{"id":8052,"date":"2026-09-15T08:23:36","date_gmt":"2026-09-15T07:23:36","guid":{"rendered":"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-2-compounds-formulae-and-equations\/equations-and-reaction-types\/"},"modified":"2026-09-19T19:39:08","modified_gmt":"2026-09-19T18:39:08","slug":"equations-and-reaction-types","status":"publish","type":"page","link":"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-2-compounds-formulae-and-equations\/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: #fff7ed;\n      --gold: #c9973a;\n      --grey-text: #667085;\n      --body-text: #1f2937;\n      --border: rgba(28, 36, 75, 0.14);\n      --shadow: 0 18px 45px rgba(28, 36, 75, 0.10);\n      --inner-shadow: 0 10px 26px rgba(28, 36, 75, 0.08);\n      font-family: Poppins, Arial, sans-serif;\n      color: var(--navy);\n      background: #ffffff;\n    }\n\n    .ols-revision-page * { box-sizing: border-box; }\n\n    .ols-revision-layout {\n      display: block;\n      max-width: 1450px;\n      margin: 0 auto;\n      padding: 24px 20px 60px;\n    }\n.ols-breadcrumbs {\n      display: flex;\n      flex-wrap: wrap;\n      gap: 8px;\n      margin: 10px 0 22px;\n      font-size: 15px;\n      color: var(--grey-text);\n    }\n\n    .ols-breadcrumbs a,\n    .ols-breadcrumbs span {\n      color: var(--grey-text);\n      text-decoration: none;\n      font-weight: 600;\n    }\n\n    .ols-breadcrumbs a:hover {\n      color: var(--blue);\n      text-decoration: underline;\n      text-underline-offset: 3px;\n    }\n\n    .ols-title-card,\n    .ols-note-card,\n    .ols-related-card,\n    .ols-attribution-card {\n      background: #ffffff;\n      border: 1px solid var(--border);\n      border-radius: 28px;\n      box-shadow: var(--shadow);\n      padding: 34px;\n      margin-bottom: 24px;\n      overflow: hidden;\n    }\n\n    .ols-title-card {\n      background: linear-gradient(135deg, #ffffff 0%, #f8fbff 100%);\n    }\n\n    .ols-title-card h1 {\n      margin: 0 0 18px;\n      font-size: clamp(36px, 5vw, 58px);\n      line-height: 1.08;\n      font-weight: 800;\n      letter-spacing: -0.04em;\n      color: #111827;\n    }\n\n    .ols-page-intro {\n      font-size: 19px;\n      line-height: 1.7;\n      font-weight: 300;\n      color: var(--body-text);\n      margin: 0 0 22px;\n    }\n\n    .ols-badges {\n      display: flex;\n      flex-direction: column;\n      align-items: flex-start;\n      gap: 12px;\n      margin-bottom: 22px;\n    }\n\n    .ols-badge {\n      display: inline-flex;\n      align-items: center;\n      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box-shadow: 0 20px 42px rgba(28,36,75,0.22), 0 0 0 1px rgba(28,36,75,0.10);\n    }\n\n    .ols-author-content { min-width: 0; }\n\n    .ols-author-title {\n      margin: 0 0 4px;\n      font-size: clamp(24px,3vw,34px);\n      line-height: 1.15;\n      font-weight: 700;\n      color: var(--navy);\n      letter-spacing: -0.03em;\n    }\n\n    .ols-author-description {\n      margin: 0;\n      font-size: 17px;\n      line-height: 1.7;\n      font-weight: 300;\n      color: var(--grey-text);\n    }\n\n    .ols-linkedin-pill {\n      display: inline-flex;\n      align-items: center;\n      justify-content: center;\n      gap: 10px;\n      margin-top: 16px;\n      padding: 11px 18px;\n      border-radius: 999px;\n      background: linear-gradient(135deg,#0A66C2,#004182);\n      color: #ffffff;\n      text-decoration: none;\n      font-size: 14px;\n      line-height: 1;\n      font-weight: 700;\n      letter-spacing: 0.01em;\n      box-shadow: 0 10px 22px rgba(10,102,194,0.24);\n      position: relative;\n      overflow: hidden;\n      transition: transform 0.22s ease, box-shadow 0.22s ease;\n    }\n\n    .ols-linkedin-pill::before {\n      content: \"\";\n      position: absolute;\n      top: 0;\n      left: -120%;\n      width: 100%;\n      height: 100%;\n      background: linear-gradient(120deg, rgba(255,255,255,0) 0%, rgba(255,255,255,0.28) 50%, rgba(255,255,255,0) 100%);\n      transition: left 0.7s ease;\n    }\n\n    .ols-linkedin-pill:hover {\n      transform: translateY(-3px) scale(1.03);\n      box-shadow: 0 16px 34px rgba(10,102,194,0.34), 0 0 0 6px rgba(10,102,194,0.10);\n      color: #ffffff;\n    }\n\n    .ols-linkedin-pill:hover::before { left: 120%; }\n\n    .ols-linkedin-icon {\n      width: 18px;\n      height: 18px;\n      display: block;\n      flex-shrink: 0;\n    }\n\n    .ols-note-card.soft { background: linear-gradient(135deg, #ffffff 0%, var(--soft-red) 100%); }\n    .ols-note-card.purple { background: linear-gradient(135deg, #ffffff 0%, var(--soft-purple) 100%); }\n\n    .ols-note-title {\n      display: flex;\n      align-items: center;\n      gap: 14px;\n      margin-bottom: 20px;\n    }\n\n    .ols-note-icon {\n      width: 52px;\n      height: 52px;\n      border-radius: 16px;\n      background: var(--navy);\n      color: #ffffff;\n      display: grid;\n      place-items: center;\n      font-size: 24px;\n      font-weight: 800;\n      flex-shrink: 0;\n    }\n\n    .ols-note-title h2,\n    .ols-related-card h2 {\n      margin: 0;\n      font-size: clamp(28px, 3.5vw, 42px);\n      line-height: 1.15;\n      font-weight: 800;\n      color: #111827;\n      letter-spacing: -0.03em;\n    }\n\n    .ols-related-card h2 { margin-bottom: 14px; }\n\n    .ols-note-card p,\n    .ols-note-card li,\n    .ols-related-card p,\n    .ols-attribution-card p {\n      font-size: clamp(15px, 1.3vw, 18px);\n      line-height: 1.65;\n      font-weight: 300;\n      color: var(--body-text);\n    }\n\n    .ols-note-card strong,\n    .ols-related-card strong,\n    .ols-attribution-card strong {\n      font-weight: 700;\n      color: var(--navy);\n    }\n\n    .ols-key-box {\n      margin-top: 20px;\n      background: var(--soft-green);\n      border: 1px solid rgba(63, 143, 70, 0.25);\n      border-radius: 20px;\n      padding: 18px 20px;\n    }\n\n    .ols-key-box p {\n      margin: 0;\n      font-weight: 400;\n      color: var(--navy);\n    }\n\n    .ols-ert-grid {\n      display: grid;\n      grid-template-columns: repeat(2, minmax(0, 1fr));\n      gap: 18px;\n      margin-top: 26px;\n    }\n\n    .ols-ert-card {\n      position: relative;\n      display: grid;\n      grid-template-rows: auto 1fr auto;\n      min-height: 285px;\n      padding: 24px;\n      border-radius: 24px;\n      border: 1px solid rgba(28, 36, 75, 0.13);\n      background:\n        radial-gradient(circle at top right, rgba(37, 99, 235, 0.13), transparent 34%),\n        linear-gradient(135deg, #ffffff 0%, #f8fbff 100%);\n      color: var(--navy);\n      text-decoration: none;\n      overflow: hidden;\n      box-shadow: var(--inner-shadow);\n      transition: transform 0.24s ease, box-shadow 0.24s ease, border-color 0.24s ease, background 0.24s ease;\n    }\n\n    .ols-ert-card:hover {\n      transform: translateY(-6px);\n      border-color: rgba(37, 99, 235, 0.28);\n      box-shadow: 0 24px 52px rgba(28, 36, 75, 0.15);\n      color: var(--navy);\n    }\n\n    .ols-ert-card::before {\n      content: \"\";\n      position: absolute;\n      top: -60px;\n      right: -60px;\n      width: 145px;\n      height: 145px;\n      border-radius: 50%;\n      background: rgba(37, 99, 235, 0.08);\n      transition: transform 0.28s ease, background 0.28s ease;\n    }\n\n    .ols-ert-card:hover::before {\n      transform: scale(1.22);\n      background: rgba(37, 99, 235, 0.13);\n    }\n\n    .ols-ert-visual {\n      position: relative;\n      z-index: 1;\n      min-height: 94px;\n      display: flex;\n      align-items: center;\n      justify-content: center;\n      margin-bottom: 18px;\n    }\n\n    .ols-ert-icon {\n      position: relative;\n      width: 150px;\n      height: 94px;\n    }\n\n    .ols-ert-line,\n    .ols-ert-arrow,\n    .ols-ert-label-mini,\n    .ols-ert-box,\n    .ols-ert-dot,\n    .ols-ert-bubble,\n    .ols-ert-precipitate,\n    .ols-ert-swap {\n      position: absolute;\n      display: block;\n    }\n\n    .ols-ert-equation .ols-ert-box {\n      top: 25px;\n      width: 39px;\n      height: 39px;\n      border-radius: 13px;\n      display: grid;\n      place-items: center;\n      color: #ffffff;\n      font-size: 15px;\n      font-weight: 800;\n      box-shadow: 0 8px 18px rgba(28, 36, 75, 0.16);\n    }\n\n    .ols-ert-equation .b1 { left: 8px; background: var(--blue); }\n    .ols-ert-equation .b2 { left: 56px; background: var(--navy); }\n    .ols-ert-equation .b3 { right: 8px; background: var(--gold); }\n    .ols-ert-equation .ols-ert-label-mini { left: 50px; top: 34px; color: var(--navy); font-size: 19px; font-weight: 800; }\n    .ols-ert-equation .ols-ert-arrow { left: 96px; top: 43px; width: 36px; height: 3px; border-radius: 999px; background: rgba(201, 151, 58, 0.88); }\n    .ols-ert-equation .ols-ert-arrow::after { content: \"\"; position: absolute; right: -1px; top: 50%; transform: translateY(-50%); border-left: 10px solid rgba(201,151,58,0.88); border-top: 6px solid transparent; border-bottom: 6px solid transparent; }\n\n    .ols-ert-acid .ols-ert-bubble {\n      width: 18px;\n      height: 18px;\n      border-radius: 50%;\n      border: 3px solid rgba(37, 99, 235, 0.70);\n      background: rgba(238, 244, 255, 0.80);\n      box-shadow: 0 7px 16px rgba(37, 99, 235, 0.12);\n    }\n\n    .ols-ert-acid .c1 { left: 38px; top: 55px; }\n    .ols-ert-acid .c2 { left: 60px; top: 35px; transform: scale(0.82); }\n    .ols-ert-acid .c3 { left: 82px; top: 19px; transform: scale(0.68); }\n    .ols-ert-acid .flask {\n      left: 32px;\n      bottom: 9px;\n      width: 86px;\n      height: 44px;\n      border: 4px solid rgba(28, 36, 75, 0.70);\n      border-top: none;\n      border-radius: 8px 8px 28px 28px;\n      background: linear-gradient(180deg, rgba(255,247,237,0) 30%, rgba(201,151,58,0.25) 31%, rgba(201,151,58,0.25) 100%);\n    }\n\n    .ols-ert-acid .neck {\n      left: 64px;\n      top: 8px;\n      width: 22px;\n      height: 34px;\n      border: 4px solid rgba(28, 36, 75, 0.70);\n      border-bottom: none;\n      border-radius: 8px 8px 0 0;\n    }\n\n    .ols-ert-acid .ols-ert-label-mini { right: 4px; top: 8px; color: var(--gold); font-size: 13px; font-weight: 800; }\n\n    .ols-ert-ionic .ols-ert-ion {\n      min-width: 42px;\n      height: 34px;\n      padding: 0 8px;\n      border-radius: 13px;\n      display: grid;\n      place-items: center;\n      color: #ffffff;\n      font-size: 13px;\n      font-weight: 800;\n      box-shadow: 0 8px 18px rgba(28, 36, 75, 0.16);\n      background: var(--blue);\n    }\n\n    .ols-ert-ionic .i1 { left: 2px; top: 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   line-height: 1.2;\n      font-weight: 800;\n      letter-spacing: -0.02em;\n      color: #111827;\n    }\n\n    .ols-ert-card p {\n      position: relative;\n      z-index: 1;\n      margin: 0;\n      font-size: 15px;\n      line-height: 1.6;\n      font-weight: 300;\n      color: var(--body-text);\n    }\n\n    .ols-ert-card,\n    .ols-ert-card *,\n    .ols-ert-card:hover,\n    .ols-ert-card:hover *,\n    .ols-related-item,\n    .ols-related-item *,\n    .ols-related-item:hover,\n    .ols-related-item:hover * {\n      text-decoration: none !important;\n    }\n\n    .ols-ert-meta {\n      position: relative;\n      z-index: 1;\n      display: inline-flex;\n      align-items: center;\n      justify-content: center;\n      margin-top: 20px;\n      padding: 10px 14px;\n      border-radius: 999px;\n      background: var(--navy);\n      color: #ffffff;\n      font-size: 13px;\n      font-weight: 700;\n      width: fit-content;\n      transition: background 0.22s ease, transform 0.22s 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\n    \/* =========================================================\n       SIMPLE COLOURFUL LANDING PAGE CARD VISUALS\n       Clean card symbols to avoid complex diagram misalignment.\n    ========================================================= *\/\n\n    .ols-ert-grid {\n      grid-template-columns: repeat(2, minmax(0, 1fr)) !important;\n      gap: 22px !important;\n    }\n\n    .ols-ert-card {\n      display: flex !important;\n      flex-direction: column !important;\n      padding: 0 !important;\n      min-height: 0 !important;\n      border-radius: 24px !important;\n      overflow: hidden !important;\n      background: #ffffff !important;\n      box-shadow: 0 14px 34px rgba(28, 36, 75, 0.10) !important;\n      transition:\n        transform 0.28s cubic-bezier(0.34, 1.56, 0.64, 1),\n        box-shadow 0.28s ease,\n        border-color 0.28s ease !important;\n    }\n\n    .ols-ert-card:hover {\n      transform: translateY(-10px) scale(1.02) !important;\n      box-shadow: 0 28px 56px rgba(28, 36, 75, 0.16) !important;\n      border-color: rgba(37, 99, 235, 0.35) !important;\n    }\n\n    .ols-ert-card::before {\n      display: none !important;\n    }\n\n    .ols-ert-card-img-wrap {\n      position: relative;\n      width: 100%;\n      aspect-ratio: 4 \/ 3;\n      overflow: hidden;\n      background: var(--soft-blue);\n    }\n\n    .ols-ert-card-img-wrap::after {\n      content: \"\";\n      position: absolute;\n      inset: 0;\n      background: linear-gradient(180deg, transparent 42%, rgba(28, 36, 75, 0.22) 100%);\n      opacity: 0;\n      transition: opacity 0.28s ease;\n      z-index: 1;\n    }\n\n    .ols-ert-card:hover .ols-ert-card-img-wrap::after {\n      opacity: 1;\n    }\n\n    .ols-ert-card-num {\n      position: absolute;\n      top: 14px;\n      left: 14px;\n      width: 34px;\n      height: 34px;\n      border-radius: 50%;\n      background: var(--navy);\n      color: #ffffff;\n      font-size: 13px;\n      font-weight: 800;\n      display: flex;\n      align-items: center;\n      justify-content: center;\n      z-index: 4;\n      box-shadow: 0 6px 16px rgba(28, 36, 75, 0.30);\n    }\n\n    .ols-ert-card-status {\n      position: absolute;\n      top: 14px;\n      right: 14px;\n      padding: 5px 11px;\n      border-radius: 999px;\n      background: #eaf3de;\n      color: #3B6D11;\n      font-size: 10px;\n      font-weight: 800;\n      letter-spacing: 0.01em;\n      z-index: 4;\n      box-shadow: 0 6px 16px rgba(28, 36, 75, 0.12);\n    }\n\n    .ols-ert-card-body {\n      padding: 20px 20px 24px;\n      flex: 1;\n      display: flex;\n      flex-direction: column;\n      gap: 8px;\n      background: #ffffff;\n    }\n\n    .ols-ert-card-body h3 {\n      margin: 0 !important;\n      font-size: 18px !important;\n      line-height: 1.25 !important;\n      font-weight: 800 !important;\n      letter-spacing: -0.025em !important;\n      color: #111827 !important;\n    }\n\n    .ols-ert-card-body p {\n      margin: 0 !important;\n      font-size: 13px !important;\n      line-height: 1.62 !important;\n      font-weight: 300 !important;\n      color: var(--grey-text) !important;\n    }\n\n    .ols-ert-meta {\n      margin-top: 12px !important;\n      padding: 0 !important;\n      background: transparent !important;\n      color: var(--blue) !important;\n      font-size: 13px !important;\n      font-weight: 800 !important;\n      display: inline-flex !important;\n      align-items: center !important;\n      gap: 6px !important;\n      transition: transform 0.22s ease, color 0.22s ease !important;\n    }\n\n    .ols-ert-meta::after {\n      content: \"\u2192\";\n      font-size: 16px;\n      line-height: 1;\n      transition: transform 0.22s ease;\n    }\n\n    .ols-ert-card:hover .ols-ert-meta {\n      background: transparent !important;\n      transform: none !important;\n      color: var(--blue) !important;\n    }\n\n    .ols-ert-card:hover .ols-ert-meta::after {\n      transform: translateX(4px);\n    }\n\n    .ols-ert-visual {\n      position: absolute !important;\n      inset: 0 !important;\n      min-height: 0 !important;\n      margin: 0 !important;\n      padding: 32px 24px 24px !important;\n      overflow: hidden;\n      display: flex !important;\n      align-items: center !important;\n      justify-content: center !important;\n      z-index: 0 !important;\n    }\n\n    .ols-ert-visual::before,\n    .ols-ert-visual::after {\n      content: \"\";\n      position: absolute;\n      border-radius: 999px;\n      opacity: 0.72;\n      filter: blur(1px);\n      z-index: 0;\n    }\n\n    .ols-ert-visual::before {\n      width: 170px;\n      height: 170px;\n      left: -58px;\n      bottom: -66px;\n      background: rgba(255, 255, 255, 0.35);\n    }\n\n    .ols-ert-visual::after {\n      width: 118px;\n      height: 118px;\n      right: -42px;\n      top: -34px;\n      background: rgba(255, 255, 255, 0.28);\n    }\n\n    .ols-ert-visual-panel {\n      position: relative;\n      z-index: 2;\n      width: min(84%, 260px);\n      min-height: 150px;\n      border-radius: 24px;\n      border: 1px solid rgba(255, 255, 255, 0.48);\n      background: rgba(255, 255, 255, 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class=\"ols-sidebar\">\n  <div class=\"ols-sidebar-header\">\n    <h3>Revision Notes<\/h3>\n    <p>OCR A Level Chemistry A<\/p>\n  <\/div>\n  <div class=\"ols-topic-group\">\n    <h4>2.1.2 Compounds, Formulae and Equations<\/h4>\n    <ul class=\"ols-topic-list\">\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-2-compounds-formulae-and-equations\/\">Section overview<\/a><\/li>\n<li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-2-compounds-formulae-and-equations\/ions-and-ionic-formulae\/\">Ions and Ionic Formulae<\/a><\/li>\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-2-compounds-formulae-and-equations\/equations-and-reaction-types\/\">Equations and Reaction Types<\/a>\n        <ul class=\"ols-subtopic-list\">\n          <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-2-compounds-formulae-and-equations\/equations-and-reaction-types\/writing-chemical-equations\/\">Writing Chemical Equations<\/a><\/li>\n          <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-2-compounds-formulae-and-equations\/equations-and-reaction-types\/ionic-and-full-equations\/\">Ionic and Full Equations<\/a><\/li>\n          <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-4-acids\/typical-reactions-of-acids\/\">Typical Reactions of Acids<\/a><\/li>\n        <\/ul>\n      <\/li>\n    <\/ul>\n  <\/div>\n  <div class=\"ols-topic-group\">\n    <h4>Other OCR Sections<\/h4>\n    <ul class=\"ols-topic-list\">\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-1-atomic-structure-and-isotopes\/\">2.1.1 Atomic Structure and Isotopes<\/a><\/li>\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-3-amount-of-substance\/\">2.1.3 Amount of Substance<\/a><\/li>\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-4-acids\/\">2.1.4 Acids<\/a><\/li>\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-2-1-electron-structure\/\">2.2.1 Electron Structure<\/a><\/li>\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-2-2-bonding-and-structure\/\">2.2.2 Bonding and Structure<\/a><\/li>\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/3-1-1-periodicity\/\">3.1.1 Periodicity<\/a><\/li>\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/4-1-1-basic-concepts-of-organic-chemistry\/\">4.1.1 Basic Concepts of Organic Chemistry<\/a><\/li>\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/4-1-2-alkanes\/\">4.1.2 Alkanes<\/a><\/li>\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/4-1-3-alkenes\/\">4.1.3 Alkenes<\/a><\/li>\n    <\/ul>\n  <\/div>\n<\/aside>\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 = 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\/\n<a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-2-compounds-formulae-and-equations\/\">2.1.2 Compounds, Formulae and Equations<\/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 OCR. 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\">Paper 1 and 2<\/div>\n<div class=\"ols-badge\">2.1.2 Compounds, Formulae and Equations<\/div>\n<div class=\"ols-badge\">H432\/01 and H432\/02<\/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-sub-cards-grid\">\n        <a class=\"ols-sub-card ols-sub-card--available\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-2-compounds-formulae-and-equations\/equations-and-reaction-types\/writing-chemical-equations\/\">\n          <div class=\"ols-sub-card-img-wrap\">\n            <div class=\"ols-sub-visual ols-sub-visual--particles\">\n              <div class=\"ols-sub-visual-panel\">\n                <div class=\"ols-sub-visual-kicker\">Balanced equations<\/div>\n                <div class=\"ols-sub-particle-diagram\" aria-hidden=\"true\"><span class=\"ols-sub-particle-dot d1\"><\/span><span class=\"ols-sub-particle-dot d2\"><\/span><span class=\"ols-sub-particle-dot d3\"><\/span><\/div>\n                <div class=\"ols-sub-visual-main ols-sub-visual-main--mid\">Writing Chemical Equations<\/div>\n                <div class=\"ols-sub-visual-sub\">formulae, coefficients and state symbols<\/div>\n              <\/div>\n            <\/div>\n            <div class=\"ols-sub-card-num\">1<\/div>\n            <span class=\"ols-sub-card-status ols-sub-card-status--available\">Available<\/span>\n          <\/div>\n          <div class=\"ols-sub-card-body\">\n            <p class=\"ols-sub-card-title\">Writing Chemical Equations<\/p>\n            <p class=\"ols-sub-card-desc\">Revise word equations, symbol equations, balancing equations and the correct use of state symbols.<\/p>\n            <span class=\"ols-sub-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        <a class=\"ols-sub-card ols-sub-card--available\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-4-acids\/typical-reactions-of-acids\/\">\n          <div class=\"ols-sub-card-img-wrap\">\n            <div class=\"ols-sub-visual ols-sub-visual--particles\">\n              <div class=\"ols-sub-visual-panel\">\n                <div class=\"ols-sub-visual-kicker\">Reaction patterns<\/div>\n                <div class=\"ols-sub-particle-diagram\" aria-hidden=\"true\"><span class=\"ols-sub-particle-dot d1\"><\/span><span class=\"ols-sub-particle-dot d2\"><\/span><span class=\"ols-sub-particle-dot d3\"><\/span><\/div>\n                <div class=\"ols-sub-visual-main ols-sub-visual-main--mid\">Typical Reactions of Acids<\/div>\n                <div class=\"ols-sub-visual-sub\">salts, water, hydrogen and carbon dioxide<\/div>\n              <\/div>\n            <\/div>\n            <div class=\"ols-sub-card-num\">2<\/div>\n            <span class=\"ols-sub-card-status ols-sub-card-status--available\">Available<\/span>\n          <\/div>\n          <div class=\"ols-sub-card-body\">\n            <p class=\"ols-sub-card-title\">Typical Reactions of Acids<\/p>\n            <p class=\"ols-sub-card-desc\">Learn the common products formed when acids react with metals, bases, alkalis and carbonates.<\/p>\n            <span class=\"ols-sub-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        <a class=\"ols-sub-card ols-sub-card--available\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-2-compounds-formulae-and-equations\/ionic-and-full-equations\/\">\n          <div class=\"ols-sub-card-img-wrap\">\n            <div class=\"ols-sub-visual ols-sub-visual--particles\">\n              <div class=\"ols-sub-visual-panel\">\n                <div class=\"ols-sub-visual-kicker\">Net ionic change<\/div>\n                <div class=\"ols-sub-particle-diagram\" aria-hidden=\"true\"><span class=\"ols-sub-particle-dot d1\"><\/span><span class=\"ols-sub-particle-dot d2\"><\/span><span class=\"ols-sub-particle-dot d3\"><\/span><\/div>\n                <div class=\"ols-sub-visual-main\">Ionic Equations<\/div>\n                <div class=\"ols-sub-visual-sub\">reacting ions and spectator ions<\/div>\n              <\/div>\n            <\/div>\n            <div class=\"ols-sub-card-num\">3<\/div>\n            <span class=\"ols-sub-card-status ols-sub-card-status--available\">Available<\/span>\n          <\/div>\n          <div class=\"ols-sub-card-body\">\n            <p class=\"ols-sub-card-title\">Ionic Equations<\/p>\n            <p class=\"ols-sub-card-desc\">Learn how ionic equations show only the reacting ions and remove spectator ions from chemical equations.<\/p>\n            <span class=\"ols-sub-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      <\/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 Pages<\/h2>\n        <p>Use these pages to connect equations and reaction types with formulae, relative formula mass, empirical formulae and amounts 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\/ocr-a\/2-1-3-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\/ocr-a\/2-1-2-compounds-formulae-and-equations\/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\/ocr-a\/2-1-4-acids\/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\/ocr-a\/2-1-2-compounds-formulae-and-equations\/ionic-and-full-equations\/\">Ionic Equations<\/a>\n          <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-2-compounds-formulae-and-equations\/\">this section Overview<\/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\/ocr-a\/2-1-2-compounds-formulae-and-equations\/equations-and-reaction-types\/#webpage\",\n      \"url\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-2-compounds-formulae-and-equations\/equations-and-reaction-types\/\",\n      \"name\": \"Equations and Reaction Types - OCR A Level Chemistry A\",\n      \"description\": \"OCR A Level Chemistry A this section 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\/ocr-a\/2-1-2-compounds-formulae-and-equations\/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\": \"OCR A\",\n          \"item\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/\"\n        },\n        {\n          \"@type\": \"ListItem\",\n          \"position\": 4,\n          \"name\": \"2.1.2 Compounds, Formulae and Equations\",\n          \"item\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-2-compounds-formulae-and-equations\/\"\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\/ocr-a\/2-1-2-compounds-formulae-and-equations\/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 \/ OCR A \/ 2.1.2 Compounds, Formulae and Equations \/ 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 OCR. Each card links to a focused page covering chemical equations, acid reactions and [&hellip;]<\/p>\n","protected":false},"author":12,"featured_media":0,"parent":8048,"menu_order":1,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-8052","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-json\/wp\/v2\/pages\/8052","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=8052"}],"version-history":[{"count":0,"href":"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-json\/wp\/v2\/pages\/8052\/revisions"}],"up":[{"embeddable":true,"href":"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-json\/wp\/v2\/pages\/8048"}],"wp:attachment":[{"href":"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-json\/wp\/v2\/media?parent=8052"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}