{"id":5272,"date":"2026-06-19T04:54:50","date_gmt":"2026-06-19T03:54:50","guid":{"rendered":"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-2-amount-of-substance\/"},"modified":"2026-06-24T08:47:07","modified_gmt":"2026-06-24T07:47:07","slug":"3-1-2-amount-of-substance","status":"publish","type":"page","link":"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-2-amount-of-substance\/","title":{"rendered":"3.1.2 Amount of Substance"},"content":{"rendered":"\n<div class=\"ols-aqa312-page\">\n\n  <aside class=\"ols-sidebar\">\r\n  <div class=\"ols-sidebar-header\">\r\n    <h3>Revision Notes<\/h3>\r\n    <p>AQA A Level Chemistry<\/p>\r\n  <\/div>\r\n\r\n  <div class=\"ols-topic-group\">\r\n    <h4>3.1.2 Amount of Substance<\/h4>\r\n\r\n    <ul class=\"ols-topic-list\">\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-2-amount-of-substance\/relative-masses\/\">Relative Masses<\/a>\r\n      <\/li>\r\n\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-2-amount-of-substance\/the-mole-and-avogadro-constant\/\">The Mole and Avogadro Constant<\/a>\r\n      <\/li>\r\n\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-2-amount-of-substance\/empirical-and-molecular-formulae\/\">Empirical and Molecular Formulae<\/a>\r\n\r\n        <ul class=\"ols-subtopic-list\">\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-2-amount-of-substance\/empirical-and-molecular-formulae\/empirical-formula\/\">Empirical Formula<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-2-amount-of-substance\/empirical-and-molecular-formulae\/molecular-formula\/\">Molecular Formula<\/a>\r\n          <\/li>\r\n        <\/ul>\r\n      <\/li>\r\n\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-2-amount-of-substance\/chemical-equations-and-reacting-masses\/\">Chemical Equations and Reacting Masses<\/a>\r\n\r\n        <ul class=\"ols-subtopic-list\">\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-2-amount-of-substance\/chemical-equations-and-reacting-masses\/writing-chemical-equations\/\">Writing Chemical Equations<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-2-amount-of-substance\/chemical-equations-and-reacting-masses\/ionic-equations\/\">Ionic Equations<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-2-amount-of-substance\/chemical-equations-and-reacting-masses\/calculations-using-reacting-masses\/\">Calculations Using Reacting Masses<\/a>\r\n          <\/li>\r\n        <\/ul>\r\n      <\/li>\r\n\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-2-amount-of-substance\/concentration-and-titration-calculations\/\">Concentration and Titration Calculations<\/a>\r\n\r\n        <ul class=\"ols-subtopic-list\">\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-2-amount-of-substance\/concentration-and-titration-calculations\/concentrations-of-solutions\/\">Concentrations of Solutions<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-2-amount-of-substance\/concentration-and-titration-calculations\/titration-calculations\/\">Titration Calculations<\/a>\r\n          <\/li>\r\n        <\/ul>\r\n      <\/li>\r\n\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-2-amount-of-substance\/gas-volumes-and-the-ideal-gas-equation\/\">Gas Volumes and the Ideal Gas Equation<\/a>\r\n      <\/li>\r\n\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-2-amount-of-substance\/percentage-yield\/\">Percentage Yield<\/a>\r\n      <\/li>\r\n\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-2-amount-of-substance\/atom-economy\/\">Atom Economy<\/a>\r\n      <\/li>\r\n    <\/ul>\r\n  <\/div>\r\n\r\n  <div class=\"ols-topic-group\">\r\n    <h4>Adjacent Topics<\/h4>\r\n\r\n    <ul class=\"ols-topic-list\">\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-1-atomicstructure\/\">3.1.1 Atomic Structure<\/a>\r\n      <\/li>\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-3-bonding\/\">3.1.3 Bonding<\/a>\r\n      <\/li>\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-4-energetics\/\">3.1.4 Energetics<\/a>\r\n      <\/li>\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-2-1-periodicity\/\">3.2.1 Periodicity<\/a>\r\n      <\/li>\r\n    <\/ul>\r\n  <\/div>\r\n<\/aside>\r\n\r\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\"], 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border: 1px solid rgba(168, 85, 247, 0.18); }\n    .ols-aqa312-spec-mob-row--mid { background: #f5f0ff; border: 1px solid rgba(168, 85, 247, 0.22); }\n    .ols-aqa312-spec-mob-code { background: #3b0764; color: #ffffff; font-size: 15px; font-weight: 800; text-align: center; height: 34px; line-height: 34px; }\n    .ols-aqa312-spec-mob-code--mid { background: #581c87; }\n    .ols-aqa312-spec-mob-text { padding: 16px 18px; font-size: 15px; font-weight: 300; line-height: 1.8; color: #3f314c; }\n    .ols-aqa312-spec-mob-sub-list { display: flex; flex-direction: column; gap: 9px; margin-top: 10px; }\n    .ols-aqa312-spec-mob-sub-row { background: #ffffff; border: 1px solid rgba(168, 85, 247, 0.15); border-radius: 12px; overflow: hidden; }\n    .ols-aqa312-spec-mob-sub-code { background: #c084fc; color: #3b0764; font-size: 13px; font-weight: 800; text-align: center; height: 30px; line-height: 30px; }\n    .ols-aqa312-spec-mob-sub-text { padding: 12px 16px; font-size: 14px; font-weight: 300; line-height: 1.8; color: #4b3b58; }\n\n    @media (max-width: 1100px) { .ols-aqa312-cards-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); } }\n    @media (max-width: 860px) { .ols-aqa312-intro-inner { grid-template-columns: 1fr; gap: 40px; } }\n    @media (max-width: 640px) {\n      .ols-aqa312-intro { padding: 24px 0 52px; }\n      .ols-aqa312-topics { padding: 52px 0 58px; }\n      .ols-aqa312-cards-grid { grid-template-columns: 1fr; gap: 14px; }\n      .ols-aqa312-spec-section { padding: 52px 0 64px; }\n      .ols-aqa312-spec-wrap { padding: 24px 18px; border-radius: 20px; }\n      .ols-aqa312-info-grid { grid-template-columns: 1fr 1fr; }\n    }\n  <\/style>\n\n  <!-- BREADCRUMB BAR - sits above everything -->\n  <div class=\"ols-aqa312-breadcrumb-bar\">\n    <div class=\"ols-aqa312-container\">\n      <nav class=\"ols-aqa312-breadcrumb\" 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\/aqa\/\">AQA<\/a> \/\n        <span>3.1.2 Amount of Substance<\/span>\n      <\/nav>\n    <\/div>\n  <\/div>\n\n  <!-- INTRO -->\n  <section class=\"ols-aqa312-intro\">\n    <div class=\"ols-aqa312-container\">\n      <div class=\"ols-aqa312-intro-inner\">\n        <div>\n          <div class=\"ols-aqa312-eyebrow\">AQA A Level Chemistry<\/div>\n          <h1>3.1.2<br>Amount of<br>Substance<\/h1>\n          <div class=\"ols-aqa312-accent-bar\"><\/div>\n          <p class=\"ols-aqa312-intro-lead\">\n            AQA 3.1.2 develops the quantitative language of chemistry. This topic covers relative masses, the mole, Avogadro constant, empirical and molecular formulae, balanced equations, reacting masses, solution concentrations, titration calculations, gas volumes, percentage yield and atom economy.\n          <\/p>\n        <\/div>\n\n        <div class=\"ols-aqa312-info-grid\">\n          <div class=\"ols-aqa312-info-card\"><div class=\"ols-aqa312-info-card-label\">Exam Papers<\/div><div class=\"ols-aqa312-info-card-value\">Paper 1 &amp; 2<\/div><div class=\"ols-aqa312-info-card-sub\">7405\/1 and 7405\/2<\/div><\/div>\n          <div class=\"ols-aqa312-info-card\"><div class=\"ols-aqa312-info-card-label\">Specification Points<\/div><div class=\"ols-aqa312-info-card-value\">3.1.2.1 &#8211; 3.1.2.5<\/div><div class=\"ols-aqa312-info-card-sub\">5 AQA sections<\/div><\/div>\n          <div class=\"ols-aqa312-info-card\"><div class=\"ols-aqa312-info-card-label\">Topic Parts<\/div><div class=\"ols-aqa312-info-card-value\">8 parts<\/div><div class=\"ols-aqa312-info-card-sub\">Revision notes available<\/div><\/div>\n          <div class=\"ols-aqa312-info-card\"><div class=\"ols-aqa312-info-card-label\">Exam Board<\/div><div class=\"ols-aqa312-info-card-value\">AQA<\/div><div class=\"ols-aqa312-info-card-sub\">AQA 7405<\/div><\/div>\n        <\/div>\n      <\/div>\n    <\/div>\n  <\/section>\n\n  <!-- TOPIC CARDS -->\n  <section class=\"ols-aqa312-topics\">\n    <div class=\"ols-aqa312-container\">\n      <div class=\"ols-aqa312-section-header\">\n        <h2 class=\"ols-aqa312-section-title\">Revision Notes<\/h2>\n        <p class=\"ols-aqa312-section-sub\">Work through each part of AQA 3.1.2 in a structured sequence.<\/p>\n      <\/div>\n\n      <div class=\"ols-aqa312-cards-grid\">\n\n        <!-- Card 1: Relative Masses -->\n        <a class=\"ols-aqa312-card ols-aqa312-card--available\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-2-amount-of-substance\/relative-masses\/\">\n          <div class=\"ols-aqa312-card-img-wrap\">\n            <div class=\"ols-aqa312-visual ols-aqa312-visual--one\">\n              <div class=\"ols-aqa312-visual-panel\">\n                <div class=\"ols-aqa312-visual-kicker\">Relative masses<\/div>\n                <div class=\"ols-aqa312-visual-main\">Relative<br>Masses<\/div>\n                <div class=\"ols-aqa312-config-line\" aria-hidden=\"true\"><span>Ar \/ Mr<\/span><\/div>\n              <\/div>\n            <\/div>\n            <div class=\"ols-aqa312-card-num\">1<\/div>\n            <span class=\"ols-aqa312-card-status ols-aqa312-card-status--available\">Available<\/span>\n          <\/div>\n          <div class=\"ols-aqa312-card-body\">\n            <p class=\"ols-aqa312-card-title\">Relative Masses<\/p>\n            <p class=\"ols-aqa312-card-desc\">Relative atomic mass, relative molecular mass and relative formula mass in terms of carbon-12.<\/p>\n            <span class=\"ols-aqa312-card-cta\">\n              Start revising\n              <svg viewBox=\"0 0 16 16\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><path d=\"M3 8h10M9 4l4 4-4 4\"><\/path><\/svg>\n            <\/span>\n          <\/div>\n        <\/a>\n\n        <!-- Card 2: The Mole and Avogadro Constant -->\n        <a class=\"ols-aqa312-card ols-aqa312-card--available\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-2-amount-of-substance\/the-mole-and-avogadro-constant\/\">\n          <div class=\"ols-aqa312-card-img-wrap\">\n            <div class=\"ols-aqa312-visual ols-aqa312-visual--two\">\n              <div class=\"ols-aqa312-visual-panel\">\n                <div class=\"ols-aqa312-visual-kicker\">Particles and moles<\/div>\n                <div class=\"ols-aqa312-visual-main\">Mole &#038;<br>Avogadro<\/div>\n                <div class=\"ols-aqa312-config-line\" aria-hidden=\"true\"><span>mol<\/span><\/div>\n              <\/div>\n            <\/div>\n            <div class=\"ols-aqa312-card-num\">2<\/div>\n            <span class=\"ols-aqa312-card-status ols-aqa312-card-status--available\">Available<\/span>\n          <\/div>\n          <div class=\"ols-aqa312-card-body\">\n            <p class=\"ols-aqa312-card-title\">The Mole and Avogadro Constant<\/p>\n            <p class=\"ols-aqa312-card-desc\">The mole, Avogadro constant, particles, amount of substance, mass and solution concentration.<\/p>\n            <span class=\"ols-aqa312-card-cta\">\n              Start revising\n              <svg viewBox=\"0 0 16 16\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><path d=\"M3 8h10M9 4l4 4-4 4\"><\/path><\/svg>\n            <\/span>\n          <\/div>\n        <\/a>\n\n        <!-- Card 3: Empirical and Molecular Formulae -->\n        <a class=\"ols-aqa312-card ols-aqa312-card--available\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-2-amount-of-substance\/empirical-and-molecular-formulae\/\">\n          <div class=\"ols-aqa312-card-img-wrap\">\n            <div class=\"ols-aqa312-visual ols-aqa312-visual--three\">\n              <div class=\"ols-aqa312-visual-panel\">\n                <div class=\"ols-aqa312-visual-kicker\">Formula ratios<\/div>\n                <div class=\"ols-aqa312-visual-main\">Formula<br>Ratios<\/div>\n                <div class=\"ols-aqa312-config-line\" aria-hidden=\"true\"><span>EF \u2192 MF<\/span><\/div>\n              <\/div>\n            <\/div>\n            <div class=\"ols-aqa312-card-num\">3<\/div>\n            <span class=\"ols-aqa312-card-status ols-aqa312-card-status--available\">Available<\/span>\n          <\/div>\n          <div class=\"ols-aqa312-card-body\">\n            <p class=\"ols-aqa312-card-title\">Empirical and Molecular Formulae<\/p>\n            <p class=\"ols-aqa312-card-desc\">Empirical formulae, molecular formulae and the relationship between simplest ratio and actual formula.<\/p>\n            <span class=\"ols-aqa312-card-cta\">\n              Start revising\n              <svg viewBox=\"0 0 16 16\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><path d=\"M3 8h10M9 4l4 4-4 4\"><\/path><\/svg>\n            <\/span>\n          <\/div>\n        <\/a>\n\n        <!-- Card 4: Chemical Equations and Reacting Masses -->\n        <a class=\"ols-aqa312-card ols-aqa312-card--available\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-2-amount-of-substance\/chemical-equations-and-reacting-masses\/\">\n          <div class=\"ols-aqa312-card-img-wrap\">\n            <div class=\"ols-aqa312-visual ols-aqa312-visual--four\">\n              <div class=\"ols-aqa312-visual-panel\">\n                <div class=\"ols-aqa312-visual-kicker\">Stoichiometry<\/div>\n                <div class=\"ols-aqa312-visual-main\">Reacting<br>Masses<\/div>\n                <div class=\"ols-aqa312-config-line\" aria-hidden=\"true\"><span>n \u2194 m<\/span><\/div>\n              <\/div>\n            <\/div>\n            <div class=\"ols-aqa312-card-num\">4<\/div>\n            <span class=\"ols-aqa312-card-status ols-aqa312-card-status--available\">Available<\/span>\n          <\/div>\n          <div class=\"ols-aqa312-card-body\">\n            <p class=\"ols-aqa312-card-title\">Chemical Equations and Reacting Masses<\/p>\n            <p class=\"ols-aqa312-card-desc\">Balanced equations, ionic equations and calculations involving masses from chemical equations.<\/p>\n            <span class=\"ols-aqa312-card-cta\">\n              Start revising\n              <svg viewBox=\"0 0 16 16\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><path d=\"M3 8h10M9 4l4 4-4 4\"><\/path><\/svg>\n            <\/span>\n          <\/div>\n        <\/a>\n\n        <!-- Card 5: Concentration and Titration Calculations -->\n        <a class=\"ols-aqa312-card ols-aqa312-card--available\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-2-amount-of-substance\/concentration-and-titration-calculations\/\">\n          <div class=\"ols-aqa312-card-img-wrap\">\n            <div class=\"ols-aqa312-visual ols-aqa312-visual--five\">\n              <div class=\"ols-aqa312-visual-panel\">\n                <div class=\"ols-aqa312-visual-kicker\">Solutions<\/div>\n                <div class=\"ols-aqa312-visual-main\">Titration<br>Calcs<\/div>\n                <div class=\"ols-aqa312-config-line\" aria-hidden=\"true\"><span>cV = n<\/span><\/div>\n              <\/div>\n            <\/div>\n            <div class=\"ols-aqa312-card-num\">5<\/div>\n            <span class=\"ols-aqa312-card-status ols-aqa312-card-status--available\">Available<\/span>\n          <\/div>\n          <div class=\"ols-aqa312-card-body\">\n            <p class=\"ols-aqa312-card-title\">Concentration and Titration Calculations<\/p>\n            <p class=\"ols-aqa312-card-desc\">Concentration in mol dm\u207b\u00b3, solution volumes and titration-style amount of substance calculations.<\/p>\n            <span class=\"ols-aqa312-card-cta\">\n              Start revising\n              <svg viewBox=\"0 0 16 16\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><path d=\"M3 8h10M9 4l4 4-4 4\"><\/path><\/svg>\n            <\/span>\n          <\/div>\n        <\/a>\n\n        <!-- Card 6: Gas Volumes and the Ideal Gas Equation -->\n        <a class=\"ols-aqa312-card ols-aqa312-card--available\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-2-amount-of-substance\/gas-volumes-and-the-ideal-gas-equation\/\">\n          <div class=\"ols-aqa312-card-img-wrap\">\n            <div class=\"ols-aqa312-visual ols-aqa312-visual--six\">\n              <div class=\"ols-aqa312-visual-panel\">\n                <div class=\"ols-aqa312-visual-kicker\">Gases<\/div>\n                <div class=\"ols-aqa312-visual-main\">Gas<br>Equation<\/div>\n                <div class=\"ols-aqa312-config-line\" aria-hidden=\"true\"><span>pV=nRT<\/span><\/div>\n              <\/div>\n            <\/div>\n            <div class=\"ols-aqa312-card-num\">6<\/div>\n            <span class=\"ols-aqa312-card-status ols-aqa312-card-status--available\">Available<\/span>\n          <\/div>\n          <div class=\"ols-aqa312-card-body\">\n            <p class=\"ols-aqa312-card-title\">Gas Volumes and the Ideal Gas Equation<\/p>\n            <p class=\"ols-aqa312-card-desc\">Gas volume calculations and use of pV = nRT with variables in SI units.<\/p>\n            <span class=\"ols-aqa312-card-cta\">\n              Start revising\n              <svg viewBox=\"0 0 16 16\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><path d=\"M3 8h10M9 4l4 4-4 4\"><\/path><\/svg>\n            <\/span>\n          <\/div>\n        <\/a>\n\n        <!-- Card 7: Percentage Yield -->\n        <a class=\"ols-aqa312-card ols-aqa312-card--available\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-2-amount-of-substance\/percentage-yield\/\">\n          <div class=\"ols-aqa312-card-img-wrap\">\n            <div class=\"ols-aqa312-visual ols-aqa312-visual--seven\">\n              <div class=\"ols-aqa312-visual-panel\">\n                <div class=\"ols-aqa312-visual-kicker\">Reaction yield<\/div>\n                <div class=\"ols-aqa312-visual-main\">Percentage<br>Yield<\/div>\n                <div class=\"ols-aqa312-config-line\" aria-hidden=\"true\"><span>% yield<\/span><\/div>\n              <\/div>\n            <\/div>\n            <div class=\"ols-aqa312-card-num\">7<\/div>\n            <span class=\"ols-aqa312-card-status ols-aqa312-card-status--available\">Available<\/span>\n          <\/div>\n          <div class=\"ols-aqa312-card-body\">\n            <p class=\"ols-aqa312-card-title\">Percentage Yield<\/p>\n            <p class=\"ols-aqa312-card-desc\">Percentage yield calculations from theoretical and actual yield in chemical reactions.<\/p>\n            <span class=\"ols-aqa312-card-cta\">\n              Start revising\n              <svg viewBox=\"0 0 16 16\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><path d=\"M3 8h10M9 4l4 4-4 4\"><\/path><\/svg>\n            <\/span>\n          <\/div>\n        <\/a>\n\n        <!-- Card 8: Atom Economy -->\n        <a class=\"ols-aqa312-card ols-aqa312-card--available\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/aqa\/3-1-2-amount-of-substance\/atom-economy\/\">\n          <div class=\"ols-aqa312-card-img-wrap\">\n            <div class=\"ols-aqa312-visual ols-aqa312-visual--eight\">\n              <div class=\"ols-aqa312-visual-panel\">\n                <div class=\"ols-aqa312-visual-kicker\">Efficient synthesis<\/div>\n                <div class=\"ols-aqa312-visual-main\">Atom<br>Economy<\/div>\n                <div class=\"ols-aqa312-config-line\" aria-hidden=\"true\"><span>% atom<\/span><\/div>\n              <\/div>\n            <\/div>\n            <div class=\"ols-aqa312-card-num\">8<\/div>\n            <span class=\"ols-aqa312-card-status ols-aqa312-card-status--available\">Available<\/span>\n          <\/div>\n          <div class=\"ols-aqa312-card-body\">\n            <p class=\"ols-aqa312-card-title\">Atom Economy<\/p>\n            <p class=\"ols-aqa312-card-desc\">Percentage atom economy and the economic, ethical and environmental value of efficient reactions.<\/p>\n            <span class=\"ols-aqa312-card-cta\">\n              Start revising\n              <svg viewBox=\"0 0 16 16\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><path d=\"M3 8h10M9 4l4 4-4 4\"><\/path><\/svg>\n            <\/span>\n          <\/div>\n        <\/a>\n      <\/div>\n    <\/div>\n  <\/section>\n\n  <!-- SPECIFICATION -->\n  <section class=\"ols-aqa312-spec-section\">\n    <div class=\"ols-aqa312-container\">\n\n      <!-- DESKTOP SPECIFICATION -->\n      <div class=\"ols-aqa312-spec-desktop\">\n        <div class=\"ols-aqa312-spec-wrap\">\n          <div class=\"ols-aqa312-spec-pill\">Specification Coverage<\/div>\n          <h2 class=\"ols-aqa312-spec-heading\">3.1.2 Amount of Substance &#8211; AQA A Level Chemistry<\/h2>\n          <p class=\"ols-aqa312-spec-intro-text\">The following AQA specification points outline the knowledge and skills students are expected to demonstrate for Amount of Substance.<\/p>\n\n          <h3 class=\"ols-aqa312-spec-group-title\">3.1.2 Amount of Substance<\/h3>\n          <div class=\"ols-aqa312-spec-rows\">\n<div class=\"ols-aqa312-spec-row ols-aqa312-spec-row--light\"><div class=\"ols-aqa312-spec-code\">3.1.2.1<\/div><div class=\"ols-aqa312-spec-text\"><strong>Relative atomic mass and relative molecular mass<\/strong><br>Relative atomic mass and relative molecular mass in terms of <sup>12<\/sup>C.<br>The term relative formula mass will be used for ionic compounds.<br>Students should be able to:<div class=\"ols-aqa312-spec-sub-list\"><div class=\"ols-aqa312-spec-sub-row\"><div class=\"ols-aqa312-spec-sub-code\">1<\/div><div class=\"ols-aqa312-spec-sub-text\">define relative atomic mass (A<sub>r<\/sub>)<\/div><\/div><div class=\"ols-aqa312-spec-sub-row\"><div class=\"ols-aqa312-spec-sub-code\">2<\/div><div class=\"ols-aqa312-spec-sub-text\">define relative molecular mass (M<sub>r<\/sub>).<\/div><\/div><\/div><\/div><\/div>\n<div class=\"ols-aqa312-spec-row ols-aqa312-spec-row--mid\"><div class=\"ols-aqa312-spec-code ols-aqa312-spec-code--mid\">3.1.2.2<\/div><div class=\"ols-aqa312-spec-text\"><strong>The mole and the Avogadro constant<\/strong><br>The Avogadro constant as the number of particles in a mole.<br>The mole as applied to electrons, atoms, molecules, ions, formulas and equations.<br>The concentration of a substance in solution, measured in mol dm<sup>-3<\/sup>.<br>Students should be able to carry out calculations:<div class=\"ols-aqa312-spec-sub-list\"><div class=\"ols-aqa312-spec-sub-row\"><div class=\"ols-aqa312-spec-sub-code\">1<\/div><div class=\"ols-aqa312-spec-sub-text\">using the Avogadro constant<\/div><\/div><div class=\"ols-aqa312-spec-sub-row\"><div class=\"ols-aqa312-spec-sub-code\">2<\/div><div class=\"ols-aqa312-spec-sub-text\">using mass of substance, M<sub>r<\/sub>, and amount in moles<\/div><\/div><div class=\"ols-aqa312-spec-sub-row\"><div class=\"ols-aqa312-spec-sub-code\">3<\/div><div class=\"ols-aqa312-spec-sub-text\">using concentration, volume and amount of substance in a solution.<\/div><\/div><\/div><br>Students will not be expected to recall the value of the Avogadro constant.<\/div><\/div>\n<div class=\"ols-aqa312-spec-row ols-aqa312-spec-row--light\"><div class=\"ols-aqa312-spec-code\">3.1.2.3<\/div><div class=\"ols-aqa312-spec-text\"><strong>The ideal gas equation<\/strong><br>The ideal gas equation pV = nRT with the variables in SI units.<br>Students should be able to:<div class=\"ols-aqa312-spec-sub-list\"><div class=\"ols-aqa312-spec-sub-row\"><div class=\"ols-aqa312-spec-sub-code\">1<\/div><div class=\"ols-aqa312-spec-sub-text\">use the equation in calculations.<\/div><\/div><\/div><br>Students will not be expected to recall the value of the gas constant, R.<\/div><\/div>\n<div class=\"ols-aqa312-spec-row ols-aqa312-spec-row--light\"><div class=\"ols-aqa312-spec-code\">3.1.2.4<\/div><div class=\"ols-aqa312-spec-text\"><strong>Empirical and molecular formula<\/strong><br>Empirical formula is the simplest whole number ratio of atoms of each element in a compound.<br>Molecular formula is the actual number of atoms of each element in a compound.<br>The relationship between empirical formula and molecular formula.<br>Students should be able to:<div class=\"ols-aqa312-spec-sub-list\"><div class=\"ols-aqa312-spec-sub-row\"><div class=\"ols-aqa312-spec-sub-code\">1<\/div><div class=\"ols-aqa312-spec-sub-text\">calculate empirical formula from data giving composition by mass or percentage by mass<\/div><\/div><div class=\"ols-aqa312-spec-sub-row\"><div class=\"ols-aqa312-spec-sub-code\">2<\/div><div class=\"ols-aqa312-spec-sub-text\">calculate molecular formula from the empirical formula and relative molecular mass.<\/div><\/div><\/div><\/div><\/div>\n<div class=\"ols-aqa312-spec-row ols-aqa312-spec-row--mid\"><div class=\"ols-aqa312-spec-code ols-aqa312-spec-code--mid\">3.1.2.5<\/div><div class=\"ols-aqa312-spec-text\"><strong>Balanced equations and associated calculations<\/strong><br>Equations (full and ionic).<br>Percentage atom economy is: molecular mass of desired product \/ sum of molecular masses of all reactants x 100<br>Economic, ethical and environmental advantages for society and for industry of developing chemical processes with a high atom economy.<br>Students should be able to:<div class=\"ols-aqa312-spec-sub-list\"><div class=\"ols-aqa312-spec-sub-row\"><div class=\"ols-aqa312-spec-sub-code\">1<\/div><div class=\"ols-aqa312-spec-sub-text\">write balanced equations for reactions studied<\/div><\/div><div class=\"ols-aqa312-spec-sub-row\"><div class=\"ols-aqa312-spec-sub-code\">2<\/div><div class=\"ols-aqa312-spec-sub-text\">balance equations for unfamiliar reactions when reactants and products are specified.<\/div><\/div><\/div><br>Students should be able to use balanced equations to calculate:<div class=\"ols-aqa312-spec-sub-list\"><div class=\"ols-aqa312-spec-sub-row\"><div class=\"ols-aqa312-spec-sub-code\">1<\/div><div class=\"ols-aqa312-spec-sub-text\">masses<\/div><\/div><div class=\"ols-aqa312-spec-sub-row\"><div class=\"ols-aqa312-spec-sub-code\">2<\/div><div class=\"ols-aqa312-spec-sub-text\">volumes of gases<\/div><\/div><div class=\"ols-aqa312-spec-sub-row\"><div class=\"ols-aqa312-spec-sub-code\">3<\/div><div class=\"ols-aqa312-spec-sub-text\">percentage yields<\/div><\/div><div class=\"ols-aqa312-spec-sub-row\"><div class=\"ols-aqa312-spec-sub-code\">4<\/div><div class=\"ols-aqa312-spec-sub-text\">percentage atom economies<\/div><\/div><div class=\"ols-aqa312-spec-sub-row\"><div class=\"ols-aqa312-spec-sub-code\">5<\/div><div class=\"ols-aqa312-spec-sub-text\">concentrations and volumes for reactions in solutions.<\/div><\/div><\/div><\/div><\/div>\n          <\/div>\n        <\/div>\n      <\/div>\n\n      <!-- MOBILE SPECIFICATION -->\n      <div class=\"ols-aqa312-spec-mobile\">\n        <div class=\"ols-aqa312-spec-wrap\">\n          <div class=\"ols-aqa312-spec-pill\">Specification Coverage<\/div>\n          <h2 class=\"ols-aqa312-spec-heading\">3.1.2 Amount of Substance &#8211; AQA A Level Chemistry<\/h2>\n          <p class=\"ols-aqa312-spec-intro-text\">The following AQA specification points outline the knowledge and skills students are expected to demonstrate for Amount of Substance.<\/p>\n\n          <h3 class=\"ols-aqa312-spec-group-title\">3.1.2 Amount of Substance<\/h3>\n          <div class=\"ols-aqa312-spec-mob-rows\">\n<div class=\"ols-aqa312-spec-mob-row ols-aqa312-spec-mob-row--light\"><div class=\"ols-aqa312-spec-mob-code\">3.1.2.1<\/div><div class=\"ols-aqa312-spec-mob-text\"><strong>Relative atomic mass and relative molecular mass<\/strong><br>Relative atomic mass and relative molecular mass in terms of <sup>12<\/sup>C.<br>The term relative formula mass will be used for ionic compounds.<br>Students should be able to:<div class=\"ols-aqa312-spec-mob-sub-list\"><div class=\"ols-aqa312-spec-mob-sub-row\"><div class=\"ols-aqa312-spec-mob-sub-code\">1<\/div><div class=\"ols-aqa312-spec-mob-sub-text\">define relative atomic mass (A<sub>r<\/sub>)<\/div><\/div><div class=\"ols-aqa312-spec-mob-sub-row\"><div class=\"ols-aqa312-spec-mob-sub-code\">2<\/div><div class=\"ols-aqa312-spec-mob-sub-text\">define relative molecular mass (M<sub>r<\/sub>).<\/div><\/div><\/div><\/div><\/div>\n<div class=\"ols-aqa312-spec-mob-row ols-aqa312-spec-mob-row--mid\"><div class=\"ols-aqa312-spec-mob-code ols-aqa312-spec-mob-code--mid\">3.1.2.2<\/div><div class=\"ols-aqa312-spec-mob-text\"><strong>The mole and the Avogadro constant<\/strong><br>The Avogadro constant as the number of particles in a mole.<br>The mole as applied to electrons, atoms, molecules, ions, formulas and equations.<br>The concentration of a substance in solution, measured in mol dm<sup>-3<\/sup>.<br>Students should be able to carry out calculations:<div class=\"ols-aqa312-spec-mob-sub-list\"><div class=\"ols-aqa312-spec-mob-sub-row\"><div class=\"ols-aqa312-spec-mob-sub-code\">1<\/div><div class=\"ols-aqa312-spec-mob-sub-text\">using the Avogadro constant<\/div><\/div><div class=\"ols-aqa312-spec-mob-sub-row\"><div class=\"ols-aqa312-spec-mob-sub-code\">2<\/div><div class=\"ols-aqa312-spec-mob-sub-text\">using mass of substance, M<sub>r<\/sub>, and amount in moles<\/div><\/div><div class=\"ols-aqa312-spec-mob-sub-row\"><div class=\"ols-aqa312-spec-mob-sub-code\">3<\/div><div class=\"ols-aqa312-spec-mob-sub-text\">using concentration, volume and amount of substance in a solution.<\/div><\/div><\/div><br>Students will not be expected to recall the value of the Avogadro constant.<\/div><\/div>\n<div class=\"ols-aqa312-spec-mob-row ols-aqa312-spec-mob-row--light\"><div class=\"ols-aqa312-spec-mob-code\">3.1.2.3<\/div><div class=\"ols-aqa312-spec-mob-text\"><strong>The ideal gas equation<\/strong><br>The ideal gas equation pV = nRT with the variables in SI units.<br>Students should be able to:<div class=\"ols-aqa312-spec-mob-sub-list\"><div class=\"ols-aqa312-spec-mob-sub-row\"><div class=\"ols-aqa312-spec-mob-sub-code\">1<\/div><div class=\"ols-aqa312-spec-mob-sub-text\">use the equation in calculations.<\/div><\/div><\/div><br>Students will not be expected to recall the value of the gas constant, R.<\/div><\/div>\n<div class=\"ols-aqa312-spec-mob-row ols-aqa312-spec-mob-row--light\"><div class=\"ols-aqa312-spec-mob-code\">3.1.2.4<\/div><div class=\"ols-aqa312-spec-mob-text\"><strong>Empirical and molecular formula<\/strong><br>Empirical formula is the simplest whole number ratio of atoms of each element in a compound.<br>Molecular formula is the actual number of atoms of each element in a compound.<br>The relationship between empirical formula and molecular formula.<br>Students should be able to:<div class=\"ols-aqa312-spec-mob-sub-list\"><div class=\"ols-aqa312-spec-mob-sub-row\"><div class=\"ols-aqa312-spec-mob-sub-code\">1<\/div><div class=\"ols-aqa312-spec-mob-sub-text\">calculate empirical formula from data giving composition by mass or percentage by mass<\/div><\/div><div class=\"ols-aqa312-spec-mob-sub-row\"><div class=\"ols-aqa312-spec-mob-sub-code\">2<\/div><div class=\"ols-aqa312-spec-mob-sub-text\">calculate molecular formula from the empirical formula and relative molecular mass.<\/div><\/div><\/div><\/div><\/div>\n<div class=\"ols-aqa312-spec-mob-row ols-aqa312-spec-mob-row--mid\"><div class=\"ols-aqa312-spec-mob-code ols-aqa312-spec-mob-code--mid\">3.1.2.5<\/div><div class=\"ols-aqa312-spec-mob-text\"><strong>Balanced equations and associated calculations<\/strong><br>Equations (full and ionic).<br>Percentage atom economy is: molecular mass of desired product \/ sum of molecular masses of all reactants x 100<br>Economic, ethical and environmental advantages for society and for industry of developing chemical processes with a high atom economy.<br>Students should be able to:<div class=\"ols-aqa312-spec-mob-sub-list\"><div class=\"ols-aqa312-spec-mob-sub-row\"><div class=\"ols-aqa312-spec-mob-sub-code\">1<\/div><div class=\"ols-aqa312-spec-mob-sub-text\">write balanced equations for reactions studied<\/div><\/div><div class=\"ols-aqa312-spec-mob-sub-row\"><div class=\"ols-aqa312-spec-mob-sub-code\">2<\/div><div class=\"ols-aqa312-spec-mob-sub-text\">balance equations for unfamiliar reactions when reactants and products are specified.<\/div><\/div><\/div><br>Students should be able to use balanced equations to calculate:<div class=\"ols-aqa312-spec-mob-sub-list\"><div class=\"ols-aqa312-spec-mob-sub-row\"><div class=\"ols-aqa312-spec-mob-sub-code\">1<\/div><div class=\"ols-aqa312-spec-mob-sub-text\">masses<\/div><\/div><div class=\"ols-aqa312-spec-mob-sub-row\"><div class=\"ols-aqa312-spec-mob-sub-code\">2<\/div><div class=\"ols-aqa312-spec-mob-sub-text\">volumes of gases<\/div><\/div><div class=\"ols-aqa312-spec-mob-sub-row\"><div class=\"ols-aqa312-spec-mob-sub-code\">3<\/div><div class=\"ols-aqa312-spec-mob-sub-text\">percentage yields<\/div><\/div><div class=\"ols-aqa312-spec-mob-sub-row\"><div class=\"ols-aqa312-spec-mob-sub-code\">4<\/div><div class=\"ols-aqa312-spec-mob-sub-text\">percentage atom economies<\/div><\/div><div class=\"ols-aqa312-spec-mob-sub-row\"><div class=\"ols-aqa312-spec-mob-sub-code\">5<\/div><div class=\"ols-aqa312-spec-mob-sub-text\">concentrations and volumes for reactions in solutions.<\/div><\/div><\/div><\/div><\/div>\n          <\/div>\n        <\/div>\n      <\/div>\n\n    <\/div>\n  <\/section>\n\n<script type=\"application\/ld+json\">\n{\n  \"@context\": \"https:\/\/schema.org\",\n  \"@graph\": [\n    {\n      \"@type\": \"WebPage\",\n      \"@id\": 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This topic covers relative masses, the mole, Avogadro constant, empirical and molecular formulae, balanced equations, reacting masses, solution concentrations, titration calculations, gas volumes, percentage yield and atom economy. [&hellip;]<\/p>\n","protected":false},"author":12,"featured_media":0,"parent":5210,"menu_order":1,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-5272","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-json\/wp\/v2\/pages\/5272","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-json\/wp\/v2\/users\/12"}],"replies":[{"embeddable":true,"href":"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-json\/wp\/v2\/comments?post=5272"}],"version-history":[{"count":0,"href":"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-json\/wp\/v2\/pages\/5272\/revisions"}],"up":[{"embeddable":true,"href":"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-json\/wp\/v2\/pages\/5210"}],"wp:attachment":[{"href":"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-json\/wp\/v2\/media?parent=5272"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}