{"id":3223,"date":"2016-08-25T19:32:16","date_gmt":"2016-08-25T19:32:16","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/?post_type=chapter&#038;p=3223"},"modified":"2016-08-26T19:19:02","modified_gmt":"2016-08-26T19:19:02","slug":"catalysts","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/chapter\/catalysts\/","title":{"raw":"Catalysts","rendered":"Catalysts"},"content":{"raw":"<div class=\"textbox learning-objectives\">\r\n<h3>Learning Objectives<\/h3>\r\n<div>\r\n<ul>\r\n \t<li>Define catalyst.<\/li>\r\n \t<li>Explain how catalysts influence the rate of a chemical reaction.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<\/div>\r\n<div class=\"textbox examples\">\r\n<h3>Where did the sun go?<\/h3>\r\n[caption id=\"\" align=\"aligncenter\" width=\"400\"]<img src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/53\/2014\/08\/19212838\/20140811155714764049.jpeg\" alt=\"A catalytic converter reduces the amount of toxic products created from incomplete combustion\" width=\"400\" height=\"325\" \/> Smog in New York City. Courtesy of Dr. Edwin P. Ewing, Jr., CDC\/<a href=\"https:\/\/commons.wikimedia.org\/wiki\/File:SmogNY.jpg\">Wikimedia<\/a>.[\/caption]\r\n\r\nGasoline-powered vehicles emit a lot of harmful materials. Nitrogen oxides are formed when atmospheric nitrogen reacts with oxygen at the high temperatures found in a car engine. Carbon monoxide is a by-product of incomplete combustion of hydrocarbons. Evaporated and unused fuel releases volatile hydrocarbons into the atmosphere to help form smog. The presence of a catalytic converter in the exhaust system of the car causes these materials to react and be changed into less harmful products.\r\n\r\n<\/div>\r\n<h2>Catalysts<\/h2>\r\nSometimes a substance can be added to a chemical reaction and it will cause that reaction to undergo a dramatic increase in rate. Hydrogen peroxide is used as a disinfectant for scrapes and cuts and is found in many medicine cabinets as a 3% aqueous solution. Hydrogen peroxide naturally decomposes to produce water and oxygen gas, but the reaction is very slow. A bottle of hydrogen peroxide will last for several years before it needs to be replaced. However, the addition of just a small amount of manganese(IV) oxide to hydrogen peroxide will cause it to decompose completely in just a matter of minutes. A <strong> catalyst <\/strong> is a substance that increases the rate of a chemical reaction by lowering the activation energy without being used up in the reaction. After the reaction occurs, a catalyst returns to its original state and so catalysts can be used over and over again. Because it is neither a reactant nor a product, a catalyst is shown in a chemical equation by being written above the yield arrow.\r\n\r\n<img class=\"aligncenter\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/53\/2014\/08\/19212839\/74fb4180834da6f75379f53cadc3011f.png\" alt=\"2text{H}_2 text{O}_2(aq) overset{text{MnO}_2}{longrightarrow} 2text{H}_2text{O}(l)+text{O}_2(g)\" width=\"257\" height=\"24\" \/>\r\n\r\nA catalyst works by changing the specific way in which the reaction occurs, called its mechanism. The important outcome from the use of a catalyst is that the overall activation energy of the reaction is lowered (see <strong> Figure <\/strong><a href=\"#x-ck12-OTgwNDUtMTM2NDYyMzgyNi0zMi01Ny01LjcuMQ..\"> below <\/a> ). With a lower activation energy barrier, a greater percentage of reactant molecules are able to have effective collisions and the reaction rate increases.\r\n<div>\r\n\r\n[caption id=\"\" align=\"aligncenter\" width=\"512\"]<img src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/53\/2014\/08\/19212840\/20140811155714879494.png\" alt=\"The addition of a catalyst lowers activation energy, which increases the rate of a reaction\" width=\"512\" height=\"187\" longdesc=\"The%20addition%20of%20a%20catalyst%20to%20a%20reaction%20lowers%20the%20activation%20energy%2C%20increasing%20the%20rate%20of%20the%20reaction.%20The%20activation%20energy%20of%20the%20uncatalyzed%20reaction%20is%20shown%20by%20Ea%2C%20while%20the%20catalyzed%20reaction%20is%20shown%20by%20Ea%E2%80%99.%20The%20heat%20of%20reaction%20(%CE%94H)%20is%20unchanged%20by%20the%20presence%20of%20the%20catalyst.\" \/> Figure 1. The addition of a catalyst to a reaction lowers the activation energy, increasing the rate of the reaction. The activation energy of the uncatalyzed reaction is shown by Ea, while the catalyzed reaction is shown by Ea\u2019. The heat of reaction (\u0394H) is unchanged by the presence of the catalyst. Image from the CK-12 Foundation - Christopher Auyeung.[\/caption]\r\n\r\n&nbsp;\r\n\r\n<\/div>\r\nCatalysts are extremely important parts of many chemical reactions. Enzymes in your body act as nature\u2019s catalysts, allowing important biochemical reactions to occur at reasonable rates. Chemical companies constantly search for new and better catalysts to make reactions go faster and thus make the company more profitable.\r\n<div class=\"textbox key-takeaways\">\r\n<h3>Summary<\/h3>\r\n<ul>\r\n \t<li>The function of a catalyst is described.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<div class=\"textbox exercises\">\r\n<h3>Practice<\/h3>\r\nWatch the video at the link below and answer the following questions:\r\n\r\n<a href=\"http:\/\/www.youtube.com\/watch?v=9KQdF1bnXHE\"> http:\/\/www.youtube.com\/watch?v=9KQdF1bnXHE <\/a>\r\n<ol>\r\n \t<li>What dye is used on blue jeans?<\/li>\r\n \t<li>What do enzymes do for the blue jeans?<\/li>\r\n \t<li>List three issues that exist for uncatalyzed reactions.<\/li>\r\n<\/ol>\r\n<\/div>\r\n<div class=\"textbox exercises\">\r\n<h3>Review<\/h3>\r\n<ol>\r\n \t<li>What does a catalyst affect in a chemical reaction?<\/li>\r\n \t<li>Is the <img src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/53\/2014\/08\/19212619\/58e2d6b1f6cbdc5e4c424671b4016000.png\" alt=\"Delta H\" width=\"31\" height=\"12\" \/> for the process affected?<\/li>\r\n \t<li>When writing a chemical equation, where do we indicate the catalyst?<\/li>\r\n<\/ol>\r\n<\/div>\r\n<h2>Glossary<\/h2>\r\n<div>\r\n<ul>\r\n \t<li><strong> catalyst: <\/strong> A substance that increases the rate of a chemical reaction by lowering the activation energy without being used up in the reaction.<\/li>\r\n<\/ul>\r\n<\/div>","rendered":"<div class=\"textbox learning-objectives\">\n<h3>Learning Objectives<\/h3>\n<div>\n<ul>\n<li>Define catalyst.<\/li>\n<li>Explain how catalysts influence the rate of a chemical reaction.<\/li>\n<\/ul>\n<\/div>\n<\/div>\n<div class=\"textbox examples\">\n<h3>Where did the sun go?<\/h3>\n<div style=\"width: 410px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/53\/2014\/08\/19212838\/20140811155714764049.jpeg\" alt=\"A catalytic converter reduces the amount of toxic products created from incomplete combustion\" width=\"400\" height=\"325\" \/><\/p>\n<p class=\"wp-caption-text\">Smog in New York City. Courtesy of Dr. Edwin P. Ewing, Jr., CDC\/<a href=\"https:\/\/commons.wikimedia.org\/wiki\/File:SmogNY.jpg\">Wikimedia<\/a>.<\/p>\n<\/div>\n<p>Gasoline-powered vehicles emit a lot of harmful materials. Nitrogen oxides are formed when atmospheric nitrogen reacts with oxygen at the high temperatures found in a car engine. Carbon monoxide is a by-product of incomplete combustion of hydrocarbons. Evaporated and unused fuel releases volatile hydrocarbons into the atmosphere to help form smog. The presence of a catalytic converter in the exhaust system of the car causes these materials to react and be changed into less harmful products.<\/p>\n<\/div>\n<h2>Catalysts<\/h2>\n<p>Sometimes a substance can be added to a chemical reaction and it will cause that reaction to undergo a dramatic increase in rate. Hydrogen peroxide is used as a disinfectant for scrapes and cuts and is found in many medicine cabinets as a 3% aqueous solution. Hydrogen peroxide naturally decomposes to produce water and oxygen gas, but the reaction is very slow. A bottle of hydrogen peroxide will last for several years before it needs to be replaced. However, the addition of just a small amount of manganese(IV) oxide to hydrogen peroxide will cause it to decompose completely in just a matter of minutes. A <strong> catalyst <\/strong> is a substance that increases the rate of a chemical reaction by lowering the activation energy without being used up in the reaction. After the reaction occurs, a catalyst returns to its original state and so catalysts can be used over and over again. Because it is neither a reactant nor a product, a catalyst is shown in a chemical equation by being written above the yield arrow.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/53\/2014\/08\/19212839\/74fb4180834da6f75379f53cadc3011f.png\" alt=\"2text{H}_2 text{O}_2(aq) overset{text{MnO}_2}{longrightarrow} 2text{H}_2text{O}(l)+text{O}_2(g)\" width=\"257\" height=\"24\" \/><\/p>\n<p>A catalyst works by changing the specific way in which the reaction occurs, called its mechanism. The important outcome from the use of a catalyst is that the overall activation energy of the reaction is lowered (see <strong> Figure <\/strong><a href=\"#x-ck12-OTgwNDUtMTM2NDYyMzgyNi0zMi01Ny01LjcuMQ..\"> below <\/a> ). With a lower activation energy barrier, a greater percentage of reactant molecules are able to have effective collisions and the reaction rate increases.<\/p>\n<div>\n<div style=\"width: 522px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/53\/2014\/08\/19212840\/20140811155714879494.png\" alt=\"The addition of a catalyst lowers activation energy, which increases the rate of a reaction\" width=\"512\" height=\"187\" longdesc=\"The%20addition%20of%20a%20catalyst%20to%20a%20reaction%20lowers%20the%20activation%20energy%2C%20increasing%20the%20rate%20of%20the%20reaction.%20The%20activation%20energy%20of%20the%20uncatalyzed%20reaction%20is%20shown%20by%20Ea%2C%20while%20the%20catalyzed%20reaction%20is%20shown%20by%20Ea%E2%80%99.%20The%20heat%20of%20reaction%20(%CE%94H)%20is%20unchanged%20by%20the%20presence%20of%20the%20catalyst.\" \/><\/p>\n<p class=\"wp-caption-text\">Figure 1. The addition of a catalyst to a reaction lowers the activation energy, increasing the rate of the reaction. The activation energy of the uncatalyzed reaction is shown by Ea, while the catalyzed reaction is shown by Ea\u2019. The heat of reaction (\u0394H) is unchanged by the presence of the catalyst. Image from the CK-12 Foundation &#8211; Christopher Auyeung.<\/p>\n<\/div>\n<p>&nbsp;<\/p>\n<\/div>\n<p>Catalysts are extremely important parts of many chemical reactions. Enzymes in your body act as nature\u2019s catalysts, allowing important biochemical reactions to occur at reasonable rates. Chemical companies constantly search for new and better catalysts to make reactions go faster and thus make the company more profitable.<\/p>\n<div class=\"textbox key-takeaways\">\n<h3>Summary<\/h3>\n<ul>\n<li>The function of a catalyst is described.<\/li>\n<\/ul>\n<\/div>\n<div class=\"textbox exercises\">\n<h3>Practice<\/h3>\n<p>Watch the video at the link below and answer the following questions:<\/p>\n<p><a href=\"http:\/\/www.youtube.com\/watch?v=9KQdF1bnXHE\"> http:\/\/www.youtube.com\/watch?v=9KQdF1bnXHE <\/a><\/p>\n<ol>\n<li>What dye is used on blue jeans?<\/li>\n<li>What do enzymes do for the blue jeans?<\/li>\n<li>List three issues that exist for uncatalyzed reactions.<\/li>\n<\/ol>\n<\/div>\n<div class=\"textbox exercises\">\n<h3>Review<\/h3>\n<ol>\n<li>What does a catalyst affect in a chemical reaction?<\/li>\n<li>Is the <img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/53\/2014\/08\/19212619\/58e2d6b1f6cbdc5e4c424671b4016000.png\" alt=\"Delta H\" width=\"31\" height=\"12\" \/> for the process affected?<\/li>\n<li>When writing a chemical equation, where do we indicate the catalyst?<\/li>\n<\/ol>\n<\/div>\n<h2>Glossary<\/h2>\n<div>\n<ul>\n<li><strong> catalyst: <\/strong> A substance that increases the rate of a chemical reaction by lowering the activation energy without being used up in the reaction.<\/li>\n<\/ul>\n<\/div>\n\n\t\t\t <section class=\"citations-section\" role=\"contentinfo\">\n\t\t\t <h3>Candela Citations<\/h3>\n\t\t\t\t\t <div>\n\t\t\t\t\t\t <div id=\"citation-list-3223\">\n\t\t\t\t\t\t\t <div class=\"licensing\"><div class=\"license-attribution-dropdown-subheading\">CC licensed content, Shared previously<\/div><ul class=\"citation-list\"><li>Chemistry Concepts Intermediate. <strong>Authored by<\/strong>: Calbreath, Baxter, et al.. <strong>Provided by<\/strong>: CK12.org. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"http:\/\/www.ck12.org\/book\/CK-12-Chemistry-Concepts-Intermediate\/\">http:\/\/www.ck12.org\/book\/CK-12-Chemistry-Concepts-Intermediate\/<\/a>. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/\">CC BY-NC: Attribution-NonCommercial<\/a><\/em><\/li><\/ul><\/div>\n\t\t\t\t\t\t <\/div>\n\t\t\t\t\t <\/div>\n\t\t\t <\/section>","protected":false},"author":29,"menu_order":7,"template":"","meta":{"_candela_citation":"[{\"type\":\"cc\",\"description\":\"Chemistry Concepts Intermediate\",\"author\":\"Calbreath, Baxter, et al.\",\"organization\":\"CK12.org\",\"url\":\"http:\/\/www.ck12.org\/book\/CK-12-Chemistry-Concepts-Intermediate\/\",\"project\":\"\",\"license\":\"cc-by-nc\",\"license_terms\":\"\"}]","CANDELA_OUTCOMES_GUID":"","pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-3223","chapter","type-chapter","status-publish","hentry"],"part":2339,"_links":{"self":[{"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/pressbooks\/v2\/chapters\/3223","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/wp\/v2\/users\/29"}],"version-history":[{"count":4,"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/pressbooks\/v2\/chapters\/3223\/revisions"}],"predecessor-version":[{"id":3433,"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/pressbooks\/v2\/chapters\/3223\/revisions\/3433"}],"part":[{"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/pressbooks\/v2\/parts\/2339"}],"metadata":[{"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/pressbooks\/v2\/chapters\/3223\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/wp\/v2\/media?parent=3223"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/pressbooks\/v2\/chapter-type?post=3223"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/wp\/v2\/contributor?post=3223"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/wp\/v2\/license?post=3223"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}