File "the-equilibrium-law.html"
Path: /StudyIB/chemistry/page/896/the-equilibrium-lawhtml
File size: 59.53 KB
MIME-type: text/html
Charset: utf-8
<!DOCTYPE html><html lang="EN"><head> <script>(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start': new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0], j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src= 'https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f); })(window,document,'script','dataLayer','GTM-PZBWZ8J');</script> <title>The equilibrium law</title><!-- Removed by WebCopy --><!--<base href="/">--><!-- Removed by WebCopy --><meta http-equiv="x-ua-compatible" content="IE=Edge"><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1"><link href="../../../css/bootstrap.flatly.min.css" rel="stylesheet" media="screen"><link rel="stylesheet" href="../../../fonts/awesome/css/font-awesome.min.css"><link href="../../../js/jquery-fancybox/jquery.fancybox.min.css" type="text/css" rel="stylesheet"><link rel="stylesheet" href="../../../css/style.min.css?v=202301301645"><meta name="robots" content="index, follow"><meta name="googlebot" content="noarchive"><meta prefix="og: http://ogp.me/ns#" property="og:title" name="og:title" content="StudyIB Chemistry: The equilibrium law"> <meta prefix="og: http://ogp.me/ns#" property="og:image" content="https://studyib.net/img/studyib-card-default.jpg"> <meta prefix="og: http://ogp.me/ns#" property="og:description" name="og:description" content="17.1 Equilibrium calculations, like mole calculations, need lots of practice."> <meta prefix="og: http://ogp.me/ns#" property="og:url" name="og:url" content="https://studyib.net/chemistry/page/896/the-equilibrium-law"> <meta prefix="og: http://ogp.me/ns#" property="og:site_name" name="og:site_name" content="StudyIB - Your IB learning companion"> <meta prefix="og: http://ogp.me/ns#" property="og:locale" name="og:locale" content="en"> <meta prefix="og: http://ogp.me/ns#" property="og:type" name="og:type" content="website"> <meta name="description" content="17.1 Equilibrium calculations, like mole calculations, need lots of practice."> <meta name="image" content="https://studyib.net/img/studyib-card-default.jpg"> <meta name="keywords" content="IB, IBDP, InThinking, International Baccalaureate, Revision, Revision websites, Student Sites, Students, Learning, Guidance, Exam, Questions, Practice problems, Diagnose, Help, Notes"> <meta itemprop="name" content="StudyIB Chemistry: The equilibrium law"> <meta itemprop="description" content="17.1 Equilibrium calculations, like mole calculations, need lots of practice."> <meta itemprop="image" content="https://studyib.net/img/studyib-card-default.jpg"> <meta name="twitter:card" content="summary_large_image"> <meta name="twitter:title" content="StudyIB Chemistry: The equilibrium law"> <meta name="twitter:description" content="17.1 Equilibrium calculations, like mole calculations, need lots of practice."> <meta name="twitter:image" content="https://studyib.net/img/studyib-card-default.jpg"> <meta name="twitter:creator" content="@inthinker"><link rel="stylesheet" href="../../../css/snippets.min.css?v=202209111300"><link rel="stylesheet" href="../../../css/article.min.css?v=202211221000"><style type="text/css">.filter-sl-only { display: none; }</style><script src="../../../ajax/libs/mathjax/2.7.0/MathJax.js?config=TeX-AMS-MML_HTMLorMML"></script><script src="../../../js/ifvisible.min.js"></script><script>ifvisible.setIdleDuration(300);</script><link rel="apple-touch-icon-precomposed" sizes="57x57" href="../../../img/favicon/apple-touch-icon-57x57.png"> <link rel="apple-touch-icon-precomposed" sizes="114x114" href="../../../img/favicon/apple-touch-icon-114x114.png"> <link rel="apple-touch-icon-precomposed" sizes="72x72" href="../../../img/favicon/apple-touch-icon-72x72.png"> <link rel="apple-touch-icon-precomposed" sizes="144x144" href="../../../img/favicon/apple-touch-icon-144x144.png"> <link rel="apple-touch-icon-precomposed" sizes="60x60" href="../../../img/favicon/apple-touch-icon-60x60.png"> <link rel="apple-touch-icon-precomposed" sizes="120x120" href="../../../img/favicon/apple-touch-icon-120x120.png"> <link rel="apple-touch-icon-precomposed" sizes="76x76" href="../../../img/favicon/apple-touch-icon-76x76.png"> <link rel="apple-touch-icon-precomposed" sizes="152x152" href="../../../img/favicon/apple-touch-icon-152x152.png"> <link rel="icon" type="image/png" href="../../../img/favicon/favicon-196x196.png" sizes="196x196"> <link rel="icon" type="image/png" href="../../../img/favicon/favicon-96x96.png" sizes="96x96"> <link rel="icon" type="image/png" href="../../../img/favicon/favicon-32x32.png" sizes="32x32"> <link rel="icon" type="image/png" href="../../../img/favicon/favicon-16x16.png" sizes="16x16"> <link rel="icon" type="image/png" href="../../../img/favicon/favicon-128.png" sizes="128x128"> <meta name="application-name" content="StudyIB: Your IB Learning Companion"> <meta name="msapplication-TileColor" content="#A5BED5"> <meta name="msapplication-TileImage" content="/img/favicon/mstile-144x144.png"> <meta name="msapplication-square70x70logo" content="/img/favicon/mstile-70x70.png"> <meta name="msapplication-square150x150logo" content="/img/favicon/mstile-150x150.png"> <meta name="msapplication-wide310x150logo" content="/img/favicon/mstile-310x150.png"> <meta name="msapplication-square310x310logo" content="/img/favicon/mstile-310x310.png"><script>var stdHash = "6da675cbcb3d25f050b05557349abc79", stdTicket = "082b9c9c4ae3624d";</script><script src="../../../js/user/local-stats.min.js?v=202205311700"></script><link href="../../../css/subjects-frontpage.min.css?v=202302031000" rel="stylesheet"></head><body class="public chemistry"> <noscript><iframe src="https://www.googletagmanager.com/ns.html?id=GTM-PZBWZ8J" height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript> <div id="top-header"> <div class="wmap general hidden-sm hidden-xs subjects"> <div class="layout-wrapper"> <div class="container-fluid"> <a href=""> <img class="header-thinker" src="../../../img/header-thinker.svg"> </a> <h1> <a href="../../../chemistry.html"> IBDP Chemistry </a> <a href="https://inthinking.net" title="inthinking.net" class="inthinking-logo pull-right"> <img src="../../../img/header-logo.svg" style="height: 80px; width: auto;"> </a> </h1> <p class="slogan">InThinking Revision Sites for students</p> <p class="author">Website by <strong>Paul Lloyd</strong></p> <p class="updated">Updated 1 February 2023</p> </div> </div> </div> <nav id="public-topnav" class="navbar navbar-default"> <div class="container-fluid"> <div class="navbar-header"> <a class="navbar-brand hidden-md hidden-lg" href="../../../index.htm"> <img class="header-xs-thinker" src="../../../img/header-thinker.svg"> </a> <button type="button" class="collapsed navbar-toggle" data-toggle="collapse" data-target="#subject-navbar-collapse" aria-expanded="false"> <span class="sr-only">Toggle navigation</span> <i class="fa fa-fw fa-2x fa-user"></i> </button> <div class="brand hidden-lg hidden-md hidden-sm"> <a class="brand-xs" href="../../../chemistry.html"> <strong class="title" style="white-space: nowrap;font-size: 18px;">Chemistry</strong> </a> </div> </div> <div class="collapse navbar-collapse" id="subject-navbar-collapse"> <ul class="nav navbar-bar navbar-userbox hidden-md hidden-lg"><li class="dropdown"><a href="#" class="dropdown-toggle" data-toggle="dropdown"><i class="fa fa-fw fa-lg fa-user-circle" style="margin-right: 5px;"></i><span style="font-size: 16px;"></span></a><ul class="dropdown-menu"><li class="dropdown-submenu"><a class="dropdown-toggle" href="#" data-toggle="dropdown"><i class="fa fa-fw fa-globe"></i> Subjects</a><ul class="dropdown-menu"><li></li><li class=""><a href="../../../biology.html">DP Biology</a></li><li class="active"><a href="../../../chemistry.html"><i class="fa fa-caret-right"></i> DP Chemistry</a></li><li class=""><a href="../../../englishalanglit.html">DP English A: Language & Literature</a></li><li class=""><a href="../../../mathsanalysis.html">DP Maths: Analysis & Approaches</a></li><li class=""><a href="../../../mathsapplications.html">DP Maths: Applications & Interpretations SL</a></li><li class=""><a href="../../../physics.html">DP Physics</a></li><li class=""><a href="../../../spanishb.html">DP Spanish B</a></li></ul></li><li class="menu-item"><a href="../../../user.html"><i class="fa fa-fw fa-dashboard"></i> Dashboard</a></li><li class="menu-item"><a href="../../../user/profile.html"><i class="fa fa-fw fa-cog"></i> My profile</a></li><li class="menu-item"><a href="../../../user/messages.html"><i class="fa fa-fw fa-envelope"></i> Messages</a></li><li class="menu-item hidden-md hidden-lg mt-xs-3"><a href="../../../index.htm?logout=1" class="btn btn-primary btn-xs-block"><i class="fa fa-fw fa-lg fa-power-off text-danger"></i>Log out</a></li></ul></li></ul> <ul class="nav navbar-bar"><li class=""><a class="home" href="../../../chemistry.html"><i class="fa fa-fw fa-home"></i> Home</a></li><li class=""><a class="topics" href="#"><i class="fa fa-fw fa-th-large"></i> Topics</a></li><li class=""><a class="favorites" href="../../../chemistry.html"><i class="fa fa-fw fa-star"></i> My favorites</a></li><li class=""><a class="" href="../../flashcards.html"><i class="fa fa-fw fa-bolt"></i> Flashcards</a></li><li class=""><a class="qbank" href="../../test-your-knowledge.html"><i class="fa fa-fw fa-question"></i> Question bank</a></li><li class=""><a class="networks" href="../../networks.html"><i class="fa fa-fw fa-graduation-cap"></i> Virtual tutor</a></li><li class=""><a class="" href="../../blogs.html"><i class="fa fa-fw fa-paperclip"></i> Blog</a></li><li class=""><a class="sitemap" href="../../sitemap.html"><i class="fa fa-fw fa-sitemap"></i> Sitemap</a></li><li class=""><a class="activity" href="../../../chemistry.html"><i class="fa fa-fw fa-calendar-check-o"></i> My activity</a></li></ul> <ul class="nav navbar-bar navbar-right"> <li> <form class="navbar-form hidden-md hidden-lg" role="search" method="get" action="chemistry/search"> <div class="input-group"> <input class="form-control nav-search" name="glob" type="search" placeholder="Search..."> <span class="input-group-btn"> <button type="submit" class="btn bg-blue"> <i class="fa fa-search"> </i> </button> </span> </div> </form> <a href="#" class="toggle-menu-search hidden-sm hidden-xs" data-toggle="dropdown"> <i class="fa fa-lg fa-search"></i> </a> </li></ul> </div> </div></nav><nav id="nav-menu-search" class="shadow-bottom hidden-sm hidden-xs" style="display: none;"> <div class="container-fluid"> <form class="" role="search" method="get" action="chemistry/search"> <input class="form-control nav-search" name="glob" type="search" placeholder="Search Chemistry..."> <button class="btn btn-sm btn-primary" type="submit"> Search </button> </form> </div></nav><div class="modal fade" tabindex="-1" role="dialog" id="modal-mini-login"> <div class="modal-dialog" role="document"> <div class="modal-content"> <div class="modal-body"> <button aria-hidden="true" data-dismiss="modal" class="close hidden-xs login-button-close" type="button">×</button> <form method="post"> <div class="form-group"> <input name="user-email" class="form-control" type="text" placeholder="Email"> </div> <div class="form-group"> <input name="user-password" class="form-control" type="password" placeholder="Password"> <input name="user-fp" class="fp" value="d8c893da5db7501669ffeeac46273ba6" type="hidden"> </div> <div class="form-group"> <a href="../../../reset-password.html" class="reset-password" style="font-weight: normal;"> Forgot your password? </a> </div> <div class="form-group"> <button type="submit" name="submit-login" value="1" class="btn btn-primary btn-block text-center"> <i class="fa fa-user fa-fw"></i> Log in </button> </div> </form> </div> </div> </div></div></div><div class="modal fade" id="show-topics" tabindex="-1" role="dialog"><div id="dialog-topics" class="modal-dialog modal-dialog-topics"><div class="modal-content"><div class="modal-body modal-body-topics"><div id="new-frontpage-toplevels-topics" class="frontpage-box"><div class="row"><div class="col-md-4 col-sm-4"><div class="item"><a href="../3004/free-access-weekend.html"><div class="header" style="height: 35px;"><h3 class="title special" style="margin-top: 0;">Free Access Weekend!</h3></div><div class="body"><div class="cropper" style="background-image: url('../../images/general-images/free.jpg'); height: 10vw;"></div></div></a></div></div><div class="col-md-4 col-sm-4"><div class="item"><a href="../2075/paper-1-exam-questions.html"><div class="header" style="height: 35px;"><h3 class="title special" style="margin-top: 0;">Paper 1 Exam Questions</h3></div><div class="body"><div class="cropper" style="background-image: url('../../images/test-images/exams.jpg'); height: 10vw;"></div></div></a></div></div><div class="col-md-4 col-sm-4"><div class="item"><a href="../2124/paper-2-exam-questions.html"><div class="header" style="height: 35px;"><h3 class="title special" style="margin-top: 0;">Paper 2 Exam Questions</h3></div><div class="body"><div class="cropper" style="background-image: url('../../images/general-images/paper-2.2.png'); height: 10vw;"></div></div></a></div></div><div class="col-md-4 col-sm-4"><div class="item"><a href="../1138/start-here.html"><div class="header" style="height: 35px;"><h3 class="title special" style="margin-top: 0;">Start Here</h3></div><div class="body"><div class="cropper" style="background-image: url('../../images/general-images/start-here.jpg'); height: 10vw;"></div></div></a></div></div><div class="col-md-4 col-sm-4"><div class="item"><a href="../343/stoichiometry.html"><div class="header" style="height: 35px;"><h3 class="title special" style="margin-top: 0;">Stoichiometry</h3></div><div class="body"><div class="cropper" style="background-image: url('../../images/stoichiometry/scales-1333455_640.jpg'); height: 10vw;"></div></div></a></div></div><div class="col-md-4 col-sm-4"><div class="item"><a href="../355/atomic-structure.html"><div class="header" style="height: 35px;"><h3 class="title special" style="margin-top: 0;">Atomic Structure</h3></div><div class="body"><div class="cropper" style="background-image: url('../../images/atomic-structure/the-atom.png'); height: 10vw;"></div></div></a></div></div><div class="col-md-4 col-sm-4"><div class="item"><a href="../356/periodicity.html"><div class="header" style="height: 35px;"><h3 class="title special" style="margin-top: 0;">Periodicity</h3></div><div class="body"><div class="cropper" style="background-image: url('/media/chemistry/images/periodicity/p-block.png'); height: 10vw;"></div></div></a></div></div><div class="col-md-4 col-sm-4"><div class="item"><a href="../357/bonding-and-structure.html"><div class="header" style="height: 35px;"><h3 class="title special" style="margin-top: 0;">Bonding & Structure</h3></div><div class="body"><div class="cropper" style="background-image: url('/media/chemistry/images/chemical-bonding-and-structure/crystallize-482971_640.jpg'); height: 10vw;"></div></div></a></div></div><div class="col-md-4 col-sm-4"><div class="item"><a href="../358/energetics.html"><div class="header" style="height: 35px;"><h3 class="title special" style="margin-top: 0;">Energetics</h3></div><div class="body"><div class="cropper" style="background-image: url('/media/chemistry/images/energetics-thermochemistry/fire-1030751_640.jpg'); height: 10vw;"></div></div></a></div></div><div class="col-md-4 col-sm-4"><div class="item"><a href="../359/kinetics.html"><div class="header" style="height: 35px;"><h3 class="title special" style="margin-top: 0;">Kinetics</h3></div><div class="body"><div class="cropper" style="background-image: url('/media/chemistry/images/chemical-kinetics/time-731110_640.jpg'); height: 10vw;"></div></div></a></div></div><div class="col-md-4 col-sm-4"><div class="item"><a href="../360/equilibrium.html"><div class="header" style="height: 35px;"><h3 class="title special" style="margin-top: 0;">Equilibrium</h3></div><div class="body"><div class="cropper" style="background-image: url('/media/chemistry/images/equilibrium/soda-466542_640.jpg'); height: 10vw;"></div></div></a></div></div><div class="col-md-4 col-sm-4"><div class="item"><a href="../361/acids-and-bases.html"><div class="header" style="height: 35px;"><h3 class="title special" style="margin-top: 0;">Acids & Bases</h3></div><div class="body"><div class="cropper" style="background-image: url('../../images/acids-and-bases/ui-paper-2.png'); height: 10vw;"></div></div></a></div></div><div class="col-md-4 col-sm-4"><div class="item"><a href="../362/redox-processes.html"><div class="header" style="height: 35px;"><h3 class="title special" style="margin-top: 0;">Redox Processes</h3></div><div class="body"><div class="cropper" style="background-image: url('/media/chemistry/images/redox-processes/oxide-1241222_640.jpg'); height: 10vw;"></div></div></a></div></div><div class="col-md-4 col-sm-4"><div class="item"><a href="../342/organic-chemistry.html"><div class="header" style="height: 35px;"><h3 class="title special" style="margin-top: 0;">Organic Chemistry</h3></div><div class="body"><div class="cropper" style="background-image: url('../../images/organic-chemistry/d-idose_molekulbaukasten_9173.jpg'); height: 10vw;"></div></div></a></div></div><div class="col-md-4 col-sm-4"><div class="item"><a href="../363/measurement.html"><div class="header" style="height: 35px;"><h3 class="title special" style="margin-top: 0;">Measurement</h3></div><div class="body"><div class="cropper" style="background-image: url('/media/chemistry/images/measurement-and-data/tablet-600649_640.jpg'); height: 10vw;"></div></div></a></div></div></div></div></div></div></div></div><div class="container-fluid shadow-ith"><div class="row frontpage"> <div class="col-md-3" id="left-column"> <p class="visible-xs-block"></p><div class="dropdown user-menu hidden-xs" style="margin-bottom: 20px;"> <button type="button" class="btn btn-default dropdown-toggle" data-toggle="dropdown" style="border-radius: 0; padding: 6px 18px;"> <i class="fa fa-fw fa-user-circle"></i> <small><i class="fa fa-caret-down"></i></small> </button> <ul class="dropdown-menu"> <li class="dropdown-submenu"><a href="#"><i class="fa fa-fw fa-globe"></i> Subjects</a><ul id="user-subjects-menu" class="dropdown-menu"><li></li><li class=""><a href="../../../biology.html">DP Biology</a></li><li class="active"><a href="../../../chemistry.html"><i class="fa fa-caret-right"></i> DP Chemistry</a></li><li class=""><a href="../../../englishalanglit.html">DP English A: Language & Literature</a></li><li class=""><a href="../../../mathsanalysis.html">DP Maths: Analysis & Approaches</a></li><li class=""><a href="../../../mathsapplications.html">DP Maths: Applications & Interpretations SL</a></li><li class=""><a href="../../../physics.html">DP Physics</a></li><li class=""><a href="../../../spanishb.html">DP Spanish B</a></li></ul></li><li class="divider"></li><li><a href="../../../user.html"><i class="fa fa-fw fa-dashboard"></i> Dashboard</a></li><li><a href="../../../user/profile.html"><i class="fa fa-fw fa-cog"></i> My profile</a></li><li><a href="../../../user/messages.html"><i class="fa fa-fw fa-envelope"></i> Messages</a></li> <li class="divider"></li> <li> <a href="../../../index.htm?logout=1"> <i class="fa fa-fw fa-power-off"></i> Log out </a> </li> </ul></div> <div id="side-nav"><h4 class="side-nav-title dropdown"><a href="../360/equilibrium.html" class="dropdown-toggle toplevel-dropdown" data-toggle="dropdown"><i class="fa fa-ellipsis-v"></i></a> <a href="../360/equilibrium.html">Equilibrium</a><ul class="dropdown-menu"><li><a href="../../../chemistry.html" style="padding-left: 5px; border-bottom: solid 1px #ddd"><i class="fa fa-fw fa-home"></i> Home</a></li><li><a href="../3004/free-access-weekend.html"><i class="fa fa-fw fa-caret-right"></i> Free Access Weekend!</a></li><li><a href="../2075/paper-1-exam-questions.html"><i class="fa fa-fw fa-caret-right"></i> Paper 1 Exam Questions</a></li><li><a href="../2124/paper-2-exam-questions.html"><i class="fa fa-fw fa-caret-right"></i> Paper 2 Exam Questions</a></li><li><a href="../1138/start-here.html"><i class="fa fa-fw fa-caret-right"></i> Start Here</a></li><li><a href="../343/stoichiometry.html"><i class="fa fa-fw fa-caret-right"></i> Stoichiometry</a></li><li><a href="../355/atomic-structure.html"><i class="fa fa-fw fa-caret-right"></i> Atomic Structure</a></li><li><a href="../356/periodicity.html"><i class="fa fa-fw fa-caret-right"></i> Periodicity</a></li><li><a href="../357/bonding-and-structure.html"><i class="fa fa-fw fa-caret-right"></i> Bonding and Structure</a></li><li><a href="../358/energetics.html"><i class="fa fa-fw fa-caret-right"></i> Energetics</a></li><li><a href="../359/kinetics.html"><i class="fa fa-fw fa-caret-right"></i> Kinetics</a></li><li><a href="../361/acids-and-bases.html"><i class="fa fa-fw fa-caret-right"></i> Acids and Bases</a></li><li><a href="../362/redox-processes.html"><i class="fa fa-fw fa-caret-right"></i> Redox Processes</a></li><li><a href="../342/organic-chemistry.html"><i class="fa fa-fw fa-caret-right"></i> Organic Chemistry</a></li><li><a href="../363/measurement.html"><i class="fa fa-fw fa-caret-right"></i> Measurement</a></li></ul><div class="pull-right"><a class="sidenav-expand" title="Expand all" href="#"><i class="fa fa-plus-circle"></i></a> <a class="sidenav-compress" title="Compress all" href="#"><i class="fa fa-minus-circle"></i></a></div></h4><ul class="side-nav level-0"><li class=""><label style="padding-left: 0px"><i class="fa fa-fw"></i><a href="../895/equilibrium.html">Equilibrium</a></label></li><li class="expanded parent selected"><label style="padding-left: 0px"><i class="fa fa-fw"></i><a href="the-equilibrium-law.html">The equilibrium law</a></label></li></ul></div> <button id="show-periodic-table" class="btn btn-default btn-block" style="margin-bottom: 10px"><i class="fa fa-table"></i> Periodic table</button> <div class="hidden-xs hidden-sm"> <button class="btn btn-default btn-block text-xs-center" data-toggle="modal" data-target="#modal-feedback" style="margin-bottom: 10px"><i class="fa fa-send"></i> Feedback</button> </div> </div> <div class="col-md-9" id="main-column"> <h1 class="page_title"> The equilibrium law <a href="#" class="mark-page-favorite pull-right" data-pid="896" title="Mark as favorite" onclick="return false;"><i class="fa fa-star-o"></i></a> </h1> <ol class="breadcrumb"> <li><a href="../../../chemistry.html"><i class="fa fa-home"></i></a><i class="fa fa-fw fa-chevron-right divider"></i></li><li><a href="../360/equilibrium.html">Equilibrium</a><i class="fa fa-fw fa-chevron-right divider"></i></li><li><span class="gray">The equilibrium law</span></li> <span class="pull-right" style="color: #555" title="Suggested study time: 60 minutes"><i class="fa fa-clock-o"></i> 60'</span> </ol> <article id="main-article"> <p><img alt="" src="../../images/equilibrium/picture-1.jpg" style="width: 160px; height: 212px; float: left;">The application of numbers to equilibrium can be challenging, but if you are confident with mole calculations <em>(Stoichiometric relationships</em>), and you also have a sound understanding of how an equilibrium functions (<em>Equilibrium</em>) then it will feel a lot easier. It is worth getting plenty of practice applying the ICE (initial, change, equilibrium) method with the questions in the quiz below and in the Qbank.</p> <hr class="hidden-separator"> <div class="panel panel-has-colored-body panel-turquoise"> <div class="panel-heading"><a class="expander" href="#"><span class="fa fa-plus"></span></a> <div> <p>Key concepts</p> </div> </div> <div class="panel-body"> <div> <div class="panel-body"> <div>There are no additional key terms required. Ensure that you are confident using the terms from the other equilibrium topic (Equilibrium 7.1) and familiar with the ΔG=−RTln<em>K</em> equation. <div class="panel panel-has-colored-body panel-has-border panel-turquoise"> <div class="panel-heading"><a class="expander" href="#"><span class="fa fa-plus"></span></a> <div> <p>Equilibrium calculations</p> </div> </div> <div class="panel-body"> <div class="video-embed vimeo"><iframe allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen="" mozallowfullscreen="" webkitallowfullscreen="" height="420" width="100%" src="https://player.vimeo.com/video/386046930"></iframe></div> </div> <div class="panel-footer"> <div> </div> </div> </div> </div> </div> </div> </div> <div class="panel-footer"> <div> </div> </div> </div> <div class="panel panel-yellow panel-has-colored-body"> <div class="panel-heading"><a class="expander" href="#"><span class="fa fa-plus"></span></a> <div> <p>Essentials</p> </div> </div> <div class="panel-body"> <div> <p> The revision cards contain all of the essential content:</p> <div id="carousel-114" class="dynamic-gallery carousel slide" data-id="114"><div class="carousel-inner" role="listbox"><div class="item active"><a class="fancy" href="../../../std-galleries/7-114/screenshot-2019-06-19-at-185257.png" data-fancybox="gallery-114" title="" data-caption=""><img alt="" src="../../../std-galleries/7-114/screenshot-2019-06-19-at-185257.png"></a></div><div class="item "><a class="fancy" href="../../../std-galleries/7-114/screenshot-2019-06-19-at-185311.png" data-fancybox="gallery-114" title="" data-caption=""><img alt="" src="../../../std-galleries/7-114/screenshot-2019-06-19-at-185311.png"></a></div><div class="item "><a class="fancy" href="../../../std-galleries/7-114/screenshot-2019-06-19-at-185328.png" data-fancybox="gallery-114" title="" data-caption=""><img alt="" src="../../../std-galleries/7-114/screenshot-2019-06-19-at-185328.png"></a></div><div class="item "><a class="fancy" href="../../../std-galleries/7-114/screenshot-2019-06-19-at-185343.png" data-fancybox="gallery-114" title="" data-caption=""><img alt="" src="../../../std-galleries/7-114/screenshot-2019-06-19-at-185343.png"></a></div><div class="item "><a class="fancy" href="../../../std-galleries/7-114/screenshot-2019-06-19-at-185353.png" data-fancybox="gallery-114" title="" data-caption=""><img alt="" src="../../../std-galleries/7-114/screenshot-2019-06-19-at-185353.png"></a></div></div><a class="left carousel-control" href="#carousel-114" role="button" data-slide="prev"><i class="fa fa-fw fa-chevron-left"></i></a><a class="right carousel-control" href="#carousel-114" role="button" data-slide="next"><i class="fa fa-fw fa-chevron-right"></i></a></div><ol class="std-carousel-indicators"><li data-index="0"><img title="Click to view" src="../../../std-galleries/7-114/screenshot-2019-06-19-at-185257-thumb128.jpg"><li><li data-index="1"><img title="Click to view" src="../../../std-galleries/7-114/screenshot-2019-06-19-at-185311-thumb128.jpg"><li><li data-index="2"><img title="Click to view" src="../../../std-galleries/7-114/screenshot-2019-06-19-at-185328-thumb128.jpg"><li><li data-index="3"><img title="Click to view" src="../../../std-galleries/7-114/screenshot-2019-06-19-at-185343-thumb128.jpg"><li><li data-index="4"><img title="Click to view" src="../../../std-galleries/7-114/screenshot-2019-06-19-at-185353-thumb128.jpg"><li></li></ol> </div> </div> <div class="panel-footer"> <div> </div> </div> </div> <div class="panel panel-has-colored-body panel-green"> <div class="panel-heading"><a class="expander" href="#"><span class="fa fa-plus"></span></a> <div> <p>Test yourself</p> </div> </div> <div class="panel-body"> <div> <div class="panel-body"> <div> <div class="tib-quiz" data-stats="7-408-896"><div class="label label-default q-number">1</div><div class="exercise shadow-bottom"><div class="q-question"><p>A gaseous sample of pure iodine monobromide (IBr) is heated and allowed to reach equilibrium at 125°C.</p><p>2IBr<sub>(g) </sub>⇌ I<sub>2(g)</sub> + Br<sub>2(g)</sub></p><p>Initially there was only 0.50 mol of iodine monobromide present.</p><p>At equilibrium 0.30 mol of iodine monobromide could be detected.</p><p>How many moles of bromine (Br<sub>2</sub>) are in the equilibrium mixture?</p></div><div class="q-answer"><p><label class="radio"> <input type="radio"> <span>0.40</span></label> </p><p><label class="radio"> <input type="radio"> <span>0.20</span></label> </p><p><label class="radio"> <input class="c" type="radio"> <span>0.10</span></label> </p><p><label class="radio"> <input type="radio"> <span>0.05</span></label> </p></div><div class="q-explanation"><p>Using the initial-change-equilibrum (ICE) moles table:</p><table border="0" cellpadding="0" cellspacing="0" style="width:100%;"><tbody><tr><td style="text-align: center;"> </td><td style="text-align: center;">2IBr<sub>(g)</sub></td><td style="text-align: center;">⇌</td><td style="text-align: center;">I<sub>2(g)</sub></td><td style="text-align: center;">+</td><td style="text-align: center;">Br<sub>2(g)</sub></td></tr><tr><td style="text-align: center;">I</td><td style="text-align: center;">0.50</td><td style="text-align: center;"> </td><td style="text-align: center;">0</td><td style="text-align: center;"> </td><td style="text-align: center;">0</td></tr><tr><td style="text-align: center;">C</td><td style="text-align: center;"><strong>1st −0.20</strong></td><td style="text-align: center;"> </td><td style="text-align: center;"><strong>2nd +0.10</strong></td><td style="text-align: center;"> </td><td style="text-align: center;"><strong>2nd +0.10</strong></td></tr><tr><td style="text-align: center;">E</td><td style="text-align: center;">0.30</td><td style="text-align: center;"> </td><td style="text-align: center;"><strong>3rd 0.10</strong></td><td style="text-align: center;"> </td><td style="text-align: center;"><strong>3rd 0.10</strong></td></tr><tr><td style="text-align: center;"> </td><td style="text-align: center;"> </td><td style="text-align: center;"> </td><td style="text-align: center;"> </td><td style="text-align: center;"> </td><td style="text-align: center;"> </td></tr></tbody></table><p>The non-bold information is given in the question.</p><p>We have initial and equilibrium moles of IBr so the<strong> 1st </strong>step is to calculate the change in IBR: <strong>−0.20</strong></p><p>If we have the change in IBr we can then calculate the change in I<sub>2</sub> and Br<sub>2 </sub>(<strong>2nd</strong>): The mole ratio is 2:1, so two moles of IBr used up will produced one mole of iodine and one mole of bromine. Thus 0.20 mol of IBr used up will produced <strong>0.10</strong> mol of both iodine and bromine.</p><p>We now have the initial moles and change for Br<sub>2</sub>, so lastly (<strong>3rd</strong>) we can calculate the moles at equilibrium: 0+0.10=<strong>0.10</strong> mol</p><p>The correct answer is<strong> 0.10</strong></p></div><div class="actions"><span class="score" data-score="0"></span><button class="btn btn-default btn-sm btn-xs-block text-xs-center check"><i class="fa fa-check-square-o"></i> Check</button></div></div><div class="label label-default q-number">2</div><div class="exercise shadow-bottom"><div class="q-question"><p>A gaseous sample of pure dinitrogen tetroxide (N<sub>2</sub>O<sub>4</sub>) is heated and allowed to reach equilibrium at 50°C.</p><p>N<sub>2</sub>O<sub>4(g) </sub>⇌ 2NO<sub>2</sub>(g)</p><p>If 0.500 mol of dinitrogen tetroxide (N<sub>2</sub>O<sub>4</sub>) was initially present and at equilibrium 0.050 mol of nitrogen dioxide (NO<sub>2</sub>) could be detected.</p><p>How many moles of dinitrogen tetroxide are present in the equilibrium mixture?</p></div><div class="q-answer"><p><label class="radio"> <input type="radio"> 0 mol </label></p><p><label class="radio"> <input type="radio"> 0.450 mol<span></span></label> </p><p><label class="radio"> <input type="radio"> 0.400 mol<span></span></label> </p><p><label class="radio"> <input class="c" type="radio"> <span>0.475 mol</span></label> </p></div><div class="q-explanation"><p>Using the initial-change-equilibrum (ICE) moles table:</p><table border="0" cellpadding="0" cellspacing="0" style="width:100%;"><tbody><tr><td style="text-align: center;"> </td><td style="text-align: center;">N<sub>2</sub>O<sub>4(g) </sub></td><td style="text-align: center;">⇌</td><td style="text-align: center;">2NO<sub>2</sub>(g)</td></tr><tr><td style="text-align: center;">I</td><td style="text-align: center;">0.500</td><td style="text-align: center;"> </td><td style="text-align: center;">0</td></tr><tr><td style="text-align: center;">C</td><td style="text-align: center;"><strong>2nd −0.025</strong></td><td style="text-align: center;"> </td><td style="text-align: center;"><strong>1st +0.050</strong></td></tr><tr><td style="text-align: center;">E</td><td style="text-align: center;"><strong>3rd 0.475</strong></td><td style="text-align: center;"> </td><td style="text-align: center;">0.050</td></tr><tr><td style="text-align: center;"> </td><td style="text-align: center;"> </td><td style="text-align: center;"> </td><td style="text-align: center;"> </td></tr></tbody></table><p>The non-bold information is given in the question.</p><p>We have initial and equilibrium moles of NO<sub>2</sub> so the<strong> 1st </strong>step is to calculate the change in NO<sub>2</sub>: <strong>+0.050</strong>.</p><p>If we have the change in NO<sub>2</sub> we can then calculate the change in N<sub>2</sub>O<sub>4</sub> (<strong>2nd</strong>): The mole ratio is 1:2, so two moles of NO<sub>2</sub> produced will use up one mole of N<sub>2</sub>O<sub>4</sub>. Thus 0.050 moles of NO<sub>2</sub> produced uses up (half the amount) 0.025 mol of N<sub>2</sub>O<sub>4</sub>.</p><p>We have the initial moles and change for N<sub>2</sub>O<sub>4</sub>, so lastly (<strong>3rd</strong>) we can calculate the moles of N<sub>2</sub>O<sub>4</sub> at equilibrium: 0.500−0.025=<strong>0.475</strong> mol</p><p>The correct answer is<strong> 0.475</strong></p></div><div class="actions"><span class="score" data-score="0"></span><button class="btn btn-default btn-sm btn-xs-block text-xs-center check"><i class="fa fa-check-square-o"></i> Check</button></div></div><div class="label label-default q-number">3</div><div class="exercise shadow-bottom"><div class="q-question"><p>A gaseous sample of pure dinitrogen tetroxide (N<sub>2</sub>O<sub>4</sub>) is heated in a 600cm<sup>3</sup> flask and allowed to reach equilibrium at 60°C.</p><p>N<sub>2</sub>O<sub>4(g) </sub>⇌ 2NO<sub>2</sub>(g)</p><p>If 0.400 mol of dinitrogen tetroxide (N<sub>2</sub>O<sub>4</sub>) was initially present and at equilibrium 0.200 mol of nitrogen dioxide (NO<sub>2</sub>) could be detected.</p><p>What is the value of K<sub>c</sub> under these conditions?</p></div><div class="q-answer"><p><label class="radio"> <input type="radio"> 0.666<span></span></label> </p><p><label class="radio"> <input type="radio"> 0.200</label></p><p><label class="radio"> <input type="radio"> 0.133<span></span></label> </p><p><label class="radio"> <input class="c" type="radio"> <span>0.222</span></label> </p></div><div class="q-explanation"><p>Using the initial-change-equilibrum (ICE) moles table:</p><table border="0" cellpadding="0" cellspacing="0" style="width:100%;"><tbody><tr><td style="text-align: center;"> </td><td style="text-align: center;">N<sub>2</sub>O<sub>4(g) </sub></td><td style="text-align: center;">⇌</td><td style="text-align: center;">2NO<sub>2</sub>(g)</td></tr><tr><td style="text-align: center;">I</td><td style="text-align: center;">0.400</td><td style="text-align: center;"> </td><td style="text-align: center;">0</td></tr><tr><td style="text-align: center;">C</td><td style="text-align: center;"><strong>2nd −0.100</strong></td><td style="text-align: center;"> </td><td style="text-align: center;"><strong>1st +0.200</strong></td></tr><tr><td style="text-align: center;">E</td><td style="text-align: center;"><strong>3rd 0.300</strong></td><td style="text-align: center;"> </td><td style="text-align: center;">0.200</td></tr><tr><td style="text-align: center;"> </td><td style="text-align: center;"> </td><td style="text-align: center;"> </td><td style="text-align: center;"> </td></tr></tbody></table><p>The moles of each species at equilibrium must be calculated. The non-bold information is given in the question.</p><p>We have initial and equilibrium moles of NO<sub>2</sub> so the<strong> 1st </strong>step is to calculate the change in NO<sub>2</sub>: <strong>+0.200</strong>.</p><p>If we have the change in NO<sub>2</sub> we can then calculate the change in N<sub>2</sub>O<sub>4</sub> (<strong>2nd</strong>): The mole ratio is 1:2, so two moles of NO<sub>2</sub> produced will use up one mole of N<sub>2</sub>O<sub>4</sub>. Thus 0.200 mol of NO<sub>2</sub> produced uses up 0.100 mol of N<sub>2</sub>O<sub>4</sub>.</p><p>We have the initial moles and change for N<sub>2</sub>O<sub>4</sub>, so lastly (<strong>3rd</strong>) we can calculate the moles of N<sub>2</sub>O<sub>4</sub> at equilibrium: 0.400−0.100=<strong>0.300</strong> mol</p><p>These mol values then need to be converted to concentrations (using the volume of the flask given in the question: 600cm<sup>3</sup> which is 0.600dm<sup>3</sup>).</p><p>Conc N<sub>2</sub>O<sub>4</sub> = 0.300/0.600 = 0.500moldm<sup>−3 </sup></p><p>Conc NO<sub>2</sub> = 0.300/0/600 = 0.333moldm<sup>−3 </sup></p><p>These values then need to be put into the equilibrium expression:</p><p><span class="math-tex">\(K_c = {{[NO_2]^2} \over [N_2O_4]}\)</span></p><p>K<sub>c</sub> = (0.333)<sup>2</sup>/0.500 = 0.111/0.500 = 0.222</p><p>The correct answer is therefore <strong>0.222</strong>. Units are not required for K<sub>c</sub> since it is a ratio.</p><p><strong>Incorrect answers</strong></p><p>0.666 is obtained if the [NO<sub>2</sub>] value is not squared.</p><p>0.133 is obtained if the mol values are not converted to concentrations using the total volume of 0.600dm<sup>3</sup>.</p><p>0.200 is obtained if the mole ratio is used as 1:1 in the equation and the mol values are not converted to concentrations using the total volume of 0.600dm<sup>3</sup>.</p></div><div class="actions"><span class="score" data-score="0"></span><button class="btn btn-default btn-sm btn-xs-block text-xs-center check"><i class="fa fa-check-square-o"></i> Check</button></div></div><div class="label label-default q-number">4</div><div class="exercise shadow-bottom"><div class="q-question"><p>A gaseous sample of pure iodine monobromide (IBr) is heated and allowed to reach equilibrium at 125°C.</p><p>2IBr<sub>(g) </sub>⇌ I<sub>2(g)</sub> + Br<sub>2(g)</sub></p><p>Initially there was 0.500 mol of iodine monobromide present.</p><p>At equilibrium 0.400 mol of iodine monobromide could be detected.</p><p>What is the value of K<sub>c</sub> (to three sig figs) under these conditions?</p></div><div class="q-answer"><p><label class="radio"> <input class="c" type="radio"> <span>0.016</span></label> </p><p><label class="radio"> <input type="radio"> <span>0.025</span></label> </p><p><label class="radio"> <input type="radio"> <span>0.063</span></label> </p><p><label class="radio"> <input type="radio"> <span>0.006</span></label> </p></div><div class="q-explanation"><p>Using the initial-change-equilibrum (ICE) moles table:</p><table border="0" cellpadding="0" cellspacing="0" style="width:100%;"><tbody><tr><td style="text-align: center;"> </td><td style="text-align: center;">2IBr<sub>(g)</sub></td><td style="text-align: center;">⇌</td><td style="text-align: center;">I<sub>2(g)</sub></td><td style="text-align: center;">+</td><td style="text-align: center;">Br<sub>2(g)</sub></td></tr><tr><td style="text-align: center;">I</td><td style="text-align: center;">0.500</td><td style="text-align: center;"> </td><td style="text-align: center;">0</td><td style="text-align: center;"> </td><td style="text-align: center;">0</td></tr><tr><td style="text-align: center;">C</td><td style="text-align: center;"><strong>1st −0.100</strong></td><td style="text-align: center;"> </td><td style="text-align: center;"><strong>2nd +0.050</strong></td><td style="text-align: center;"> </td><td style="text-align: center;"><strong>2nd +0.050</strong></td></tr><tr><td style="text-align: center;">E</td><td style="text-align: center;">0.400</td><td style="text-align: center;"> </td><td style="text-align: center;"><strong>3rd 0.050</strong></td><td style="text-align: center;"> </td><td style="text-align: center;"><strong>3rd 0.050</strong></td></tr><tr><td style="text-align: center;"> </td><td style="text-align: center;"> </td><td style="text-align: center;"> </td><td style="text-align: center;"> </td><td style="text-align: center;"> </td><td style="text-align: center;"> </td></tr></tbody></table><p>The moles of each species at equilibrium must be calculated. The non-bold information is given in the question.</p><p>We have initial and equilibrium moles of IBr so the<strong> 1st </strong>step is to calculate the change in IBR: <strong>−0.100</strong></p><p>If we have the change in IBr we can then calculate the change in I<sub>2</sub> and Br<sub>2 </sub>(<strong>2nd</strong>): The mole ratio is 2:1, so two moles of IBr used up will produced one mole of iodine and one mole of bromine. Thus 0.100 mol of IBr used up will produced <strong>0.050</strong> mol of both iodine and bromine.</p><p>We now have the initial moles and change for I<sub>2</sub> and Br<sub>2</sub>, so lastly (<strong>3rd</strong>) we can calculate the moles at equilibrium:<strong> 0.050</strong></p><p>Often these mol values then need to be converted to concentrations (using the volume of the flask given in the question), but here there is no volume given in the question because there are two concentration terms on top of the K<sub>c</sub> expression and two on the bottom; the volumes cancel.</p><p><span class="math-tex">\(K_c = {{[I_2][Br_2]} \over [IBr]^2}\)</span></p><p>The equilibrium mol vaules can therefore be inserted directly into the expression as 'concentrations':</p><p>K<sub>c</sub> = 0.050×0.050/(0.400)<sup>2</sup>= 0.025/0.160 = 0.015625</p><p>The correct answer is therefore <strong>0.016 </strong>to 3 sig figs. Units are not required for K<sub>c</sub> since it is a ratio.</p><p><strong>Incorrect answers</strong></p><p>0.006 is obtained if the [IBr] value is not squared.</p><p>0.063 is obtained if the mole ratio is used as 1:1 in the equation and 0.100 mol of iodine and bromine are assumed to be present at equilibrium.</p><p>0.025 is obtained if the [IBr] value is not squared and the mole ratio is used as 1:1 in the equation.</p></div><div class="actions"><span class="score" data-score="0"></span><button class="btn btn-default btn-sm btn-xs-block text-xs-center check"><i class="fa fa-check-square-o"></i> Check</button></div></div><div class="label label-default q-number">5</div><div class="exercise shadow-bottom"><div class="q-question"><p>An esterification reaction is allowed to reach equilibrium at room temperature:</p><p>carboxylic acid<sub>(aq)</sub> + alcohol<sub>(aq)</sub> ⇌ ester<sub>(aq)</sub> + water<sub>(l)</sub></p><p>The stoichiometric equation is a 1:1 ⇌ 1:1 ratio.</p><p>Initially there was 0.400 mol of carboxylic acid and 0.400 mol of alcohol present.</p><p>If at equilibrium the value of K<sub>c</sub> was found to be 4.00 what is the concentration of the alcohol at equilibrium (in moldm<sup>−3</sup>) to 3 sig figs?</p></div><div class="q-answer"><p><label class="radio"> <input type="radio"> 0.266<span></span></label> </p><p><label class="radio"> <input type="radio"> <span>0.080</span></label> </p><p><label class="radio"> <input class="c" type="radio"> <span>0.133</span></label> </p><p><label class="radio"> <input type="radio"> <span>0.320</span></label> </p></div><div class="q-explanation"><p>Note immediately that there is no volume given in the question because there are two concentration terms on top of the K<sub>c</sub> expression and two on the bottom; the volumes cancel.</p><p><span class="math-tex">\(K_c = {{[ester][water]} \over [acid][alcohol]}\)</span></p><p>Thus the mol values can be used directly in the K<sub>c</sub> expression.</p><p>Using the initial-change-equilibrum (ICE) moles table:</p><table border="0" cellpadding="0" cellspacing="0" style="width:100%;"><tbody><tr><td> </td><td style="text-align: center;">carboxylic acid<sub>(aq)</sub></td><td style="text-align: center;">+</td><td style="text-align: center;">alcohol<sub>(aq)</sub></td><td style="text-align: center;">⇌</td><td style="text-align: center;">ester<sub>(aq)</sub></td><td style="text-align: center;">+</td><td style="text-align: center;">water<sub>(l)</sub></td></tr><tr><td style="text-align: center;">I</td><td style="text-align: center;">0.400</td><td style="text-align: center;"> </td><td style="text-align: center;">0.400</td><td style="text-align: center;"> </td><td style="text-align: center;">0</td><td style="text-align: center;"> </td><td style="text-align: center;">0</td></tr><tr><td style="text-align: center;">C</td><td style="text-align: center;"><strong>0.400−<em>x</em></strong></td><td style="text-align: center;"> </td><td style="text-align: center;"><strong>0.400−<em>x</em></strong></td><td style="text-align: center;"> </td><td style="text-align: center;"><strong><em>+x</em></strong></td><td style="text-align: center;"> </td><td style="text-align: center;"><strong><em>+x</em></strong></td></tr><tr><td style="text-align: center;">E</td><td style="text-align: center;"><strong>0.400−<em>x</em></strong></td><td style="text-align: center;"> </td><td style="text-align: center;"><strong>0.400−<em>x</em></strong></td><td style="text-align: center;"> </td><td style="text-align: center;"><strong>x</strong></td><td style="text-align: center;"> </td><td style="text-align: center;"><strong>x</strong></td></tr><tr><td> </td><td style="text-align: center;"> </td><td style="text-align: center;"> </td><td style="text-align: center;"> </td><td style="text-align: center;"> </td><td style="text-align: center;"> </td><td style="text-align: center;"> </td><td style="text-align: center;"> </td></tr></tbody></table><p>The non-bold information is given in the question.</p><p>Algebra is needed. The mole ratio is 1:1 ⇌ 1:1 so the decrease in moles of each reactant will be the same as the increase in moles of each product.</p><p>Inserting the equilibrium mol values into the expression, and using the Kc value given in the question:</p><p><span class="math-tex">\(4.00 = {{x^2} \over (0.400-x)^2}\)</span></p><p>Taking square roots of each side of the equation:</p><p><span class="math-tex">\(2.00 = {{x} \over (0.400-x)}\)</span></p><p>And rearranging in terms of x:</p><p>x = 2.00(0.400−x)</p><p>x = 0.800−2x</p><p>3x = 0.800</p><p>x = 0.266</p><p>The moles of alcohol is 0.400−x = 0.400−0.266 = 0.133 (and the volumes cancel so this is the value for concentration too)</p><p>Thus the correct answer is<strong> 0.133</strong></p><p><strong>Incorrect answers</strong></p><p>0.266 is the value of x, but not the value for the alcohol.</p><p>0.320 is the value of x obtained when the 4.00 value for Kc is not square rooted, but the fraction is square rooted.</p><p>0.080 is the value for the alcohol when x is 0.320 (that is obtained when the 4.00 value for Kc is not square rooted, but the fraction is square rooted).</p></div><div class="actions"><span class="score" data-score="0"></span><button class="btn btn-default btn-sm btn-xs-block text-xs-center check"><i class="fa fa-check-square-o"></i> Check</button></div></div><div class="label label-default q-number">6</div><div class="exercise shadow-bottom"><div class="q-question"><p>The position of equilibrium for a reaction corresponds to:</p></div><div class="q-answer"><p><label class="radio"> <input type="radio"> <span>A minimum value of entropy and a minimum value of Gibb's free energy.</span></label> </p><p><label class="radio"> <input type="radio"> <span>A maximum value of entropy and a maximum value of Gibb's free energy.</span></label> </p><p><label class="radio"> <input class="c" type="radio"> <span>A maximum value of entropy and a minimum value of Gibb's free energy.</span></label> </p><p><label class="radio"> <input type="radio"> <span>A minimum value of entropy and a maximum value of Gibb's free energy. </span></label> </p></div><div class="q-explanation"><p>You need to learn that:</p><p>The position of equilibrium corresponds to a <strong>maximum value of entropy</strong> and a <strong>minimum value of Gibb's free energy.</strong></p></div><div class="actions"><span class="score" data-score="0"></span><button class="btn btn-default btn-sm btn-xs-block text-xs-center check"><i class="fa fa-check-square-o"></i> Check</button></div></div><div class="label label-default q-number">7</div><div class="exercise shadow-bottom"><div class="q-question"><p>The standard Gibb's free energy for the equilibrium reaction given below is −12.9kJmol<sup>−1</sup> at 127°C.</p><p>N<sub>2</sub>O<sub>4(g)</sub> ⇌ 2NO<sub>2</sub><sub>(g)</sub></p><p>What is the value of the equilibrium constant?</p></div><div class="q-answer"><p><label class="radio"> <input type="radio"> <span>1.00</span></label> </p><p><label class="radio"> <input type="radio"> <span>20.3×10<sup>4</sup></span></label> </p><p><label class="radio"> <input type="radio"> <span>3.88</span></label> </p><p><label class="radio"> <input class="c" type="radio"> <span>48.5</span></label> </p></div><div class="q-explanation"><p><em>ΔG° = −RTlnK </em>is given in the data book.</p><p>R is the gas constant 8.31 JK<sup>−1</sup>mol<sup>−1</sup> (also given in the data book).</p><p>T is temperature in K. 127°C is 400K (+273)</p><p>The critical thing to remember here is that <strong>ΔG is in kJ </strong>and <strong>R is in J</strong>, so best to multiply the ΔG value by 1000 to get everything into Joules.</p><p><em>ΔG° = −RTlnK </em>becomes</p><p>−12900 = −8.31×400×lnK</p><p>Rearranging:</p><p>lnK = 12900 / 8.31×400 = 3.88...</p><p>K = e<sup>3.88...</sup> = 48.5</p><p>K does not require units (it is a ratio).</p><p>The correct answer is<strong> 48.5</strong></p><p><strong>Incorrect answers</strong></p><p>20.3×10<sup>4</sup> is obtained by using 127 for T instead of 400.</p><p>1.00 is obtained by not correcting for units by multiplying by 1000: using −12.9, instead of −12900 for ΔG.</p><p>3.88 is the value of lnK (not K).</p></div><div class="actions"><span class="score" data-score="0"></span><button class="btn btn-default btn-sm btn-xs-block text-xs-center check"><i class="fa fa-check-square-o"></i> Check</button></div></div><div class="totals"><span class="score"></span><button class="btn btn-success btn-block text-center check-total"><i class="fa fa-check-square-o"></i> Check</button></div></div><hr> </div> </div> </div> </div> <div class="panel-footer"> <div> </div> </div> </div> <div class="panel panel-has-colored-body panel-default"> <div class="panel-heading"><a class="expander" href="#"><span class="fa fa-plus"></span></a> <div> <p>Exam-style questions</p> </div> </div> <div class="panel-body"> <div> <h4>Paper 1</h4> <h5>Core (SL&HL): <a href="../2155/equilibrium-core-sl-and-hl-paper-1-questions.html" title="Equilibrium core (SL and HL) paper 1 questions">Equilibrium core (SL and HL) paper 1 questions</a></h5> <h5>AHL (HL only): <a href="../2750/equilibrium-ahl-hl-only-paper-1-questions.html" title="Equilibrium AHL (HL only) paper 1 questions">Equilibrium AHL (HL only) paper 1 questions</a></h5> <h4>Paper 2</h4> <h5>Core (SL&HL): <a href="../2751/equilibrium-core-sl-hl-paper-2-questions.html" title="Equilibrium core (SL & HL) paper 2 questions">Equilibrium core (SL & HL) paper 2 questions</a></h5> <h5>AHL (HL only): <a href="../2753/equilibrium-ahl-hl-only-paper-2-questions.html" title="Equilibrium AHL (HL only) paper 2 questions">Equilibrium AHL (HL only) paper 2 questions</a></h5> </div> </div> <div class="panel-footer"> <div> </div> </div> </div> <div class="page-container panel-self-assessment" data-id="896"> <div class="panel-heading">MY PROGRESS</div> <div class="panel-body understanding-rate"> <div class="msg"></div> <label class="label-lg">Self-assessment</label><p>How much of <strong>The equilibrium law</strong> have you understood?</p><div class="slider-container text-center"><div id="self-assessment-slider" class="sib-slider self-assessment " data-value="1" data-percentage=""></div></div> <label class="label-lg">My notes</label> <textarea name="page-notes" class="form-control" rows="3" placeholder="Write your notes here..."></textarea> </div> <div class="panel-footer text-xs-center"> <span id="last-edited" class="mb-xs-3"> </span> <div class="actions mt-xs-3"> <button id="save-my-progress" type="button" class="btn btn-sm btn-primary text-center btn-xs-block"> <i class="fa fa-fw fa-floppy-o"></i> Save </button> </div> </div></div> <div id="modal-feedback" class="modal fade" tabindex="-1" role="dialog"> <div class="modal-dialog" role="document"> <div class="modal-content"> <div class="modal-header"> <h4 class="modal-title">Feedback</h4> <button type="button" class="close hidden-xs hidden-sm" data-dismiss="modal" aria-label="Close"> <span aria-hidden="true">×</span> </button> </div> <div class="modal-body"> <div class="errors"></div> <p><strong>Which of the following best describes your feedback?</strong></p> <form method="post" style="overflow: hidden"> <div class="form-group"> <div class="radio"><label style="color: #121212;"><input type="radio" name="feedback-type" value="Recommendation"> Recommend</label></div><div class="radio"><label style="color: #121212;"><input type="radio" name="feedback-type" value="Problem"> Report a problem</label></div><div class="radio"><label style="color: #121212;"><input type="radio" name="feedback-type" value="Improvement"> Suggest an improvement</label></div><div class="radio"><label style="color: #121212;"><input type="radio" name="feedback-type" value="Other"> Other</label></div> </div> <hr> <div class="row"> <div class="col-md-6"> <div class="form-group"> <label for="feedback-name">Name</label> <input type="text" class="form-control" name="feedback-name" placeholder="Name" value=" "> </div> </div> <div class="col-md-6"> <div class="form-group"> <label for="feedback-email">Email address</label> <input type="email" class="form-control" name="feedback-email" placeholder="Email" value="@airmail.cc"> </div> </div> </div> <div class="form-group"> <label for="feedback-comments">Comments</label> <textarea class="form-control" name="feedback-comments" style="resize: vertical;"></textarea> </div> <input type="hidden" name="feedback-ticket" value="082b9c9c4ae3624d"> <input type="hidden" name="feedback-url" value="https://studyib.net/chemistry/page/896/the-equilibrium-law"> <input type="hidden" name="feedback-subject" value="7"> <input type="hidden" name="feedback-subject-name" value="Chemistry"> <div class="pull-left"> </div> </form> </div> <div class="modal-footer"> <button type="button" class="btn btn-primary btn-xs-block feedback-submit mb-xs-3 pull-right"> <i class="fa fa-send"></i> Send </button> <button type="button" class="btn btn-default btn-xs-block m-xs-0 pull-left" data-dismiss="modal"> Close </button> </div> </div> </div></div> <style type="text/css" media="screen">/* Important part */
.modal-dialog{ overflow-y: initial !important
}
.modal-body{ overflow-x: auto; overflow-y: auto;
}</style><div id="modal-periodic-table" class="modal fade" tabindex="-1" role="dialog"> <div class="modal-dialog modal-lg" role="document" style="width: 90vw;"> <div class="modal-content"> <div class="modal-header"> <h4 class="modal-title">Periodic table</h4> <button type="button" class="close" data-dismiss="modal" aria-label="Close"> <span aria-hidden="true">×</span> </button> </div> <div class="modal-body"> <img src="../../../img/periodic-table/periodic-table-2020.png" style="max-width: 1400px; height: auto"> </div> <div class="modal-footer"> <button type="button" class="btn btn-default btn-xs-block m-xs-0 pull-right" data-dismiss="modal" aria-hidden="true"> Close </button> </div> </div> </div></div> </article> <hr class="hidden-md hidden-lg"> <div class="hidden-md hidden-lg mt-xs-3"> <button class="btn btn-default btn-block text-xs-center" data-toggle="modal" data-target="#modal-feedback" style="margin-bottom: 10px"><i class="fa fa-send"></i> Feedback</button> </div> </div> <input type="hidden" id="user-id" value="38342"></div><input id="ticket" type="hidden" value="082b9c9c4ae3624d"><input id="tzoffset" type="hidden" value="new"><input id="fp" class="fp" type="hidden" value=""></div><div id="std-footer"> <div class="wmap"> <div class="layout-wrapper"> <p> <a href="https://www.inthinking.net"> © <span id="footer-year"></span> <em>InThinking</em> <script>document.getElementById("footer-year").innerHTML = new Date().getFullYear();</script> </a> | <a target="_self" href="../../../about.html"> About us </a> | <a target="_self" href="../../../terms-and-conditions.html"> Legal </a> | <a target="_self" href="../../../contact.html"> Contact </a> </p> <p> <a class="social" target="_blank" href="https://twitter.com/#!/inthinker"> <img src="../../../img/social/twitter-square.svg"> Twitter </a> <a class="social" target="_blank" href="https://www.facebook.com/inthinking.net"> <img src="../../../img/social/facebook-square.svg"> Facebook </a> <a class="social" target="_blank" href="https://www.linkedin.com/profile/view?id=139741989"> <img src="../../../img/social/linkedin-square.svg"> LinkedIn </a> </p> </div> </div></div><script src="../../../js/jquery-1.11.3.min.js"></script><script src="../../../js/bootstrap.min.js"></script><script src="../../../js/jquery-fancybox/jquery.fancybox.min.js"></script><script>var pageId = 896;</script><script type="text/javascript" src="../../../js/std-galleries.min.js"></script><script type="text/javascript" src="../../../js/jqueryui/jquery-ui-custom.min.js"></script><script type="text/javascript" src="../../../js/jqueryui/jquery.ui.touch-punch.js"></script><script type="text/javascript" src="../../../js/std-quizzes-helpers.min.js?v=20220406"></script><script type="text/javascript" src="../../../js/std-quizzes.min.js?v=2022041300"></script><script type="text/javascript" src="../../../js/jqueryui/jquery-ui.min.js"></script><script type="text/javascript" src="../../../js/jqueryui/jquery.ui.touch-punch.min.js"></script><script src="../../../js/user/page-my-progress.min.js?v=202211221000"></script><script>var sAJAX='/pages/subjects/activity/user-stats-page.php?t=082b9c9c4ae3624d&p=896&s=7&x=25482';var sData='k4iA6GSB03BgPm1NwU6RPHpsE3KeSVBAEzP5PHpsE39FIxiA6GSB0bfjSYyBPm1FKYsBPYKySGBRZGi4Z0K8PYysS4PRPHpsE3KeSYcH74P5k4iRE0EBWVOFwBRD00rRPnLsSYK4ZGcR74P5EncR739RPHaL6nfhWGcjWFP5PFPRPHpsSYlFwFi7I3a1EGLj7bf4kKAh7YcHEKAhwdg30xvrZY98E0cLZGyj6HijSGr8WYcbPHr=';var loopSecs = 30;var minSecsLog = 60;var lsKey = '7-83606-896';</script><script src="../../../js/subjects/activity/user-stats-page.min.js?v=202205311700"></script><script src="../../../js/subjects/activity/my-favorites.min.js?v=20220610"></script><script src="../../../js/subjects/periodic-table.min.js"></script><script src="../../../js/subjects/feedback.min.js?v=202211221000"></script><script>var sessionUpdateSecs = 300;</script><script type="text/javascript" src="../../../js/session-updater.js"></script><script>(function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){(i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)})(window,document,'script','https://www.google-analytics.com/analytics.js','ga');ga('create', 'UA-98480796-1', 'auto');ga('send', 'pageview');</script><script src="../../../js/devicefp/devicefp.min.js"></script><script src="../../../js/jq-quickfit/jq-quickfit.min.js?v=20220201"></script><script src="../../../js/frontpage-subjects.min.js?v=202211161300"></script><script type="text/javascript" src="../../../js/studyib-jq.min.js?v=202211241300"></script><script type="text/javascript">$(document).ready(function(){ $('#trigger-modal-video-overview').click(function() { if( $('#modal-video-overview .modal-body iframe').attr('src').length == 0 ) { $('#modal-video-overview .modal-body iframe').attr('src', 'https://www.youtube.com/embed/hxxtdiLdTFk?rel=0'); } }); $('#modal-video-overview').on('hidden.bs.modal', function() { $('#modal-video-overview .modal-body iframe').attr('src', ''); }); });</script></body></html>