dd id=\"fs-idp172539984\">measure of the efficiency of a reaction, expressed as a percentage of the theoretical yield<\/dd>\r\n<\/dl>\r\n<dl id=\"fs-idp30967968\">\r\n \t<dt>theoretical yield<\/dt>\r\n \t<dd id=\"fs-idm94035648\">amount of product that may be produced from a given amount of reactant(s) according to the reaction stoichiometry<\/dd>\r\n<\/dl>\r\n<\/div>","rendered":"<p><strong>\u00a0<\/strong><\/p>\n<div class=\"textbox textbox--learning-objectives\">\n<h3><strong>Learning Objectives<\/strong><\/h3>\n<p>By the end of this section, you will be able to:<\/p>\n<ul>\n<li>Explain the concepts of theoretical yield and limiting reactants\/reagents.<\/li>\n<li>Derive the theoretical yield for a reaction under specified conditions.<\/li>\n<li>Calculate the percent yield for a reaction.<\/li>\n<\/ul>\n<\/div>\n<p id=\"fs-idp24998416\">The relative amounts of reactants and products represented in a balanced chemical equation are often referred to as <em data-effect=\"italics\">stoichiometric amounts<\/em>. All the exercises of the preceding module involved stoichiometric amounts of reactants. For example, when calculating the amount of product generated from a given amount of reactant, it was assumed that any other reactants required were available in stoichiometric amounts (or greater). In this module, more realistic situations are considered, in which reactants are not present in stoichiometric amounts.<\/p>\n<div id=\"fs-idp5731792\" class=\"bc-section section\" data-depth=\"1\">\n<h3 data-type=\"title\"><strong>Limiting Reactant<\/strong><\/h3>\n<p id=\"fs-idp103911360\">Consider another food analogy, making grilled cheese sandwiches (<a class=\"autogenerated-content\" href=\"#CNX_Chem_04_04_sandwich\">(Figure)<\/a>):<\/p>\n<div id=\"fs-idp59817360\" style=\"text-align: center\" data-type=\"equation\">1 slice of cheese + 2 slices of bread \u27f6 1 sandwich<\/div>\n<p id=\"fs-idp39531056\">Stoichiometric amounts of sandwich ingredients for this recipe are bread and cheese slices in a 2:1 ratio. Provided with 28 slices of bread and 11 slices of cheese, one may prepare 11 sandwiches per the provided recipe, using all the provided cheese and having six slices of bread left over. In this scenario, the number of sandwiches prepared has been <em data-effect=\"italics\">limited<\/em> by the number of cheese slices, and the bread slices have been provided in <em data-effect=\"italics\">excess<\/em>.<\/p>\n<p>&nbsp;<\/p>\n<div id=\"CNX_Chem_04_04_sandwich\" class=\"bc-figure figure\">\n<div class=\"bc-figcaption figcaption\">Sandwich making can illustrate the concepts of limiting and excess reactants.<\/div>\n<p><span id=\"fs-idm59912944\" data-type=\"media\" data-alt=\"This figure has three rows showing the ingredients needed to make a sandwich. The first row reads, \u201c1 sandwich = 2 slices of bread + 1 slice of cheese.\u201d Two slices of bread and one slice of cheese are shown. The second row reads, \u201cProvided with: 28 slices of bread + 11 slices of cheese.\u201d There are 28 slices of bread and 11 slices of cheese shown. The third row reads, \u201cWe can make: 11 sandwiches + 6 slices of bread left over.\u201d 11 sandwiches are shown with six extra slices of bread.\"><img decoding=\"async\" src=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/CNX_Chem_04_04_sandwich-1.jpg\" alt=\"This figure has three rows showing the ingredients needed to make a sandwich. The first row reads, \u201c1 sandwich = 2 slices of bread + 1 slice of cheese.\u201d Two slices of bread and one slice of cheese are shown. The second row reads, \u201cProvided with: 28 slices of bread + 11 slices of cheese.\u201d There are 28 slices of bread and 11 slices of cheese shown. The third row reads, \u201cWe can make: 11 sandwiches + 6 slices of bread left over.\u201d 11 sandwiches are shown with six extra slices of bread.\" data-media-type=\"image\/jpeg\" \/><\/span><\/p>\n<\/div>\n<p id=\"fs-idm48112848\">Consider this concept now with regard to a chemical process, the reaction of hydrogen with chlorine to yield hydrogen chloride:<\/p>\n<div id=\"fs-idp62209424\" style=\"text-align: center\" data-type=\"equation\">H<sub>2<\/sub>(g) + Cl<sub>2<\/sub>(g) \u27f6 2HCl(g)<\/div>\n<p id=\"fs-idp157494624\">The balanced equation shows the hydrogen and chlorine react in a 1:1 stoichiometric ratio. If these reactants are provided in any other amounts, one of the reactants will nearly always be entirely consumed, thus limiting the amount of product that may be generated. This substance is the <strong>limiting reactant<\/strong>, and the other substance is the <strong>excess reactant<\/strong>. Identifying the limiting and excess reactants for a given situation requires computing the molar amounts of each reactant provided and comparing them to the stoichiometric amounts represented in the balanced chemical equation. For example, imagine combining 3 moles of H<sub>2<\/sub> and 2 moles of Cl<sub>2<\/sub>. This represents a 3:2 (or 1.5:1) ratio of hydrogen to chlorine present for reaction, which is greater than the stoichiometric ratio of 1:1. Hydrogen, therefore, is present in excess, and chlorine is the limiting reactant. Reaction of all the provided chlorine (2 mol) will consume 2 mol of the 3 mol of hydrogen provided, leaving 1 mol of hydrogen unreacted.<\/p>\n<p id=\"fs-idp22005824\">An alternative approach to identifying the limiting reactant involves comparing the amount of product expected for the complete reaction of each reactant. Each reactant amount is used to separately calculate the amount of product that would be formed per the reaction\u2019s stoichiometry. The reactant yielding the lesser amount of product is the limiting reactant. For the example in the previous paragraph, complete reaction of the hydrogen would yield<\/p>\n<div id=\"fs-idp67209632\" data-type=\"equation\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-1187 aligncenter\" src=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4a-300x46.png\" alt=\"\" width=\"254\" height=\"39\" srcset=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4a-300x46.png 300w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4a-65x10.png 65w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4a-225x35.png 225w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4a-350x54.png 350w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4a.png 427w\" sizes=\"auto, (max-width: 254px) 100vw, 254px\" \/><\/div>\n<p id=\"fs-idm20022400\">Complete reaction of the provided chlorine would produce<\/p>\n<div id=\"fs-idp10471024\" data-type=\"equation\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-1188 aligncenter\" src=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4b-300x43.png\" alt=\"\" width=\"251\" height=\"36\" srcset=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4b-300x43.png 300w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4b-65x9.png 65w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4b-225x32.png 225w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4b-350x50.png 350w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4b.png 416w\" sizes=\"auto, (max-width: 251px) 100vw, 251px\" \/><\/div>\n<p id=\"fs-idm39942944\">The chlorine will be completely consumed once 4 moles of HCl have been produced. Since enough hydrogen was provided to yield 6 moles of HCl, there will be unreacted hydrogen remaining once this reaction is complete. Chlorine, therefore, is the limiting reactant and hydrogen is the excess reactant (<a class=\"autogenerated-content\" href=\"#CNX_Chem_04_04_limiting\">(Figure)<\/a>).<\/p>\n<div id=\"CNX_Chem_04_04_limiting\" class=\"bc-figure figure\">\n<div><\/div>\n<div class=\"bc-figcaption figcaption\">When H<sub>2<\/sub> and Cl<sub>2<\/sub> are combined in nonstoichiometric amounts, one of these reactants will limit the amount of HCl that can be produced. This illustration shows a reaction in which hydrogen is present in excess and chlorine is the limiting reactant.<\/div>\n<p><span id=\"fs-idp182564432\" data-type=\"media\" data-alt=\"The figure shows a space-filling molecular models reacting. There is a reaction arrow pointing to the right in the middle. To the left of the reaction arrow there are three molecules each consisting of two green spheres bonded together. There are also five molecules each consisting of two smaller, white spheres bonded together. Above these molecules is the label, \u201cBefore reaction,\u201d and below these molecules is the label, \u201c6 H subscript 2 and 4 C l subscript 2.\u201d To the right of the reaction arrow, there are eight molecules each consisting of one green sphere bonded to a smaller white sphere. There are also two molecules each consisting of two white spheres bonded together. Above these molecules is the label, \u201cAfter reaction,\u201d and below these molecules is the label, \u201c8 H C l and 2 H subscript 2.\u201d\"><img decoding=\"async\" src=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/CNX_Chem_04_04_limiting-1.jpg\" alt=\"The figure shows a space-filling molecular models reacting. There is a reaction arrow pointing to the right in the middle. To the left of the reaction arrow there are three molecules each consisting of two green spheres bonded together. There are also five molecules each consisting of two smaller, white spheres bonded together. Above these molecules is the label, \u201cBefore reaction,\u201d and below these molecules is the label, \u201c6 H subscript 2 and 4 C l subscript 2.\u201d To the right of the reaction arrow, there are eight molecules each consisting of one green sphere bonded to a smaller white sphere. There are also two molecules each consisting of two white spheres bonded together. Above these molecules is the label, \u201cAfter reaction,\u201d and below these molecules is the label, \u201c8 H C l and 2 H subscript 2.\u201d\" data-media-type=\"image\/jpeg\" \/><\/span><\/p>\n<\/div>\n<div id=\"fs-idp162031984\" class=\"chemistry link-to-learning\" data-type=\"note\">\n<p id=\"fs-idm52028528\">View this interactive <a href=\"http:\/\/openstaxcollege.org\/l\/16reactantprod\">simulation<\/a> illustrating the concepts of limiting and excess reactants.<\/p>\n<\/div>\n<div id=\"fs-idp70587344\" class=\"textbox textbox--examples\" data-type=\"example\">\n<p id=\"fs-idm3583984\"><strong>Identifying the Limiting Reactant:<\/strong><\/p>\n<p>Silicon nitride is a very hard, high-temperature-resistant ceramic used as a component of turbine blades in jet engines. It is prepared according to the following equation:<\/p>\n<div id=\"fs-idm22587536\" style=\"text-align: center\" data-type=\"equation\">3Si(<em>s<\/em>) + 2N<sub>2<\/sub>(<em>g<\/em>) \u27f6 Si<sub>3<\/sub>N<sub>4<\/sub>(<em>s<\/em>)<\/div>\n<div data-type=\"equation\"><\/div>\n<p id=\"fs-idp52711328\">Which is the limiting reactant when 2.00 g of Si and 1.50 g of N<sub>2<\/sub> react?<\/p>\n<p id=\"fs-idm18749312\"><strong>Solution:<\/strong><\/p>\n<p>Compute the provided molar amounts of reactants, and then compare these amounts to the balanced equation to identify the limiting reactant.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-1190 aligncenter\" src=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4c-300x126.png\" alt=\"\" width=\"300\" height=\"126\" srcset=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4c-300x126.png 300w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4c-65x27.png 65w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4c-225x94.png 225w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4c-350x147.png 350w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4c.png 470w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/p>\n<p id=\"fs-idp47057824\">The provided Si:N<sub>2<\/sub> molar ratio is:<\/p>\n<div id=\"fs-idp107313360\" data-type=\"equation\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-1191 aligncenter\" src=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4d-300x72.png\" alt=\"\" width=\"238\" height=\"57\" srcset=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4d-300x72.png 300w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4d-65x16.png 65w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4d-225x54.png 225w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4d.png 342w\" sizes=\"auto, (max-width: 238px) 100vw, 238px\" \/><\/div>\n<p id=\"fs-idm100978944\">The stoichiometric Si:N<sub>2<\/sub> ratio is:<\/p>\n<div id=\"fs-idm60202256\" data-type=\"equation\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-1192 aligncenter\" src=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4e.png\" alt=\"\" width=\"210\" height=\"53\" srcset=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4e.png 273w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4e-65x16.png 65w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4e-225x57.png 225w\" sizes=\"auto, (max-width: 210px) 100vw, 210px\" \/><\/div>\n<p id=\"fs-idm1915936\">Comparing these ratios shows that Si is provided in a less-than-stoichiometric amount, and so is the limiting reactant.<\/p>\n<p id=\"fs-idm9495168\">Alternatively, compute the amount of product expected for complete reaction of each of the provided reactants. The 0.0712 moles of silicon would yield<\/p>\n<div id=\"fs-idp161973712\" data-type=\"equation\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-1193 aligncenter\" src=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4f-300x32.png\" alt=\"\" width=\"338\" height=\"36\" srcset=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4f-300x32.png 300w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4f-65x7.png 65w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4f-225x24.png 225w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4f-350x38.png 350w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4f.png 554w\" sizes=\"auto, (max-width: 338px) 100vw, 338px\" \/><\/div>\n<div data-type=\"equation\"><\/div>\n<p id=\"fs-idm3691696\">while the 0.0535 moles of nitrogen would produce<\/p>\n<div id=\"fs-idm62043536\" data-type=\"equation\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-1194 aligncenter\" src=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4g-300x36.png\" alt=\"\" width=\"333\" height=\"40\" srcset=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4g-300x36.png 300w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4g-65x8.png 65w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4g-225x27.png 225w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4g-350x42.png 350w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4g.png 560w\" sizes=\"auto, (max-width: 333px) 100vw, 333px\" \/><\/div>\n<div data-type=\"equation\"><\/div>\n<p id=\"fs-idm55343248\">Since silicon yields the lesser amount of product, it is the limiting reactant.<\/p>\n<p id=\"fs-idp70544208\"><span data-type=\"title\"><strong>Check Your Learning:<\/strong><br \/>\n<\/span> Which is the limiting reactant when 5.00 g of H<sub>2<\/sub> and 10.0 g of O<sub>2<\/sub> react and form water?<\/p>\n<p>&nbsp;<\/p>\n<div id=\"fs-idm19095728\" data-type=\"note\">\n<div data-type=\"title\"><strong>Answer:<\/strong><\/div>\n<p id=\"fs-idp69025056\">O<sub>2<\/sub><\/p>\n<\/div>\n<\/div>\n<\/div>\n<div id=\"fs-idm20935792\" class=\"bc-section section\" data-depth=\"1\">\n<h3 data-type=\"title\"><strong>Percent Yield<\/strong><\/h3>\n<p id=\"fs-idm22072192\">The amount of product that <em data-effect=\"italics\">may be<\/em> produced by a reaction under specified conditions, as calculated per the stoichiometry of an appropriate balanced chemical equation, is called the <strong>theoretical yield<\/strong> of the reaction. In practice, the amount of product obtained is called the <strong>actual yield<\/strong>, and it is often less than the theoretical yield for a number of reasons. Some reactions are inherently inefficient, being accompanied by <em data-effect=\"italics\">side reactions<\/em> that generate other products. Others are, by nature, incomplete (consider the partial reactions of weak acids and bases discussed earlier in this chapter). Some products are difficult to collect without some loss, and so less than perfect recovery will reduce the actual yield. The extent to which a reaction\u2019s theoretical yield is achieved is commonly expressed as its <strong>percent yield<\/strong>:<strong><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-1195 aligncenter\" src=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4h-300x44.png\" alt=\"\" width=\"314\" height=\"46\" srcset=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4h-300x44.png 300w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4h-65x10.png 65w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4h-225x33.png 225w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4h-350x51.png 350w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4h.png 491w\" sizes=\"auto, (max-width: 314px) 100vw, 314px\" \/><\/strong><\/p>\n<p id=\"fs-idm52282816\">Actual and theoretical yields may be expressed as masses or molar amounts (or any other appropriate property; e.g., volume, if the product is a gas). As long as both yields are expressed using the same units, these units will cancel when percent yield is calculated.<\/p>\n<div id=\"fs-idm49018784\" class=\"textbox textbox--examples\" data-type=\"example\">\n<p id=\"fs-idm68646768\"><strong>Calculation of Percent Yield:<\/strong><\/p>\n<p>Upon reaction of 1.274 g of copper sulfate with excess zinc metal, 0.392 g copper metal was obtained according to the equation:<\/p>\n<div id=\"fs-idp101757552\" style=\"text-align: center\" data-type=\"equation\">CuSO<sub>4<\/sub>(<em>aq<\/em>) + Zn(<em>s<\/em>) \u27f6 Cu(<em>s<\/em>) + ZnSO<sub>4<\/sub>(<sub>aq<\/sub>)<\/div>\n<div data-type=\"equation\"><\/div>\n<p id=\"fs-idp104261712\">What is the percent yield?<\/p>\n<p id=\"fs-idp98890704\"><strong>Solution:<\/strong><\/p>\n<p>The provided information identifies copper sulfate as the limiting reactant, and so the theoretical yield is found by the approach illustrated in the previous module, as shown here:<\/p>\n<div id=\"fs-idp104521856\" data-type=\"equation\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-1196 aligncenter\" src=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4i-300x31.png\" alt=\"\" width=\"494\" height=\"51\" srcset=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4i-300x31.png 300w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4i-768x79.png 768w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4i-65x7.png 65w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4i-225x23.png 225w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4i-350x36.png 350w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4i.png 942w\" sizes=\"auto, (max-width: 494px) 100vw, 494px\" \/><\/div>\n<div data-type=\"equation\"><\/div>\n<p id=\"fs-idp47540336\">Using this theoretical yield and the provided value for actual yield, the percent yield is calculated to be<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-1197 aligncenter\" src=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4j-300x144.png\" alt=\"\" width=\"331\" height=\"159\" srcset=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4j-300x144.png 300w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4j-65x31.png 65w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4j-225x108.png 225w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4j-350x168.png 350w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4j.png 496w\" sizes=\"auto, (max-width: 331px) 100vw, 331px\" \/><\/p>\n<\/div>\n<div class=\"textbox textbox--examples\" data-type=\"example\">\n<p id=\"fs-idp38988928\"><strong>Check Your Learning:<\/strong><\/p>\n<p>What is the percent yield of a reaction that produces 12.5 g of the gas Freon CF<sub>2<\/sub>Cl<sub>2<\/sub> from 32.9 g of CCl<sub>4<\/sub> and excess HF?<\/p>\n<div id=\"fs-idp61435552\" style=\"text-align: center\" data-type=\"equation\">CCl<sub>4<\/sub> + 2HF \u27f6 CF<sub>2<\/sub>Cl<sub>2<\/sub> + 2HCl<\/div>\n<div data-type=\"equation\"><\/div>\n<div id=\"fs-idp47749920\" data-type=\"note\">\n<div data-type=\"title\"><strong>Answer:<\/strong><\/div>\n<p id=\"fs-idp47655136\">48.3%<\/p>\n<\/div>\n<\/div>\n<div id=\"fs-idm21958480\" class=\"chemistry sciences-interconnect\" data-type=\"note\">\n<div data-type=\"title\"><\/div>\n<div data-type=\"title\"><strong>Green Chemistry and Atom Economy<\/strong><\/div>\n<p id=\"fs-idm49080288\">The purposeful design of chemical products and processes that minimize the use of environmentally hazardous substances and the generation of waste is known as <em data-effect=\"italics\">green chemistry<\/em>. Green chemistry is a philosophical approach that is being applied to many areas of science and technology, and its practice is summarized by guidelines known as the \u201cTwelve Principles of Green Chemistry\u201d (see details at this <a href=\"http:\/\/openstaxcollege.org\/l\/16greenchem\">website<\/a>). One of the 12 principles is aimed specifically at maximizing the efficiency of processes for synthesizing chemical products. The <em data-effect=\"italics\">atom economy<\/em> of a process is a measure of this efficiency, defined as the percentage by mass of the final product of a synthesis relative to the masses of <em data-effect=\"italics\">all<\/em> the reactants used:<\/p>\n<div id=\"fs-idp116950848\" data-type=\"equation\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-1198 aligncenter\" src=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4k-300x41.png\" alt=\"\" width=\"351\" height=\"48\" srcset=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4k-300x41.png 300w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4k-65x9.png 65w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4k-225x31.png 225w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4k-350x48.png 350w, https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/4.4k.png 505w\" sizes=\"auto, (max-width: 351px) 100vw, 351px\" \/><\/div>\n<p id=\"fs-idp59920960\">Though the definition of atom economy at first glance appears very similar to that for percent yield, be aware that this property represents a difference in the <em data-effect=\"italics\">theoretical<\/em> efficiencies of <em data-effect=\"italics\">different<\/em> chemical processes. The percent yield of a given chemical process, on the other hand, evaluates the efficiency of a process by comparing the yield of product actually obtained to the maximum yield predicted by stoichiometry.<\/p>\n<p id=\"fs-idp167996000\">The synthesis of the common nonprescription pain medication, ibuprofen, nicely illustrates the success of a green chemistry approach (<a class=\"autogenerated-content\" href=\"#CNX_Chem_04_04_GreenChem\">(Figure)<\/a>). First marketed in the early 1960s, ibuprofen was produced using a six-step synthesis that required 514 g of reactants to generate each mole (206 g) of ibuprofen, an atom economy of 40%. In the 1990s, an alternative process was developed by the BHC Company (now BASF Corporation) that requires only three steps and has an atom economy of ~80%, nearly twice that of the original process. The BHC process generates significantly less chemical waste; uses less-hazardous and recyclable materials; and provides significant cost-savings to the manufacturer (and, subsequently, the consumer). In recognition of the positive environmental impact of the BHC process, the company received the Environmental Protection Agency\u2019s Greener Synthetic Pathways Award in 1997.<\/p>\n<p>&nbsp;<\/p>\n<div id=\"CNX_Chem_04_04_GreenChem\" class=\"scaled-down\">\n<div class=\"bc-figcaption figcaption\">(a) Ibuprofen is a popular nonprescription pain medication commonly sold as 200 mg tablets. (b) The BHC process for synthesizing ibuprofen requires only three steps and exhibits an impressive atom economy. (credit a: modification of work by Derrick Coetzee)<\/div>\n<p><span id=\"fs-idp994368\" data-type=\"media\" data-alt=\"This figure is labeled, \u201ca,\u201d and, \u201cb.\u201d Part a shows an open bottle of ibuprofen and a small pile of ibuprofen tablets beside it. Part b shows a reaction along with line structures. The first line structure looks like a diagonal line pointing down and to the right, then up and to the right and then down and to the right. At this point it connects to a hexagon with alternating double bonds. At the first trough there is a line that points straight down. From this structure, there is an arrow pointing downward. The arrow is labeled, \u201cH F,\u201d on the left and \u201c( C H subscript 3 C O ) subscript 2 O,\u201d on the right. The next line structure looks exactly like the first line structure, but it has a line angled down and to the right from the lower right point of the hexagon. This line is connected to another line which points straight down. Where these two lines meet, there is a double bond to an O atom. There is another arrow pointing downward, and it is labeled, \u201cH subscript 2, Raney N i.\u201d The next structure looks very similar to the second, previous structure, except in place of the double bonded O, there is a singly bonded O H group. There is a final reaction arrow pointing downward, and it is labeled, \u201cC O, [ P d ].\u201d The final structure is similar to the third, previous structure except in place of the O H group, there is another line that points down and to the right to an O H group. At these two lines, there is a double bonded O.\"><img decoding=\"async\" src=\"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-content\/uploads\/sites\/1463\/2021\/07\/CNX_Chem_04_04_GreenChem-1.jpg\" alt=\"This figure is labeled, \u201ca,\u201d and, \u201cb.\u201d Part a shows an open bottle of ibuprofen and a small pile of ibuprofen tablets beside it. Part b shows a reaction along with line structures. The first line structure looks like a diagonal line pointing down and to the right, then up and to the right and then down and to the right. At this point it connects to a hexagon with alternating double bonds. At the first trough there is a line that points straight down. From this structure, there is an arrow pointing downward. The arrow is labeled, \u201cH F,\u201d on the left and \u201c( C H subscript 3 C O ) subscript 2 O,\u201d on the right. The next line structure looks exactly like the first line structure, but it has a line angled down and to the right from the lower right point of the hexagon. This line is connected to another line which points straight down. Where these two lines meet, there is a double bond to an O atom. There is another arrow pointing downward, and it is labeled, \u201cH subscript 2, Raney N i.\u201d The next structure looks very similar to the second, previous structure, except in place of the double bonded O, there is a singly bonded O H group. There is a final reaction arrow pointing downward, and it is labeled, \u201cC O, [ P d ].\u201d The final structure is similar to the third, previous structure except in place of the O H group, there is another line that points down and to the right to an O H group. At these two lines, there is a double bonded O.\" data-media-type=\"image\/jpeg\" \/><\/span><\/p>\n<\/div>\n<\/div>\n<\/div>\n<div id=\"fs-idm64875168\" class=\"summary\" data-depth=\"1\">\n<h3 data-type=\"title\"><strong>Key Concepts and Summary<\/strong><\/h3>\n<p id=\"fs-idm5314032\">When reactions are carried out using less-than-stoichiometric quantities of reactants, the amount of product generated will be determined by the limiting reactant. The amount of product generated by a chemical reaction is its actual yield. This yield is often less than the amount of product predicted by the stoichiometry of the balanced chemical equation representing the reaction (its theoretical yield). The extent to which a reaction generates the theoretical amount of product is expressed as its percent yield.<\/p>\n<\/div>\n<div id=\"fs-idm49138160\" class=\"exercises\" data-depth=\"1\">\n<div id=\"fs-idm19471568\" data-type=\"exercise\">\n<div id=\"fs-idp17552400\" data-type=\"solution\">\n<p id=\"fs-idp8960064\">\n<\/div>\n<\/div>\n<\/div>\n<div class=\"textbox shaded\" data-type=\"glossary\">\n<h3 data-type=\"glossary-title\"><strong>Glossary<\/strong><\/h3>\n<dl id=\"fs-idm47393392\">\n<dt>actual yield<\/dt>\n<dd id=\"fs-idp169189008\">amount of product formed in a reaction<\/dd>\n<\/dl>\n<dl id=\"fs-idm46343008\">\n<dt>excess reactant<\/dt>\n<dd id=\"fs-idp169769328\">reactant present in an amount greater than required by the reaction stoichiometry<\/dd>\n<\/dl>\n<dl id=\"fs-idp182610272\">\n<dt>limiting reactant<\/dt>\n<dd id=\"fs-idp67500512\">reactant present in an amount lower than required by the reaction stoichiometry, thus limiting the amount of product generated<\/dd>\n<\/dl>\n<dl id=\"fs-idp51447712\">\n<dt>percent yield<\/dt>\n<dd id=\"fs-idp172539984\">measure of the efficiency of a reaction, expressed as a percentage of the theoretical yield<\/dd>\n<\/dl>\n<dl id=\"fs-idp30967968\">\n<dt>theoretical yield<\/dt>\n<dd id=\"fs-idm94035648\">amount of product that may be produced from a given amount of reactant(s) according to the reaction stoichiometry<\/dd>\n<\/dl>\n<\/div>\n","protected":false},"author":1392,"menu_order":5,"template":"","meta":{"pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[48],"contributor":[],"license":[],"class_list":["post-205","chapter","type-chapter","status-publish","hentry","chapter-type-numberless"],"part":177,"_links":{"self":[{"href":"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-json\/pressbooks\/v2\/chapters\/205","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-json\/wp\/v2\/users\/1392"}],"version-history":[{"count":6,"href":"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-json\/pressbooks\/v2\/chapters\/205\/revisions"}],"predecessor-version":[{"id":2119,"href":"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-json\/pressbooks\/v2\/chapters\/205\/revisions\/2119"}],"part":[{"href":"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-json\/pressbooks\/v2\/parts\/177"}],"metadata":[{"href":"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-json\/pressbooks\/v2\/chapters\/205\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-json\/wp\/v2\/media?parent=205"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-json\/pressbooks\/v2\/chapter-type?post=205"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-json\/wp\/v2\/contributor?post=205"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/aperrott\/wp-json\/wp\/v2\/license?post=205"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}