{"id":4000,"date":"2026-05-21T07:03:08","date_gmt":"2026-05-21T06:03:08","guid":{"rendered":"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-1-formulae-equations-and-amount-of-substance\/equations-and-reaction-types\/"},"modified":"2026-05-26T06:04:41","modified_gmt":"2026-05-26T05:04:41","slug":"equations-and-reaction-types","status":"publish","type":"page","link":"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-1-formulae-equations-and-amount-of-substance\/equations-and-reaction-types\/","title":{"rendered":"Equations and Reaction Types"},"content":{"rendered":"\n<section class=\"ols-revision-page ols-equations-reaction-types-landing-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      --soft-orange: 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ease;\n    }\n\n    .ols-ert-card:hover .ols-ert-meta {\n      background: var(--blue);\n      transform: translateX(4px);\n    }\n\n    .ols-related-grid {\n      display: grid;\n      grid-template-columns: repeat(3, minmax(0, 1fr));\n      gap: 16px;\n      margin-top: 18px;\n    }\n\n    .ols-related-item {\n      border: 1px solid var(--border);\n      border-radius: 18px;\n      padding: 18px;\n      background: #ffffff;\n      color: var(--navy);\n      text-decoration: none;\n      font-weight: 600;\n      line-height: 1.5;\n      transition: transform 0.2s ease, box-shadow 0.2s ease, color 0.2s ease;\n    }\n\n    .ols-related-item:hover {\n      transform: translateY(-2px);\n      box-shadow: 0 10px 22px rgba(28, 36, 75, 0.08);\n      color: var(--blue);\n    }\n\n    .ols-attribution-card {\n      background: linear-gradient(135deg, #ffffff 0%, #f8fbff 100%);\n    }\n\n    .ols-attribution-card p {\n      margin: 0;\n      font-size: 14px;\n      color: var(--grey-text);\n    }\n\n    @media (max-width: 1050px) {\n      .ols-revision-layout { grid-template-columns: 1fr; }\n.ols-main { max-width: none; }\n      .ols-related-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }\n    }\n\n    @media (max-width: 760px) {\n      .ols-revision-layout { padding: 14px 12px 44px; }\n      .ols-title-card, .ols-note-card, .ols-related-card, .ols-attribution-card { padding: 24px 18px; border-radius: 22px; }\n      .ols-note-title { align-items: flex-start; }\n.ols-author { align-items: flex-start; padding: 22px 18px; border-radius: 22px; }\n      .ols-author-avatar-img { width: 72px; height: 72px; }\n      .ols-author-title { font-size: 24px; }\n      .ols-author-description { font-size: 15px; }\n      .ols-ert-card { min-height: 255px; }\n    }\n  <\/style>\n\n      <aside class=\"ols-sidebar\">\r\n  <div class=\"ols-sidebar-header\">\r\n    <h3>Revision Notes<\/h3>\r\n    <p>A Level Chemistry<\/p>\r\n  <\/div>\r\n\r\n  <div class=\"ols-topic-group\">\r\n    <h4>Topic 1 Formulae, Equations and 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\/edexcel-international\/topic-1-formulae-equations-and-amount-of-substance\/atoms-elements-and-molecules\/\">Atoms, Elements and Molecules<\/a>\r\n      <\/li>\r\n\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-1-formulae-equations-and-amount-of-substance\/equations-and-reaction-types\/\">Equations and Reaction Types<\/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\/edexcel-international\/topic-1-formulae-equations-and-amount-of-substance\/equations-and-reaction-types\/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\/edexcel-international\/topic-1-formulae-equations-and-amount-of-substance\/equations-and-reaction-types\/typical-reactions-of-acids\/\">Typical Reactions of Acids<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-1-formulae-equations-and-amount-of-substance\/equations-and-reaction-types\/ionic-equations\/\">Ionic Equations<\/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\/edexcel-international\/topic-1-formulae-equations-and-amount-of-substance\/mole-calculations\/\">Mole 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\/edexcel-international\/topic-1-formulae-equations-and-amount-of-substance\/mole-calculations\/comparing-masses-of-substances\/\">Comparing Masses of Substances<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-1-formulae-equations-and-amount-of-substance\/mole-calculations\/calculations-involving-moles\/\">Calculations involving Moles<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-1-formulae-equations-and-amount-of-substance\/mole-calculations\/calculations-using-reacting-masses\/\">Calculations using Reacting Masses<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-1-formulae-equations-and-amount-of-substance\/mole-calculations\/the-yield-of-a-reaction\/\">The Yield of a Reaction<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-1-formulae-equations-and-amount-of-substance\/mole-calculations\/atom-economy\/\">Atom Economy<\/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\/edexcel-international\/topic-1-formulae-equations-and-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\/edexcel-international\/topic-1-formulae-equations-and-amount-of-substance\/empirical-and-molecular-formulae\/empirical-formulae\/\">Empirical Formulae<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-1-formulae-equations-and-amount-of-substance\/empirical-and-molecular-formulae\/molecular-formulae\/\">Molecular Formulae<\/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\/edexcel-international\/topic-1-formulae-equations-and-amount-of-substance\/calculations-with-solutions-and-gases\/\">Calculations with Solutions and Gases<\/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\/edexcel-international\/topic-1-formulae-equations-and-amount-of-substance\/calculations-with-solutions-and-gases\/molar-volume-calculations\/\">Molar Volume Calculations<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-1-formulae-equations-and-amount-of-substance\/calculations-with-solutions-and-gases\/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\/edexcel-international\/topic-1-formulae-equations-and-amount-of-substance\/calculations-with-solutions-and-gases\/concentrations-in-ppm\/\">Concentrations in PPM<\/a>\r\n          <\/li>\r\n        <\/ul>\r\n      <\/li>\r\n    <\/ul>\r\n  <\/div>\r\n\r\n  <div 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\/\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-1-formulae-equations-and-amount-of-substance\/\">Topic 1 Formulae, Equations and Amount of Substance<\/a> \/\n        <span>Equations and Reaction Types<\/span>\n      <\/nav>\n\n      <header class=\"ols-title-card\">\n        <h1>Equations and Reaction Types<\/h1>\n        <p class=\"ols-page-intro\">Use this landing page to move quickly between the key equations and reaction types revision pages for Topic 1. Each card links to a focused page covering chemical equations, acid reactions and ionic equations.<\/p>\n\n        <div class=\"ols-badges\">\n          <div class=\"ols-badge\">Exam board: Edexcel International<\/div>\n          <div class=\"ols-badge\">Topic 1: Formulae, Equations and Amount of Substance<\/div>\n          <div class=\"ols-badge\">Level: A Level Chemistry<\/div>\n        <\/div>\n\n        <div class=\"ols-author\">\n          <img decoding=\"async\" class=\"ols-author-avatar-img\" src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/05\/Author-Profile.jpeg\" alt=\"Dr. Mohammed Al-Fatah\">\n\n          <div class=\"ols-author-content\">\n            <h2 class=\"ols-author-title\">Written by:<br><span>Dr. Mohammed Al-Fatah<\/span><\/h2>\n            <p class=\"ols-author-description\">Chemistry specialist revision notes for A Level Chemistry.<\/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\"><\/path>\n              <\/svg>\n              View LinkedIn Profile\n            <\/a>\n          <\/div>\n        <\/div>\n      <\/header>\n\n      <article class=\"ols-note-card soft\">\n        <div class=\"ols-note-title\">\n          <div class=\"ols-note-icon\">1<\/div>\n          <h2>Choose an Equations and Reaction Types Page<\/h2>\n        <\/div>\n\n        <p>Equations and reaction types link chemical formulae to what actually happens during a chemical change. These pages build from writing balanced chemical equations through to recognising acid reactions and writing ionic equations.<\/p>\n\n        <div class=\"ols-key-box\">\n          <p><strong>Key idea:<\/strong> A balanced chemical equation shows the correct formulae of the reactants and products, while the reaction type helps you predict what products are formed.<\/p>\n        <\/div>\n\n        <div class=\"ols-ert-grid\">\n          <a class=\"ols-ert-card\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-1-formulae-equations-and-amount-of-substance\/equations-and-reaction-types\/writing-chemical-equations\/\">\n            <div class=\"ols-ert-visual\">\n              <div class=\"ols-ert-icon ols-ert-equation\" aria-hidden=\"true\">\n                <span class=\"ols-ert-box b1\">A<\/span>\n                <span class=\"ols-ert-label-mini\">+<\/span>\n                <span class=\"ols-ert-box b2\">B<\/span>\n                <span class=\"ols-ert-arrow\"><\/span>\n                <span class=\"ols-ert-box b3\">AB<\/span>\n              <\/div>\n            <\/div>\n            <h3>Writing Chemical Equations<\/h3>\n            <p>Revise word equations, symbol equations, balancing equations and the correct use of state symbols.<\/p>\n            <span class=\"ols-ert-meta\">Open revision page<\/span>\n          <\/a>\n\n          <a class=\"ols-ert-card\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-1-formulae-equations-and-amount-of-substance\/equations-and-reaction-types\/typical-reactions-of-acids\/\">\n            <div class=\"ols-ert-visual\">\n              <div class=\"ols-ert-icon ols-ert-acid\" aria-hidden=\"true\">\n                <span class=\"ols-ert-label-mini\">acid<\/span>\n                <span class=\"ols-ert-box neck\"><\/span>\n                <span class=\"ols-ert-box flask\"><\/span>\n                <span class=\"ols-ert-bubble c1\"><\/span>\n                <span class=\"ols-ert-bubble c2\"><\/span>\n                <span class=\"ols-ert-bubble c3\"><\/span>\n              <\/div>\n            <\/div>\n            <h3>Typical Reactions of Acids<\/h3>\n            <p>Learn the common products formed when acids react with metals, bases, alkalis and carbonates.<\/p>\n            <span class=\"ols-ert-meta\">Open revision page<\/span>\n          <\/a>\n          <a class=\"ols-ert-card\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-1-formulae-equations-and-amount-of-substance\/equations-and-reaction-types\/ionic-equations\/\">\n            <div class=\"ols-ert-visual\">\n              <div class=\"ols-ert-icon ols-ert-ionic\" aria-hidden=\"true\">\n                <span class=\"ols-ert-ion i1\">Na\u207a<\/span>\n                <span class=\"ols-ert-ion i2\">Cl\u207b<\/span>\n                <span class=\"ols-ert-arrow\"><\/span>\n                <span class=\"ols-ert-ion i3\">NaCl<\/span>\n                <span class=\"ols-ert-label-mini\">ions<\/span>\n              <\/div>\n            <\/div>\n            <h3>Ionic Equations<\/h3>\n            <p>Learn how ionic equations show only the reacting ions and remove spectator ions from chemical equations.<\/p>\n            <span class=\"ols-ert-meta\">Open revision page<\/span>\n          <\/a>\n        <\/div>\n      <\/article>\n\n      <article class=\"ols-note-card purple\">\n        <div class=\"ols-note-title\">\n          <div class=\"ols-note-icon\">\u2713<\/div>\n          <h2>How to Use These Pages<\/h2>\n        <\/div>\n\n        <p>Start with writing chemical equations so that your formulae, coefficients and state symbols are accurate. Then move to typical acid reactions, because these product patterns appear frequently in early quantitative chemistry. Finally, use the ionic equations page to practise removing spectator ions and showing the ions that actually react.<\/p>\n\n        <div class=\"ols-key-box\">\n          <p><strong>Exam focus:<\/strong> When writing equations, check formulae before balancing. Changing a subscript changes the substance, but changing a coefficient changes the number of particles or formula units.<\/p>\n        <\/div>\n      <\/article>\n\n      <section class=\"ols-related-card\">\n        <h2>Related Topic 1 Pages<\/h2>\n        <p>Use these pages to connect equations and reaction types with formulae, relative formula mass, empirical formulae and amount of substance calculations.<\/p>\n\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-1-formulae-equations-and-amount-of-substance\/atoms-elements-and-molecules\/\">Atoms, Elements and Molecules<\/a>\n          <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-1-formulae-equations-and-amount-of-substance\/equations-and-reaction-types\/writing-chemical-equations\/\">Writing Chemical Equations<\/a>\n          <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-1-formulae-equations-and-amount-of-substance\/equations-and-reaction-types\/typical-reactions-of-acids\/\">Typical Reactions of Acids<\/a>\n          <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-1-formulae-equations-and-amount-of-substance\/equations-and-reaction-types\/ionic-equations\/\">Ionic Equations<\/a>\n          <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-2-atomic-structure-and-the-periodic-table\/\">Next Topic: Atomic Structure &amp; The Periodic Table<\/a>\n        <\/div>\n      <\/section>\n\n      <section class=\"ols-attribution-card\">\n        <p><strong>Copyright notice:<\/strong> This revision page, including its written explanations, layout and teaching sequence, is produced for Online Learning System by Dr. Mohammed Al-Fatah. It is intended for student revision and may not be copied, redistributed or republished without permission.<\/p>\n      <\/section>\n\n      <script type=\"application\/ld+json\">\n      {\n        \"@context\": \"https:\/\/schema.org\",\n        \"@graph\": [\n          {\n            \"@type\": \"WebPage\",\n            \"@id\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-1-formulae-equations-and-amount-of-substance\/equations-and-reaction-types\/#webpage\",\n            \"url\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-1-formulae-equations-and-amount-of-substance\/equations-and-reaction-types\/\",\n            \"name\": \"Equations and Reaction Types Revision Notes\",\n            \"description\": \"A Level Chemistry landing page for equations and reaction types, including writing chemical equations, typical reactions of acids and ionic equations.\",\n            \"inLanguage\": \"en-GB\",\n            \"isPartOf\": {\n              \"@type\": \"WebSite\",\n              \"@id\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/#website\",\n              \"name\": \"Online Learning System\",\n              \"url\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/\"\n            },\n            \"about\": [\n              {\n                \"@type\": \"Thing\",\n                \"name\": \"Chemical equations\"\n              },\n              {\n                \"@type\": \"Thing\",\n                \"name\": \"Acid reactions\"\n              },\n              {\n                \"@type\": \"Thing\",\n                \"name\": \"Ionic equations\"\n              }\n            ],\n            \"author\": {\n              \"@type\": \"Person\",\n              \"name\": \"Dr. Mohammed Al-Fatah\",\n              \"url\": \"https:\/\/www.linkedin.com\/in\/doctormohammedfatah\/\"\n            },\n            \"publisher\": {\n              \"@type\": \"Organization\",\n              \"name\": \"Online Learning System\",\n              \"url\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/\"\n            }\n          },\n          {\n            \"@type\": \"BreadcrumbList\",\n            \"@id\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-1-formulae-equations-and-amount-of-substance\/equations-and-reaction-types\/#breadcrumb\",\n            \"itemListElement\": [\n              {\n                \"@type\": \"ListItem\",\n                \"position\": 1,\n                \"name\": \"Revision Notes\",\n                \"item\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/\"\n              },\n              {\n                \"@type\": \"ListItem\",\n                \"position\": 2,\n                \"name\": \"A Level Chemistry\",\n                \"item\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/\"\n              },\n              {\n                \"@type\": \"ListItem\",\n                \"position\": 3,\n                \"name\": \"Edexcel International\",\n                \"item\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/\"\n              },\n              {\n                \"@type\": \"ListItem\",\n                \"position\": 4,\n                \"name\": \"Topic 1 Formulae, Equations and Amount of Substance\",\n                \"item\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-1-formulae-equations-and-amount-of-substance\/\"\n              },\n              {\n                \"@type\": \"ListItem\",\n                \"position\": 5,\n                \"name\": \"Equations and Reaction Types\",\n                \"item\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-1-formulae-equations-and-amount-of-substance\/equations-and-reaction-types\/\"\n              }\n            ]\n          }\n        ]\n      }\n      <\/script>\n    <\/main>\n<\/section>\n","protected":false},"excerpt":{"rendered":"<p>Revision Notes \/ A Level Chemistry \/ Edexcel International \/ Topic 1 Formulae, Equations and Amount of Substance \/ Equations and Reaction Types Equations and Reaction Types Use this landing page to move quickly between the key equations and reaction types revision pages for Topic 1. 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