{"id":384,"date":"2017-08-21T06:46:12","date_gmt":"2017-08-21T06:46:12","guid":{"rendered":"http:\/\/americanboard.org\/Subjects\/chemistry\/?page_id=384"},"modified":"2017-09-08T08:00:40","modified_gmt":"2017-09-08T08:00:40","slug":"types-of-chemical-equations","status":"publish","type":"page","link":"https:\/\/americanboard.org\/Subjects\/chemistry\/types-of-chemical-equations\/","title":{"rendered":"Types of Chemical Equations"},"content":{"rendered":"<div class=\"twelve columns\" style=\"margin-top: 10%;\">\n<div class=\"advance\">\n<p><a class=\"button button-primary\" href=\"http:\/\/americanboard.org\/Subjects\/chemistry\/classifying-chemical-reactions-and-predicting-products\">\u2b05 Previous\u00a0Lesson<\/a>\u00a0<a class=\"button\" href=\"http:\/\/americanboard.org\/Subjects\/chemistry\/reactions-and-reactivity\">Workshop Index<\/a>\u00a0<a class=\"button button-primary\" href=\"http:\/\/americanboard.org\/Subjects\/chemistry\/the-mole\">Next Lesson\u00a0\u27a1<\/a><\/p>\n<\/div>\n<p><!-- UPDATE NEXT\/PREVIOUS ABOVE --><\/p>\n<p><!-- CONTENT STARTS HERE --><\/p>\n<h1 id=\"title\">Types of Chemical Equations<\/h1>\n<h4>Objective<\/h4>\n<p>In this lesson we will review three ways to write equations for reactions in aqueous solutions: molecular\u00a0equations, ionic equations, and net ionic equations.<\/p>\n<h4>Previously we covered&#8230;<\/h4>\n<ul>\n<li>Chemical reactions, shown by balanced chemical\u00a0equations, can be classified into 5 basic types:\n<ul>\n<li>Combination or synthesis reactions<\/li>\n<li>Decomposition reactions<\/li>\n<li>Single replacement or single displacement reactions<\/li>\n<li>Double replacement (displacement) or metathesis reactions<\/li>\n<li>Combustion reactions<\/li>\n<\/ul>\n<\/li>\n<li>By knowing the type of chemical reactions, products\u00a0of reactions can be determined from the basic patterns for the\u00a0reactions.<\/li>\n<\/ul>\n<section>\n<h3>Types of Chemical Equations<\/h3>\n<p>When equations are written\u00a0to show all the reactants and\u00a0products, including their physical state, the equations are called <abbr title=\"A reaction written using the full formulas of reactants and products\">molecular\u00a0equations<\/abbr>; that is, they show all of the elements and\u00a0compounds that are\u00a0involved in the reaction. The reactions in the previous sections have\u00a0been\u00a0shown using molecular equations, such as:<\/p>\n<p class=\"center\">2AgNO<sub>3<\/sub>(<em>aq<\/em>) + Cu(<em>s<\/em>)\u00a0 \u2192 \u00a02Ag(<em>s<\/em>) +\u00a0Cu(NO<sub>3<\/sub>)<sub>2<\/sub>(<em>aq<\/em>)<\/p>\n<p>Because many reactions occur\u00a0in solution which is what\u00a0the aqueous (<em>aq<\/em>) symbol represents, chemists also\u00a0use two other ways to\u00a0show reactions when only specific parts of the compounds are taking\u00a0part in the\u00a0reaction.<\/p>\n<p>An <abbr title=\"A reaction written so that the ions are explicitly shown\">ionic equation<\/abbr> can\u00a0be written whenever\u00a0soluble ionic\u00a0compounds are used in a reaction. When solid AgNO<sub>3 <\/sub>is dissolved in\u00a0water, the water molecules separate the cations and anions in the\u00a0silver\u00a0nitrate. When AgNO<sub>3<\/sub>(<em>aq<\/em>) is\u00a0written, the chemist knows that\u00a0the ions have been separated and can be thought of as Ag<sup>+<\/sup>(<em>aq<\/em>)\u00a0and NO<sub>3<\/sub><sup>\u2212 <\/sup>(<em>aq<\/em>).\u00a0The solid copper is not soluble in<br \/>\nwater and does not form ions when placed in water so its representation\u00a0remains\u00a0the same. As the reaction proceeds, the copper metal forms copper(II)\u00a0ion and\u00a0the silver ion forms insoluble elemental silver. The soluble product of\u00a0the\u00a0reaction is the Cu(NO<sub>3<\/sub>)<sub>2<\/sub> which is written as Cu<sup>2+<\/sup>(<em>aq<\/em>)\u00a0and 2NO<sub>3<\/sub><sup>\u2212 <\/sup>(<em>aq<\/em>).<\/p>\n<p>Written in ionic form the reaction\u00a0looks like this:<\/p>\n<p class=\"center\">2Ag<sup>+<\/sup>(<em>aq<\/em>) +\u00a02NO<sub>3<\/sub><sup>\u2212<\/sup>(<em>aq<\/em>)\u00a0+ Cu(<em>s<\/em>) \u2192 2Ag(<em>s<\/em>) + Cu<sup>2+<\/sup>(<em>aq<\/em>)\u00a0+ 2NO<sub>3<\/sub><sup>\u2212 <\/sup>(<em>aq<\/em>)<\/p>\n<p>The\u00a0third\u00a0form of equation that can be written is the <abbr title=\"A reaction written with the spectator ions removed \">net ionic equation<\/abbr>.\u00a0Just as\u00a0the net weight on a grocery product tells the consumer the weight of\u00a0the\u00a0contents, or your net pay tells you how much money you have in your\u00a0pocket, a\u00a0net ionic equation tells the chemist exactly what ions and species\u00a0reacted,\u00a0omitting from the reaction those ions which can be found in exactly the\u00a0same\u00a0form in products and reactants. They are rather like \u201cbeaker\u00a0bums\u201d\u2014observing\u00a0the reaction, but not taking part in it. For that reason, these ions\u00a0are called <abbr title=\"An ion that appears on both sides of the reaction arrow\">spectator\u00a0ions<\/abbr>.<\/p>\n<p>Removing the spectator ions\u00a0from the previous example\u00a0shows a net ionic equation of<\/p>\n<p class=\"center\">2Ag<sup>+<\/sup>(<em>aq<\/em>)\u00a0+ Cu(<em>s<\/em>) \u2192 2Ag(<em>s<\/em>)\u00a0+ Cu<sup>2+<\/sup>(<em>aq<\/em>) .<\/p>\n<p>The nitrate\u00a0ions\u2019 only purpose was as an anion\u00a0to provide a source of silver ions.<\/p>\n<p>In double replacement reactions, if one of the products is not soluble or is a weak electrolyte that\u00a0product can not be written as aqueous ions and must be included in its molecular form in the\u00a0equation.<\/p>\n<p>If aqueous calcium chloride reacts with aqueous lead(II) acetate, solid lead(II) chloride will form,\u00a0with the calcium acetate remaining in solution. The net ionic equation for the reaction would simply be:<\/p>\n<p class=\"center\">Pb<sup>2+<\/sup>(<em>aq<\/em>) + 2Cl<sup>\u2212 <\/sup>(<em>aq<\/em>) \u2192 PbCl<sub>2<\/sub>(<em>s<\/em>)<\/p>\n<p>The calcium ions and acetate ions would remain in solution. Only upon evaporation of the water in the\u00a0solution would solid calcium acetate be found.<\/p>\n<p><!-- CONTENT ENDS HERE --><\/p>\n<p><!-- UPDATE NEXT\/PREVIOUS BELOW --><\/p>\n<div class=\"advance\"><a class=\"button button-primary\" href=\"http:\/\/americanboard.org\/Subjects\/chemistry\/classifying-chemical-reactions-and-predicting-products\">\u2b05 Previous\u00a0Lesson<\/a>\u00a0<a class=\"button\" href=\"http:\/\/americanboard.org\/Subjects\/chemistry\/reactions-and-reactivity\">Workshop Index<\/a>\u00a0<a class=\"button button-primary\" href=\"http:\/\/americanboard.org\/Subjects\/chemistry\/the-mole\">Next Lesson\u00a0\u27a1<\/a><\/div>\n<p><a class=\"backtotop\" href=\"#title\">Back to Top<\/a><\/p>\n<\/section>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>\u2b05 Previous\u00a0Lesson\u00a0Workshop Index\u00a0Next Lesson\u00a0\u27a1 Types of Chemical Equations Objective In this lesson we will review three ways to write equations for reactions in aqueous solutions: molecular\u00a0equations, ionic equations, and net ionic equations. Previously we covered&#8230; Chemical reactions, shown by balanced chemical\u00a0equations, can be classified into 5 basic types: Combination or synthesis reactions Decomposition reactions Single [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-384","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/americanboard.org\/Subjects\/chemistry\/wp-json\/wp\/v2\/pages\/384","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/americanboard.org\/Subjects\/chemistry\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/americanboard.org\/Subjects\/chemistry\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/americanboard.org\/Subjects\/chemistry\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/americanboard.org\/Subjects\/chemistry\/wp-json\/wp\/v2\/comments?post=384"}],"version-history":[{"count":6,"href":"https:\/\/americanboard.org\/Subjects\/chemistry\/wp-json\/wp\/v2\/pages\/384\/revisions"}],"predecessor-version":[{"id":674,"href":"https:\/\/americanboard.org\/Subjects\/chemistry\/wp-json\/wp\/v2\/pages\/384\/revisions\/674"}],"wp:attachment":[{"href":"https:\/\/americanboard.org\/Subjects\/chemistry\/wp-json\/wp\/v2\/media?parent=384"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}