{"id":10707,"date":"2026-09-26T13:54:23","date_gmt":"2026-09-26T12:54:23","guid":{"rendered":"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-9-kinetics-and-equilibria\/9a-kinetics\/"},"modified":"2026-10-04T23:03:10","modified_gmt":"2026-10-04T22:03:10","slug":"9a-kinetics","status":"publish","type":"page","link":"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-9-kinetics-and-equilibria\/9a-kinetics\/","title":{"rendered":"Topic 9A Kinetics"},"content":{"rendered":"\n<section class=\"ols-revision-page ols-topic-9a-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\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-wrap: wrap;\n      gap: 12px;\n      margin-bottom: 22px;\n    }\n\n    .ols-badge {\n      display: inline-flex;\n      align-items: center;\n      padding: 9px 14px;\n      border-radius: 999px;\n      background: #ffffff;\n      border: 1px solid var(--border);\n      font-size: 15px;\n      font-weight: 600;\n      color: var(--navy);\n    }\n\n    .ols-author {\n      display: flex;\n      align-items: center;\n      gap: 20px;\n      padding: 28px;\n      border-radius: 28px;\n      background: linear-gradient(135deg, #ffffff 0%, #f8fbff 100%);\n      border: 1px solid rgba(28,36,75,0.12);\n      box-shadow: 0 18px 45px rgba(28,36,75,0.10);\n      margin-top: 22px;\n    }\n\n    .ols-author-avatar-img {\n      width: 92px;\n      height: 92px;\n      border-radius: 50%;\n      object-fit: cover;\n      object-position: center;\n      flex-shrink: 0;\n      border: 4px solid #ffffff;\n      box-shadow: 0 14px 32px rgba(28,36,75,0.18), 0 0 0 1px rgba(28,36,75,0.10);\n      transition: transform 0.25s ease, box-shadow 0.25s ease;\n    }\n\n    .ols-author:hover .ols-author-avatar-img {\n      transform: scale(1.04);\n      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(3, 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-ion,\n    .ols-ert-pull,\n    .ols-ert-lattice {\n      position: absolute;\n      display: block;\n    }\n\n    .ols-ert-ionic .ols-ert-ion {\n      width: 40px;\n      height: 40px;\n      border-radius: 50%;\n      display: grid;\n      place-items: center;\n      font-size: 15px;\n      font-weight: 800;\n      color: #ffffff;\n      box-shadow: 0 12px 24px rgba(28,36,75,0.14);\n    }\n\n    .ols-ert-ionic .ols-ert-ion.left {\n      left: 24px;\n      top: 24px;\n      background: var(--blue);\n    }\n\n    .ols-ert-ionic .ols-ert-ion.right {\n      right: 24px;\n      top: 24px;\n      background: var(--gold);\n    }\n\n    .ols-ert-ionic .ols-ert-arrow {\n      left: 68px;\n      top: 43px;\n      width: 36px;\n      height: 3px;\n      border-radius: 999px;\n      background: rgba(28, 36, 75, 0.65);\n    }\n\n    .ols-ert-ionic .ols-ert-arrow::after {\n      content: \"\";\n      position: absolute;\n      right: -1px;\n      top: 50%;\n      transform: translateY(-50%);\n      border-left: 10px solid rgba(28,36,75,0.65);\n      border-top: 6px solid transparent;\n      border-bottom: 6px solid transparent;\n    }\n\n    .ols-ert-ionic .ols-ert-label-mini {\n      left: 39px;\n      bottom: 8px;\n      color: var(--blue);\n      font-size: 13px;\n      font-weight: 800;\n    }\n\n    .ols-ert-polarisation .ols-ert-ion.large {\n      left: 21px;\n      top: 18px;\n      width: 58px;\n      height: 58px;\n      border-radius: 50%;\n      border: 3px solid rgba(37, 99, 235, 0.34);\n      background: rgba(238, 244, 255, 0.96);\n      box-shadow: inset -10px 0 0 rgba(37,99,235,0.10), 0 12px 24px rgba(28,36,75,0.10);\n    }\n\n    .ols-ert-polarisation .ols-ert-ion.small {\n      right: 33px;\n      top: 30px;\n      width: 34px;\n      height: 34px;\n      border-radius: 50%;\n      background: var(--gold);\n      box-shadow: 0 10px 22px rgba(201,151,58,0.20);\n    }\n\n    .ols-ert-polarisation .ols-ert-pull {\n      left: 82px;\n      top: 44px;\n      width: 34px;\n      height: 3px;\n      border-radius: 999px;\n      background: rgba(201,151,58,0.88);\n    }\n\n    .ols-ert-polarisation .ols-ert-pull::before,\n    .ols-ert-polarisation .ols-ert-pull::after {\n      content: \"\";\n      position: absolute;\n      top: 50%;\n      transform: translateY(-50%);\n      border-top: 6px solid transparent;\n      border-bottom: 6px solid transparent;\n    }\n\n    .ols-ert-polarisation .ols-ert-pull::before {\n      left: -1px;\n      border-right: 10px solid rgba(201,151,58,0.88);\n    }\n\n    .ols-ert-polarisation .ols-ert-pull::after {\n      right: -1px;\n      border-left: 10px solid rgba(201,151,58,0.88);\n    }\n\n    .ols-ert-polarisation .ols-ert-label-mini {\n      left: 34px;\n      bottom: 8px;\n      color: var(--gold);\n      font-size: 13px;\n      font-weight: 800;\n    }\n\n    .ols-ert-properties .ols-ert-lattice {\n      left: 31px;\n      top: 13px;\n      width: 88px;\n      height: 68px;\n      background:\n        radial-gradient(circle at 12px 12px, var(--blue) 0 7px, transparent 8px),\n        radial-gradient(circle at 44px 12px, var(--gold) 0 7px, transparent 8px),\n        radial-gradient(circle at 76px 12px, var(--blue) 0 7px, transparent 8px),\n        radial-gradient(circle at 12px 36px, var(--gold) 0 7px, transparent 8px),\n        radial-gradient(circle at 44px 36px, var(--blue) 0 7px, transparent 8px),\n        radial-gradient(circle at 76px 36px, var(--gold) 0 7px, transparent 8px),\n        radial-gradient(circle at 12px 60px, var(--blue) 0 7px, transparent 8px),\n        radial-gradient(circle at 44px 60px, var(--gold) 0 7px, transparent 8px),\n        radial-gradient(circle at 76px 60px, var(--blue) 0 7px, transparent 8px);\n      border-radius: 18px;\n      box-shadow: 0 12px 26px rgba(28,36,75,0.10);\n    }\n\n    .ols-ert-properties .ols-ert-lattice::before {\n      content: \"\";\n      position: absolute;\n      inset: 8px 6px;\n      background:\n        linear-gradient(90deg, rgba(28,36,75,0.16) 1px, transparent 1px) 0 0 \/ 32px 24px,\n        linear-gradient(0deg, rgba(28,36,75,0.16) 1px, transparent 1px) 0 0 \/ 32px 24px;\n      border-radius: 14px;\n      pointer-events: none;\n    }\n\n    .ols-ert-properties .ols-ert-label-mini {\n      left: 43px;\n      bottom: 7px;\n      color: var(--blue);\n      font-size: 13px;\n      font-weight: 800;\n    }\n\n    .ols-ert-card h3 {\n      position: relative;\n      z-index: 1;\n      margin: 0 0 10px;\n      font-size: 23px;\n      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-ert-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }\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-grid { grid-template-columns: 1fr; }\n      .ols-ert-card { min-height: 255px; }\n      .ols-related-grid { grid-template-columns: 1fr; }\n    }\n  :root { --ols-navy: #1C244B; --ols-blue: #467FF7; --ols-soft-blue: #EEF4FF; --ols-border: rgba(28, 36, 75, 0.12); --ols-shadow: 0 18px 45px rgba(28, 36, 75, 0.12); --ols-shadow-soft: 0 10px 28px rgba(28, 36, 75, 0.09); --ols-muted: #4b5575; }\n    .ols-sub-cards-grid { margin-top: 26px; }\n    .ols-sub-cards-grid {\n      display: grid;\n      grid-template-columns: repeat(3, minmax(0, 1fr));\n      gap: 20px;\n    }\n\n    .ols-sub-card {\n      display: flex;\n      flex-direction: column;\n      background: #ffffff;\n      border: 1px solid var(--ols-border);\n      border-radius: 22px;\n      overflow: hidden;\n      box-shadow: var(--ols-shadow-soft);\n      text-decoration: none;\n      color: var(--ols-navy);\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;\n      position: relative;\n    }\n\n    .ols-sub-card.ols-sub-card--available:hover {\n      transform: translateY(-10px) scale(1.02);\n      box-shadow: 0 28px 56px rgba(28, 36, 75, 0.16);\n      border-color: rgba(70, 127, 247, 0.35);\n    }\n\n    .ols-sub-card.ols-sub-card--available:hover .ols-sub-card-img-wrap::after {\n      opacity: 1;\n    }\n\n    .ols-sub-card-img-wrap {\n      position: relative;\n      width: 100%;\n      aspect-ratio: 4 \/ 3;\n      background: var(--ols-soft-blue);\n      overflow: hidden;\n    }\n\n    .ols-sub-card-img-wrap::after {\n      content: \"\";\n      position: absolute;\n      inset: 0;\n      background: linear-gradient(180deg, transparent 40%, rgba(28, 36, 75, 0.20) 100%);\n      opacity: 0;\n      transition: opacity 0.28s ease;\n      z-index: 1;\n    }\n\n    .ols-sub-card-num {\n      position: absolute;\n      top: 12px;\n      left: 12px;\n      width: 32px;\n      height: 32px;\n      border-radius: 50%;\n      background: var(--ols-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: 3;\n      box-shadow: 0 4px 12px rgba(28, 36, 75, 0.28);\n    }\n\n    .ols-sub-card-status {\n      position: absolute;\n      top: 12px;\n      right: 12px;\n      padding: 4px 10px;\n      border-radius: 999px;\n      font-size: 10px;\n      font-weight: 700;\n      z-index: 3;\n    }\n\n    .ols-sub-card-status--available {\n      background: #eaf3de;\n      color: #3B6D11;\n    }\n\n    .ols-sub-card-body {\n      padding: 18px 18px 22px;\n      flex: 1;\n      display: flex;\n      flex-direction: column;\n      gap: 6px;\n    }\n\n    .ols-sub-card-title {\n      font-size: 14px;\n      font-weight: 700;\n      color: var(--ols-navy);\n      line-height: 1.35;\n      margin: 0;\n    }\n\n    .ols-sub-card-desc {\n      font-size: 12px;\n      font-weight: 300;\n      color: var(--ols-muted);\n      line-height: 1.6;\n      margin: 0;\n    }\n\n    .ols-sub-card-cta {\n      display: inline-flex;\n      align-items: center;\n      gap: 5px;\n      margin-top: 10px;\n      font-size: 12px;\n      font-weight: 700;\n      color: var(--ols-blue);\n    }\n\n    .ols-sub-card-cta svg {\n      width: 14px;\n      height: 14px;\n      transition: transform 0.2s ease;\n    }\n\n    .ols-sub-card--available:hover .ols-sub-card-cta svg {\n      transform: 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var(--ols-navy);\n    }\n\n    \/* =========================================================\n       SPECIFICATION SECTION\n    ========================================================= *\/\n    @media (max-width: 1024px) { .ols-sub-cards-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); } }\n    @media (max-width: 640px) { .ols-sub-cards-grid { grid-template-columns: 1fr; gap: 14px; } }\n    .ols-sub-card, .ols-sub-card *, .ols-sub-card:hover, .ols-sub-card:hover * { text-decoration: none !important; }\n    .ols-sub-card--soon { filter: grayscale(1); opacity: 0.62; cursor: not-allowed; }\n    .ols-sub-card-status--soon { background: #6b7280; color: #ffffff; }\n    .ols-sub-cards-grid .ols-sub-visual-main.ols-sub-visual-main { font-size: clamp(19px, 1.9vw, 26px) !important; line-height: 1.08; }\n    .ols-sub-cards-grid .ols-sub-visual-panel { width: min(86%, 270px); padding: 14px; }\n    .ols-sub-card .ols-sub-card-title.ols-sub-card-title { font-size: 14px; font-weight: 700; color: #1C244B; line-height: 1.35; margin: 0; }\n    .ols-sub-card .ols-sub-card-desc.ols-sub-card-desc { font-size: 12px; font-weight: 300; color: #4b5575; line-height: 1.6; margin: 0; }\n    .ols-sub-cards-grid .ols-sub-visual-main.ols-sub-visual-main--long { font-size: clamp(15px, 1.35vw, 19px) !important; line-height: 1.12; letter-spacing: -0.03em; }\n    .ols-sub-cards-grid .ols-sub-visual-main.ols-sub-visual-main--mid { font-size: clamp(17px, 1.6vw, 22px) !important; }\n    .ols-sub-cards-grid .ols-sub-visual-sub { font-size: 11px; line-height: 1.35; }\n<\/style>\n\n  <aside class=\"ols-sidebar\">\n  <div class=\"ols-sidebar-header\">\n    <h3>Revision Notes<\/h3>\n    <p>A Level Chemistry<\/p>\n  <\/div>\n\n  <div class=\"ols-topic-group\">\n    <h4>Topic 9 Kinetics &amp; Equilibria<\/h4>\n\n    <ul class=\"ols-topic-list\">\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-9-kinetics-and-equilibria\/\">Topic 9 Overview<\/a>\n      <\/li>\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-9-kinetics-and-equilibria\/9a-kinetics\/\">Topic 9A Kinetics<\/a>\n        <ul class=\"ols-subtopic-list\">\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-9-kinetics-and-equilibria\/9a-kinetics\/collision-theory-and-rates-of-reaction\/\">Collision Theory and Rates of Reaction<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-9-kinetics-and-equilibria\/9a-kinetics\/measuring-and-calculating-rates\/\">Measuring and Calculating Rates<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-9-kinetics-and-equilibria\/9a-kinetics\/maxwell-boltzmann-distribution\/\">The Maxwell\u2013Boltzmann Distribution<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-9-kinetics-and-equilibria\/9a-kinetics\/catalysts-and-reaction-profiles\/\">Catalysts and Reaction Profiles<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/core-practicals\/cp-9a-9b-iodine-propanone-and-clock-reaction-kinetics\/\">Core Practical 9A\/9B<\/a>\n          <\/li>\n        <\/ul>\n      <\/li>\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-9-kinetics-and-equilibria\/9b-equilibria\/\">Topic 9B Equilibria<\/a>\n        <ul class=\"ols-subtopic-list\">\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-9-kinetics-and-equilibria\/9b-equilibria\/dynamic-equilibrium\/\">Dynamic Equilibrium<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-9-kinetics-and-equilibria\/9b-equilibria\/le-chateliers-principle\/\">Le Chatelier's Principle<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-9-kinetics-and-equilibria\/9b-equilibria\/equilibria-in-industry\/\">Equilibria in Industry<\/a>\n          <\/li>\n        <\/ul>\n      <\/li>\n    <\/ul>\n  <\/div>\n\n  <div class=\"ols-topic-group\">\n    <h4>Other Topics<\/h4>\n\n    <ul class=\"ols-topic-list\">\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-6-energetics\/\">Topic 6 Energetics<\/a>\n      <\/li>\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-7-intermolecular-forces\/\">Topic 7 Intermolecular Forces<\/a>\n      <\/li>\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/\">Topic 8 Redox &amp; Groups 1, 2 and 7<\/a>\n      <\/li>\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/core-practicals\/\">Core Practicals<\/a>\n      <\/li>\n    <\/ul>\n  <\/div>\n<\/aside>\n\n<script>\r\n(function() {\r\n  function normalisePath(path) {\r\n    return String(path || '')\r\n      .split('?')[0]\r\n      .split('#')[0]\r\n      .replace(\/\\\/+$\/, '')\r\n      .toLowerCase();\r\n  }\r\n\r\n  function highlightActive() {\r\n    var sidebar = document.querySelector('.ols-sidebar');\r\n    if (!sidebar) return false;\r\n\r\n    var currentPath = normalisePath(window.location.pathname);\r\n    var links = sidebar.querySelectorAll('a[href]');\r\n    var matched = null;\r\n    var matchedLength = 0;\r\n\r\n    sidebar.querySelectorAll('.active, .active-main, .parent-active').forEach(function(item) {\r\n      item.classList.remove('active', 'active-main', 'parent-active');\r\n    });\r\n\r\n    sidebar.querySelectorAll('a[data-ols-disabled-parent=\"1\"], a[aria-current]').forEach(function(a) {\r\n      a.removeAttribute('aria-current');\r\n      a.removeAttribute('tabindex');\r\n      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}\r\n})();\r\n<\/script>\r\n\n\n  <main class=\"ols-main\">\n    <nav class=\"ols-breadcrumbs\" aria-label=\"Breadcrumb\">\n      <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/\">Revision Notes<\/a> \/\n      <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/\">A Level Chemistry<\/a> \/\n      <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/\">Edexcel International<\/a> \/\n      <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-9-kinetics-and-equilibria\/\">Topic 9 Kinetics and Equilibria<\/a> \/\n      <span>Topic 9A Kinetics<\/span>\n    <\/nav>\n\n    <header class=\"ols-title-card\">\n      <h1>Topic 9A Kinetics<\/h1>\n      <p class=\"ols-page-intro\">Use this landing page to move between the four Kinetics revision pages of Topic 9. Each card links to a focused page with inline checks, worked examples and exam-style FAQs.<\/p>\n\n      <div class=\"ols-badges\">\n        <div class=\"ols-badge\">Exam board: Edexcel International<\/div>\n        <div class=\"ols-badge\">Unit 2: WCH12\/01<\/div>\n        <div class=\"ols-badge\">Topic 9A Kinetics<\/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 a Kinetics Page<\/h2>\n      <\/div>\n\n      <p>Kinetics is the study of how fast reactions go and why. These pages build collision theory and activation energy, show how rates are measured and calculated from graphs, explain the Maxwell\u2013Boltzmann distribution that underlies the effect of temperature, and finish with catalysts: how they lower the activation energy and why industry depends on them.<\/p>\n\n      <div class=\"ols-key-box\">\n        <p><strong>Key idea:<\/strong> Every rate explanation comes back to two questions: how often do the particles collide, and what fraction of those collisions have energy at or above the activation energy?<\/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\/edexcel-international\/topic-9-kinetics-and-equilibria\/9a-kinetics\/collision-theory-and-rates-of-reaction\/\">\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\">Collision theory<\/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\">Rates of Reaction<\/div>\n                <div class=\"ols-sub-visual-sub\">E\u2090, concentration, temperature<\/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\">Collision Theory and Rates of Reaction<\/p>\n            <p class=\"ols-sub-card-desc\">Collision theory: rate of reaction, activation energy, effective collisions and the effects of concentration, pressure, surface area and temperature.<\/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\n        <a class=\"ols-sub-card ols-sub-card--available\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-9-kinetics-and-equilibria\/9a-kinetics\/measuring-and-calculating-rates\/\">\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\">Gradients<\/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\">Measuring Rates<\/div>\n                <div class=\"ols-sub-visual-sub\">tangents, 1\/t, mol dm\u207b\u00b3 s\u207b\u00b9<\/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\">Measuring and Calculating Rates<\/p>\n            <p class=\"ols-sub-card-desc\">Measuring rates: mass, gas volume and clock methods, rate = 1\/time, tangents and initial rate on concentration\u2013time graphs.<\/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\n        <a class=\"ols-sub-card ols-sub-card--available\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-9-kinetics-and-equilibria\/9a-kinetics\/maxwell-boltzmann-distribution\/\">\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\">Energy spread<\/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\">Maxwell\u2013 Boltzmann<\/div>\n                <div class=\"ols-sub-visual-sub\">temperature, E\u2090, catalyst<\/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\">The Maxwell\u2013Boltzmann Distribution<\/p>\n            <p class=\"ols-sub-card-desc\">The Maxwell\u2013Boltzmann distribution: shape, activation energy, the effect of temperature and the effect of a catalyst on the proportion of molecules that can react.<\/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\n        <a class=\"ols-sub-card ols-sub-card--available\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-9-kinetics-and-equilibria\/9a-kinetics\/catalysts-and-reaction-profiles\/\">\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\">Lower E\u2090<\/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\">Catalysts<\/div>\n                <div class=\"ols-sub-visual-sub\">profiles, surfaces, industry<\/div>\n              <\/div>\n            <\/div>\n            <div class=\"ols-sub-card-num\">4<\/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\">Catalysts and Reaction Profiles<\/p>\n            <p class=\"ols-sub-card-desc\">Catalysts: lower activation energy, reaction profiles with the intermediate, homogeneous and heterogeneous catalysis, and the economic and environmental benefits.<\/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 collision theory so the vocabulary is secure, then the measuring page for the practical and graph skills, then the Maxwell\u2013Boltzmann distribution and catalysts, which together explain temperature and catalyst effects at the molecular level.<\/p>\n\n      <div class=\"ols-key-box\">\n        <p><strong>Exam focus:<\/strong> Name the factor, say what it changes (collision frequency, or the proportion of collisions with E \u2265 E\u2090, or both) and link that to the rate. The activation energy only moves for a catalyst.<\/p>\n      <\/div>\n    <\/article>\n\n    <section class=\"ols-related-card\">\n      <h2>Related Topic 9 Pages<\/h2>\n      <p>Use these pages to connect kinetics with the other half of Topic 9 and with the core practical.<\/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-9-kinetics-and-equilibria\/9b-equilibria\/\">Topic 9B Equilibria<\/a>\n        <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-9-kinetics-and-equilibria\/\">Topic 9 Overview<\/a>\n        <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/core-practicals\/cp-9a-9b-iodine-propanone-and-clock-reaction-kinetics\/\">CP 9A\/9B Iodine\u2013Propanone and Clock Reaction Kinetics<\/a>\n        <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-6-energetics\/\">Topic 6 Energetics<\/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. 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