{"id":10713,"date":"2026-09-26T13:54:32","date_gmt":"2026-09-26T12:54:32","guid":{"rendered":"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-9-kinetics-and-equilibria\/9b-equilibria\/dynamic-equilibrium\/"},"modified":"2026-10-04T23:03:18","modified_gmt":"2026-10-04T22:03:18","slug":"dynamic-equilibrium","status":"publish","type":"page","link":"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-9-kinetics-and-equilibria\/9b-equilibria\/dynamic-equilibrium\/","title":{"rendered":"Dynamic Equilibrium"},"content":{"rendered":"\n<section class=\"ols-revision-page ols-kinetics-equilibria-page\">\n  <style>\n    .ols-revision-page {\n      --navy: #1C244B;\n      --blue: #2563eb;\n      --soft-blue: #eef4ff;\n      --soft-red: #fff7f7;\n      --soft-purple: #f7f0ff;\n      --soft-green: #f0f7f1;\n      --gold: #c9973a;\n      --grey-text: #667085;\n      --body-text: 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href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-9-kinetics-and-equilibria\/9a-kinetics\/\">Topic 9A Kinetics<\/a>\n        <ul class=\"ols-subtopic-list\">\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-9-kinetics-and-equilibria\/9a-kinetics\/collision-theory-and-rates-of-reaction\/\">Collision Theory and Rates of Reaction<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-9-kinetics-and-equilibria\/9a-kinetics\/measuring-and-calculating-rates\/\">Measuring and Calculating Rates<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-9-kinetics-and-equilibria\/9a-kinetics\/maxwell-boltzmann-distribution\/\">The Maxwell\u2013Boltzmann Distribution<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-9-kinetics-and-equilibria\/9a-kinetics\/catalysts-and-reaction-profiles\/\">Catalysts and Reaction Profiles<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/core-practicals\/cp-9a-9b-iodine-propanone-and-clock-reaction-kinetics\/\">Core Practical 9A\/9B<\/a>\n          <\/li>\n        <\/ul>\n      <\/li>\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-9-kinetics-and-equilibria\/9b-equilibria\/\">Topic 9B Equilibria<\/a>\n        <ul class=\"ols-subtopic-list\">\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-9-kinetics-and-equilibria\/9b-equilibria\/dynamic-equilibrium\/\">Dynamic Equilibrium<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-9-kinetics-and-equilibria\/9b-equilibria\/le-chateliers-principle\/\">Le Chatelier's Principle<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-9-kinetics-and-equilibria\/9b-equilibria\/equilibria-in-industry\/\">Equilibria in Industry<\/a>\n          <\/li>\n        <\/ul>\n      <\/li>\n    <\/ul>\n  <\/div>\n\n  <div class=\"ols-topic-group\">\n    <h4>Other Topics<\/h4>\n\n    <ul class=\"ols-topic-list\">\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-6-energetics\/\">Topic 6 Energetics<\/a>\n      <\/li>\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-7-intermolecular-forces\/\">Topic 7 Intermolecular Forces<\/a>\n      <\/li>\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/\">Topic 8 Redox &amp; Groups 1, 2 and 7<\/a>\n      <\/li>\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/core-practicals\/\">Core Practicals<\/a>\n      <\/li>\n    <\/ul>\n  <\/div>\n<\/aside>\n\n<script>\r\n(function() {\r\n  function normalisePath(path) {\r\n    return String(path || '')\r\n      .split('?')[0]\r\n      .split('#')[0]\r\n      .replace(\/\\\/+$\/, '')\r\n      .toLowerCase();\r\n  }\r\n\r\n  function highlightActive() {\r\n    var sidebar = document.querySelector('.ols-sidebar');\r\n    if (!sidebar) return false;\r\n\r\n    var currentPath = normalisePath(window.location.pathname);\r\n    var links = sidebar.querySelectorAll('a[href]');\r\n    var matched = null;\r\n    var matchedLength = 0;\r\n\r\n    sidebar.querySelectorAll('.active, .active-main, .parent-active').forEach(function(item) {\r\n      item.classList.remove('active', 'active-main', 'parent-active');\r\n    });\r\n\r\n    sidebar.querySelectorAll('a[data-ols-disabled-parent=\"1\"], a[aria-current]').forEach(function(a) {\r\n      a.removeAttribute('aria-current');\r\n      a.removeAttribute('tabindex');\r\n      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}\r\n})();\r\n<\/script>\r\n\n\n    <main class=\"ols-main\">\n\n      <!-- BREADCRUMBS - updated with full path and correct links -->\n      <nav class=\"ols-breadcrumbs\" aria-label=\"Breadcrumb\">\n<a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/\">Revision Notes<\/a> \/\n<a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/\">A Level Chemistry<\/a> \/\n<a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/\">Edexcel International<\/a> \/\n<a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-9-kinetics-and-equilibria\/\">Topic 9 Kinetics and Equilibria<\/a> \/\n<a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-9-kinetics-and-equilibria\/9b-equilibria\/\">Topic 9B Equilibria<\/a> \/\n<span>Dynamic Equilibrium<\/span>\n<\/nav>\n\n      <header class=\"ols-title-card\">\n        <h1>Dynamic Equilibrium<\/h1>\n        <p class=\"ols-page-intro\">A concise revision guide to reversible reactions and dynamic equilibrium: the two features of equilibrium, the need for a closed system, the position of equilibrium and the rate and concentration graphs as equilibrium is reached.<\/p>\n        <div class=\"ols-badges\">\n<div class=\"ols-badge\">Exam board: Edexcel International<\/div>\n<div class=\"ols-badge\">Unit 2: WCH12\/01<\/div>\n<div class=\"ols-badge\">Topic 9B Equilibria<\/div>\n<\/div>\n        <div class=\"ols-author\">\n\n    <img decoding=\"async\"\n      class=\"ols-author-avatar-img\"\n      src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/05\/Author-Profile.jpeg\"\n      alt=\"Dr. Mohammed Al-Fatah\"\n    >\n\n    <div class=\"ols-author-content\">\n\n      <h2 class=\"ols-author-title\">\n        Written by: Dr. Mohammed Al-Fatah\n      <\/h2>\n\n      <p class=\"ols-author-description\">\n        Chemistry specialist revision notes for A Level Chemistry.\n      <\/p>\n\n      <a class=\"ols-linkedin-pill\" href=\"https:\/\/www.linkedin.com\/in\/doctormohammedfatah\/\" target=\"_blank\" rel=\"noopener noreferrer\">\n        <svg class=\"ols-linkedin-icon\" viewBox=\"0 0 24 24\" fill=\"currentColor\" aria-hidden=\"true\">\n          <path d=\"M4.98 3.5C4.98 4.88 3.86 6 2.48 6S0 4.88 0 3.5 1.12 1 2.48 1s2.5 1.12 2.5 2.5zM.5 8h4V24h-4V8zm7 0h3.8v2.2h.1c.5-.9 1.8-2.2 3.9-2.2 4.2 0 5 2.8 5 6.4V24h-4v-7.6c0-1.8 0-4.2-2.6-4.2s-3 2-3 4v7.8h-4V8z\"\/>\n        <\/svg>\n        View LinkedIn Profile\n      <\/a>\n\n    <\/div>\n\n  <\/div>\n      <\/header>\n\n      <section class=\"ols-h5p-card ols-h5p-inline ols-h5p-recap\">\n<span class=\"ols-h5p-kicker\">Before you start<\/span>\n<h2>GCSE Recap: Reversible Reactions<\/h2>\n<p>Three quick questions on reversible reactions and the \u21cc sign from GCSE.<\/p>\n<div class=\"ols-h5p-frame\"><div class=\"h5p-content\" data-content-id=\"911\"><\/div><\/div>\n<\/section>\n<article class=\"ols-note-card\">\n<div class=\"ols-note-title\">\n<div class=\"ols-note-icon\">1<\/div>\n<h2>Reversible Reactions<\/h2>\n<\/div>\n<p>Many reactions are <strong>reversible<\/strong>: the products can react together to re-form the reactants.<\/p><p>Blue hydrated copper(II) sulfate loses its water on heating to give the white anhydrous salt, and the white salt turns blue again when water is added.<\/p><p>Reversible reactions are written with the equilibrium sign, \u21cc. The reaction from left to right is called the <strong>forward reaction<\/strong>, the one from right to left the <strong>reverse (backward) reaction<\/strong>.<\/p>\n<p>If the forward reaction is exothermic, the reverse reaction is endothermic by exactly the same amount, because the same bonds are broken and made in the opposite direction.<\/p>\n<div class=\"ols-key-box\">\n<p><strong>Key idea:<\/strong> A reversible reaction can go in either direction. Which direction dominates depends on the conditions.<\/p>\n<\/div>\n<div class=\"ols-figure-card ols-zoom-pop\">\n<div class=\"ols-figure-image\">\n<a class=\"ols-image-fullscreen-link\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/09\/t9x-reversecuso4.jpg\" target=\"_blank\" rel=\"noopener\" aria-label=\"Open image fullscreen\">\n<img decoding=\"async\" src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/09\/t9x-reversecuso4.jpg\" alt=\"Cycle showing blue hydrated copper sulfate heated to white anhydrous powder and turned blue again by adding water.\" data-fullscreen-src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/09\/t9x-reversecuso4.jpg\">\n<\/a>\n<\/div>\n<div class=\"ols-figure-caption\"><p>Hydrated copper(II) sulfate shows a reversible reaction: heating drives off water to leave white anhydrous powder, and adding water turns it blue again with an equal and opposite energy change.<\/p><\/div>\n<\/div>\n<\/article>\n<article class=\"ols-note-card soft\">\n<div class=\"ols-note-title\">\n<div class=\"ols-note-icon\">2<\/div>\n<h2>The Two Features of Dynamic Equilibrium<\/h2>\n<\/div>\n<p>Suppose a reversible reaction is started with only reactants in a <strong>closed system<\/strong>, one that nothing can enter or leave.<\/p><p>At first the forward reaction is fast, because the reactants are concentrated, and the reverse reaction cannot happen at all because there are no products.<\/p><p>As products build up the reverse reaction gets faster, and as reactants are used up the forward reaction gets slower, until the two rates are equal. From then on the mixture is at <strong>dynamic equilibrium<\/strong>.<\/p>\n<p>Dynamic equilibrium has two features that must both be stated:<\/p>\n<ul><li>the <strong>rate of the forward reaction equals the rate of the reverse reaction<\/strong>;<\/li><li>the <strong>concentrations of reactants and products remain constant<\/strong> (constant, not necessarily equal).<\/li><\/ul>\n<p>The word <strong>dynamic<\/strong> matters. Nothing looks to be happening, but both reactions are still going on at the same rate, so there is no overall change. It is like walking up a down escalator at the speed of the escalator: plenty of movement, no change in position.<\/p>\n<div class=\"ols-figure-card ols-zoom-pop\">\n<div class=\"ols-figure-image\">\n<a class=\"ols-image-fullscreen-link\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/09\/kinetics-equilibria-dynamic-equilibrium-graphs.jpg\" target=\"_blank\" rel=\"noopener\" aria-label=\"Open image fullscreen\">\n<img decoding=\"async\" src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/09\/kinetics-equilibria-dynamic-equilibrium-graphs.jpg\" alt=\"Graphs against time for a reaction reaching dynamic equilibrium: forward and reverse rates becoming equal and concentrations levelling off\" data-fullscreen-src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/09\/kinetics-equilibria-dynamic-equilibrium-graphs.jpg\">\n<\/a>\n<\/div>\n<div class=\"ols-figure-caption\"><p>The forward and reverse rates becoming equal, and the reactant and product concentrations levelling off, as a closed system reaches equilibrium.<\/p><\/div>\n<\/div>\n<div class=\"ols-key-box\">\n<p><strong>Definition:<\/strong> Dynamic equilibrium: in a closed system, the forward and reverse reactions occur at equal rates and the concentrations of reactants and products stay constant.<\/p>\n<\/div>\n<\/article>\n<section class=\"ols-h5p-card ols-h5p-inline\">\n<span class=\"ols-h5p-kicker\">Check your understanding<\/span>\n<h2>Check: Features of Equilibrium<\/h2>\n<p>Decide which statements describe a system at dynamic equilibrium.<\/p>\n<div class=\"ols-h5p-frame\"><div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-912\" class=\"h5p-iframe\" data-content-id=\"912\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Kinetics and Equilibria Summary: Features of Equilibrium\"><\/iframe><\/div><\/div>\n<\/section>\n<article class=\"ols-note-card\">\n<div class=\"ols-note-title\">\n<div class=\"ols-note-icon\">3<\/div>\n<h2>Why the System Must Be Closed<\/h2>\n<\/div>\n<p>Equilibrium can only be reached if none of the substances can escape. In an open flask a gaseous product leaves, so the reverse reaction can never build up to match the forward reaction and the reaction simply goes to completion.<\/p><p>Heating calcium carbonate in an open kiln gives calcium oxide and carbon dioxide until the carbonate is gone.<\/p><p>In a sealed vessel the carbon dioxide stays, the reverse reaction takes place, and an equilibrium is set up.<\/p>\n<p>The <strong>position of equilibrium<\/strong> describes the make-up of the equilibrium mixture. If it lies to the right, the mixture is mostly products; if to the left, mostly reactants.<\/p><p>The position depends on the temperature, and for many reactions on the pressure and concentrations, which is the subject of the next page.<\/p>\n<!-- 3D card: dynamic-equilibrium (26 Sep 2026) -->\n<!-- Copyright (c) 2026 Dr. Mohammed Al-Fatah, onlinelearningsystem.net. 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text-align:center; font-size:11px; font-style:italic; color:#aab0c0;\n}\n.ols-cc-deq-001 a{color:#aab0c0; text-decoration:none;}\n.ols-cc-deq-001 a:hover{text-decoration:underline;}\n<\/style>\n\n<div class=\"deq-head\">\n  <h2 class=\"deq-title\">Dynamic Equilibrium in a Closed System<\/h2>\n  <p class=\"deq-sub\">Watch colourless N<sub>2<\/sub>O<sub>4<\/sub> split into brown NO<sub>2<\/sub> and NO<sub>2<\/sub> pair up again in a sealed box, until both reactions run at the same rate and the amounts stop changing.<\/p>\n<\/div>\n\n<div class=\"deq-stage\" id=\"deqStage\">\n  <canvas class=\"deq-canvas\" id=\"deqCanvas\"><\/canvas>\n  <div class=\"deq-overlay\" id=\"deqOverlay\"><\/div>\n  <div class=\"deq-caption\" id=\"deqCaption\"><\/div>\n  <div class=\"deq-hint\" id=\"deqHint\">Drag to rotate<\/div>\n  <div class=\"deq-badges\" id=\"deqBadges\"><\/div>\n<\/div>\n\n<div class=\"deq-controls\">\n  <div class=\"deq-row\">\n    <span class=\"deq-rowlab\">Step<\/span>\n    <div class=\"deq-seg\" role=\"group\" aria-label=\"Step\">\n      <button type=\"button\" data-step=\"1\" aria-pressed=\"true\">Start<\/button>\n      <button type=\"button\" data-step=\"2\" aria-pressed=\"false\">Reacting<\/button>\n      <button type=\"button\" data-step=\"3\" aria-pressed=\"false\">Equilibrium<\/button>\n      <button type=\"button\" data-step=\"4\" aria-pressed=\"false\">Heat<\/button>\n      <button type=\"button\" data-step=\"5\" aria-pressed=\"false\">Compress<\/button>\n      <button type=\"button\" data-step=\"6\" aria-pressed=\"false\">Open lid<\/button>\n    <\/div>\n  <\/div>\n\n  <div class=\"deq-row\">\n    <span class=\"deq-rowlab\">View<\/span>\n    <button type=\"button\" class=\"deq-pill\" id=\"deqResetV\">Reset view<\/button>\n  <\/div>\n<\/div>\n\n<div class=\"deq-info\">\n  <h3 id=\"deqInfoTitle\"><\/h3>\n  <p id=\"deqInfoText\"><\/p>\n  <div class=\"deq-facts\" id=\"deqFacts\"><\/div>\n  <div class=\"deq-key\">\n    <span><i style=\"background:#b9c8e6\"><\/i>N<sub>2<\/sub>O<sub>4<\/sub>, colourless (N pale blue, O pale red)<\/span>\n    <span><i style=\"background:#9a4f1c\"><\/i>NO<sub>2<\/sub>, brown<\/span>\n    <span><i style=\"background:#e83c34\"><\/i>Bond breaking<\/span>\n    <span><i style=\"background:#38b258\"><\/i>Bond forming<\/span>\n    <span><i style=\"background:rgba(150,80,30,0.3); border:1.5px solid rgba(28,36,75,0.5)\"><\/i>Sealed container<\/span>\n    <span><i style=\"background:#2563eb\"><\/i>Forward rate<\/span>\n    <span><i style=\"background:#b4531a\"><\/i>Reverse rate<\/span>\n  <\/div>\n<\/div>\n<\/section>\n\n<p class=\"ols-cc-deq-001\">&copy; Dr. Mohammed Al-Fatah &#8211; <a href=\"https:\/\/www.onlinelearningsystem.net\" target=\"_blank\" rel=\"noopener\">onlinelearningsystem.net<\/a><\/p>\n<script src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/JS\/dynamic-equilibrium.js?v=20261003d\"><\/script>\n\n<div class=\"ols-key-box\">\n<p><strong>Exam wording:<\/strong> &#8220;Closed system&#8221; means no substance can enter or leave. Energy can still be exchanged with the surroundings; a closed system is not an insulated one.<\/p>\n<\/div>\n<\/article>\n<section class=\"ols-h5p-card ols-h5p-inline\">\n<span class=\"ols-h5p-kicker\">Check your understanding<\/span>\n<h2>Check: Closed Systems and Position<\/h2>\n<p>Apply the ideas to systems that are not described on this page.<\/p>\n<div class=\"ols-h5p-frame\"><div class=\"h5p-content\" data-content-id=\"913\"><\/div><\/div>\n<\/section>\n<section class=\"ols-faq-card\">\n<h2>FAQs<\/h2>\n<p>Use these quick answers to check the equilibrium ideas.<\/p>\n\n<div class=\"ols-faq-list\">\n<div class=\"ols-faq-item\">\n<h3>Are the concentrations of reactants and products equal at equilibrium?<\/h3>\n<p>Not usually. They are constant, meaning they stop changing, but the mixture may be mostly products or mostly reactants depending on the position of equilibrium.<\/p>\n<\/div>\n\n<div class=\"ols-faq-item\">\n<h3>Has the reaction stopped at equilibrium?<\/h3>\n<p>No. Both the forward and reverse reactions continue at the same rate, so there is no overall change. That is what &#8220;dynamic&#8221; means.<\/p>\n<\/div>\n\n<div class=\"ols-faq-item\">\n<h3>Why must the system be closed?<\/h3>\n<p>If a product escapes, the reverse reaction can never catch up with the forward reaction, so equilibrium is never reached and the reaction goes to completion.<\/p>\n<\/div>\n\n<div class=\"ols-faq-item\">\n<h3>Can equilibrium be reached starting from the products?<\/h3>\n<p>Yes. The same equilibrium mixture is reached from either side at the same temperature, which is one of the tests that a true equilibrium has been established.<\/p>\n<\/div>\n\n<div class=\"ols-faq-item\">\n<h3>What does &#8220;position of equilibrium&#8221; mean?<\/h3>\n<p>The composition of the equilibrium mixture. A position to the right means mostly products; to the left means mostly reactants.<\/p>\n<\/div>\n<\/div>\n<\/section>\n<section class=\"ols-related-card\">\n<h2>Related Topic 9B Equilibria Pages<\/h2>\n<p>Use these pages to connect the ideas across equilibria and the rest of Topic 9.<\/p>\n<div class=\"ols-related-grid\">\n<a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-9-kinetics-and-equilibria\/9b-equilibria\/le-chateliers-principle\/\">Le Chatelier&#8217;s Principle<\/a>\n<a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-9-kinetics-and-equilibria\/9b-equilibria\/equilibria-in-industry\/\">Equilibria in Industry<\/a>\n<a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-9-kinetics-and-equilibria\/9b-equilibria\/\">Topic 9B Equilibria Overview<\/a>\n<\/div>\n<\/section>\n<section class=\"ols-attribution-card\">\n        <p><strong>Copyright notice:<\/strong> This OLS revision content, including the explanations, layout, diagrams, tables and embedded learning structure, is authored for Online Learning System by Dr. Mohammed Al-Fatah. 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