{"id":8065,"date":"2026-09-15T08:23:59","date_gmt":"2026-09-15T07:23:59","guid":{"rendered":"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-3-amount-of-substance\/calculations-with-solutions-and-gases\/"},"modified":"2026-09-15T08:23:59","modified_gmt":"2026-09-15T07:23:59","slug":"calculations-with-solutions-and-gases","status":"publish","type":"page","link":"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-3-amount-of-substance\/calculations-with-solutions-and-gases\/","title":{"rendered":"Calculations with Solutions and Gases"},"content":{"rendered":"\n<section class=\"ols-revision-page ols-calculations-solutions-gases-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-main {\n      min-width: 0;\n      max-width: 970px;\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-csg-grid {\n      display: grid;\n      grid-template-columns: repeat(3, minmax(0, 1fr));\n      gap: 18px;\n      margin-top: 26px;\n    }\n\n    .ols-csg-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-csg-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-csg-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-csg-card:hover::before {\n      transform: scale(1.22);\n      background: rgba(37, 99, 235, 0.13);\n    }\n\n    .ols-csg-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-csg-icon {\n      position: relative;\n      width: 150px;\n      height: 94px;\n    }\n\n    .ols-csg-line,\n    .ols-csg-arrow,\n    .ols-csg-label-mini,\n    .ols-csg-box,\n    .ols-csg-dot,\n    .ols-csg-bubble,\n    .ols-csg-precipitate,\n    .ols-csg-swap {\n      position: absolute;\n      display: block;\n    }\n\n    .ols-csg-equation .ols-csg-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-csg-equation .b1 { left: 8px; background: var(--blue); }\n    .ols-csg-equation .b2 { left: 56px; background: var(--navy); }\n    .ols-csg-equation .b3 { right: 8px; background: var(--gold); }\n    .ols-csg-equation .ols-csg-label-mini { left: 50px; top: 34px; color: var(--navy); font-size: 19px; font-weight: 800; }\n    .ols-csg-equation .ols-csg-arrow { left: 96px; top: 43px; width: 36px; height: 3px; border-radius: 999px; background: rgba(201, 151, 58, 0.88); }\n    .ols-csg-equation .ols-csg-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-csg-acid .ols-csg-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-csg-acid .c1 { left: 38px; top: 55px; }\n    .ols-csg-acid .c2 { left: 60px; top: 35px; transform: scale(0.82); }\n    .ols-csg-acid .c3 { left: 82px; top: 19px; transform: scale(0.68); }\n    .ols-csg-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-csg-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-csg-acid .ols-csg-label-mini { right: 4px; top: 8px; color: var(--gold); font-size: 13px; font-weight: 800; }\n\n    .ols-csg-displacement .ols-csg-line {\n      height: 4px;\n      border-radius: 999px;\n      background: rgba(28, 36, 75, 0.28);\n    }\n\n    .ols-csg-displacement .l1 { left: 16px; right: 16px; top: 32px; }\n    .ols-csg-displacement .l2 { left: 16px; right: 16px; bottom: 30px; }\n    .ols-csg-displacement .ols-csg-dot {\n      width: 23px;\n      height: 23px;\n      border-radius: 50%;\n      display: grid;\n      place-items: center;\n      color: #ffffff;\n      font-size: 12px;\n      font-weight: 800;\n      box-shadow: 0 8px 18px rgba(28,36,75,0.18);\n    }\n\n    .ols-csg-displacement .d1 { left: 22px; top: 22px; background: var(--blue); }\n    .ols-csg-displacement .d2 { right: 22px; bottom: 20px; background: var(--navy); }\n    .ols-csg-displacement .d3 { right: 22px; top: 22px; background: var(--gold); }\n    .ols-csg-displacement .d4 { left: 22px; bottom: 20px; background: #c81e1e; }\n    .ols-csg-displacement .ols-csg-swap { left: 60px; top: 35px; color: var(--gold); font-size: 28px; font-weight: 800; transform: rotate(-12deg); }\n\n    .ols-csg-precipitation .tube {\n      top: 10px;\n      width: 42px;\n      height: 76px;\n      border: 4px solid rgba(28, 36, 75, 0.68);\n      border-top: none;\n      border-radius: 0 0 22px 22px;\n      background: linear-gradient(180deg, rgba(238,244,255,0) 34%, rgba(238,244,255,0.90) 35%, rgba(238,244,255,0.90) 100%);\n    }\n\n    .ols-csg-precipitation .t1 { left: 19px; transform: rotate(-8deg); }\n    .ols-csg-precipitation .t2 { right: 19px; transform: rotate(8deg); }\n    .ols-csg-precipitation .ols-csg-precipitate {\n      left: 48px;\n      bottom: 10px;\n      width: 54px;\n      height: 18px;\n      border-radius: 999px 999px 12px 12px;\n      background: rgba(201,151,58,0.70);\n      box-shadow: 0 9px 18px rgba(201,151,58,0.20);\n    }\n\n    .ols-csg-precipitation .ols-csg-arrow { left: 62px; top: 33px; width: 26px; height: 3px; border-radius: 999px; background: rgba(201, 151, 58, 0.88); transform: rotate(90deg); }\n    .ols-csg-precipitation .ols-csg-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    .ols-csg-precipitation .ols-csg-label-mini { left: 48px; top: 7px; color: var(--blue); font-size: 12px; font-weight: 800; }\n\n\n    .ols-csg-molar .ols-csg-tube {\n      position: absolute;\n      left: 53px;\n      top: 8px;\n      width: 46px;\n      height: 78px;\n      border: 4px solid rgba(28, 36, 75, 0.70);\n      border-top: none;\n      border-radius: 0 0 23px 23px;\n      background: linear-gradient(180deg, rgba(238,244,255,0) 34%, rgba(238,244,255,0.95) 35%, rgba(238,244,255,0.95) 100%);\n    }\n\n    .ols-csg-molar .ols-csg-bubble {\n      width: 16px;\n      height: 16px;\n      border-radius: 50%;\n      border: 3px solid rgba(37, 99, 235, 0.72);\n      background: rgba(238, 244, 255, 0.82);\n      box-shadow: 0 7px 16px rgba(37, 99, 235, 0.12);\n    }\n\n    .ols-csg-molar .g1 { left: 33px; top: 50px; }\n    .ols-csg-molar .g2 { left: 83px; top: 38px; transform: scale(0.84); }\n    .ols-csg-molar .g3 { left: 99px; top: 16px; transform: scale(0.66); }\n    .ols-csg-molar .ols-csg-label-mini { left: 9px; top: 8px; color: var(--gold); font-size: 13px; font-weight: 800; }\n\n    .ols-csg-solution .ols-csg-flask {\n      left: 31px;\n      bottom: 7px;\n      width: 88px;\n      height: 50px;\n      border: 4px solid rgba(28, 36, 75, 0.70);\n      border-top: none;\n      border-radius: 9px 9px 30px 30px;\n      background: linear-gradient(180deg, rgba(238,244,255,0) 28%, rgba(37,99,235,0.18) 29%, rgba(37,99,235,0.18) 100%);\n    }\n\n    .ols-csg-solution .ols-csg-neck {\n      left: 64px;\n      top: 6px;\n      width: 22px;\n      height: 36px;\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-csg-solution .ols-csg-dot {\n      width: 12px;\n      height: 12px;\n      border-radius: 50%;\n      background: var(--blue);\n      opacity: 0.78;\n    }\n\n    .ols-csg-solution .s1 { left: 45px; top: 58px; }\n    .ols-csg-solution .s2 { left: 71px; top: 68px; transform: scale(0.82); }\n    .ols-csg-solution .s3 { left: 95px; top: 55px; transform: scale(0.72); }\n    .ols-csg-solution .ols-csg-label-mini { right: 6px; top: 8px; color: var(--blue); font-size: 13px; font-weight: 800; }\n\n    .ols-csg-ppm .ols-csg-box {\n      width: 31px;\n      height: 31px;\n      border-radius: 10px;\n      display: grid;\n      place-items: center;\n      color: #ffffff;\n      font-size: 12px;\n      font-weight: 800;\n      box-shadow: 0 8px 18px rgba(28, 36, 75, 0.16);\n    }\n\n    .ols-csg-ppm .p1 { left: 8px; top: 14px; background: var(--blue); }\n    .ols-csg-ppm .p2 { left: 47px; top: 14px; background: var(--navy); }\n    .ols-csg-ppm .p3 { left: 86px; top: 14px; background: var(--gold); }\n    .ols-csg-ppm .p4 { left: 125px; top: 14px; background: #c81e1e; }\n    .ols-csg-ppm .ols-csg-line { left: 9px; right: 9px; bottom: 25px; height: 4px; border-radius: 999px; background: rgba(28, 36, 75, 0.22); }\n    .ols-csg-ppm .ols-csg-label-mini { left: 38px; bottom: 5px; color: var(--gold); font-size: 15px; font-weight: 800; }\n\n    .ols-csg-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-csg-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-csg-card,\n    .ols-csg-card *,\n    .ols-csg-card:hover,\n    .ols-csg-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-csg-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-csg-card:hover .ols-csg-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-sidebar { position: relative; top: auto; }\n      .ols-topic-list { grid-template-columns: repeat(2, minmax(0, 1fr)); }\n      .ols-subtopic-list { 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-topic-list, .ols-csg-grid, .ols-related-grid { grid-template-columns: 1fr; }\n      .ols-subtopic-list { margin-left: 8px; }\n      .ols-author { align-items: flex-start; padding: 22px 18px; border-radius: 22px; }\n      .ols-author-avatar-img { width: 72px; height: 72px; }\n      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href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-3-amount-of-substance\/\">Section overview<\/a><\/li>\n      <li><a 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><\/li>\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-3-amount-of-substance\/mole-calculations\/\">Mole Calculations<\/a>\n        <ul class=\"ols-subtopic-list\">\n          <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-3-amount-of-substance\/mole-calculations\/comparing-masses-of-substances\/\">Comparing Masses of Substances<\/a><\/li>\n          <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-3-amount-of-substance\/mole-calculations\/calculations-involving-moles\/\">Calculations involving Moles<\/a><\/li>\n          <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-3-amount-of-substance\/mole-calculations\/calculations-using-reacting-masses\/\">Calculations using Reacting Masses<\/a><\/li>\n          <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-3-amount-of-substance\/mole-calculations\/the-yield-of-a-reaction\/\">The Yield of a Reaction<\/a><\/li>\n          <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-3-amount-of-substance\/mole-calculations\/atom-economy\/\">Atom Economy<\/a><\/li>\n        <\/ul>\n      <\/li>\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-3-amount-of-substance\/empirical-and-molecular-formulae\/\">Empirical and Molecular Formulae<\/a>\n        <ul class=\"ols-subtopic-list\">\n          <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-3-amount-of-substance\/empirical-and-molecular-formulae\/empirical-formulae\/\">Empirical Formulae<\/a><\/li>\n          <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-3-amount-of-substance\/empirical-and-molecular-formulae\/molecular-formulae\/\">Molecular Formulae<\/a><\/li>\n        <\/ul>\n      <\/li>\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-3-amount-of-substance\/calculations-with-solutions-and-gases\/\">Calculations with Solutions and Gases<\/a>\n        <ul class=\"ols-subtopic-list\">\n          <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-3-amount-of-substance\/calculations-with-solutions-and-gases\/molar-volume-calculations\/\">Molar Volume Calculations<\/a><\/li>\n          <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-3-amount-of-substance\/calculations-with-solutions-and-gases\/concentrations-of-solutions\/\">Concentrations of Solutions<\/a><\/li>\n<li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-3-amount-of-substance\/hydrated-salts-and-water-of-crystallisation\/\">Hydrated Salts and Water of Crystallisation<\/a><\/li>\n<li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-3-amount-of-substance\/measuring-mass-volume-and-gas-volume\/\">Measuring Mass, Volume and Gas Volume<\/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\/2-1-2-compounds-formulae-and-equations\/\">2.1.2 Compounds, Formulae and Equations<\/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 = 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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\/ocr-a\/\">OCR A<\/a> \/\n<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> \/\n<span>Calculations with Solutions and Gases<\/span>\n<\/nav>\n\n      <header class=\"ols-title-card\">\n        <h1>Calculations with Solutions and Gases<\/h1>\n        <p class=\"ols-page-intro\">Use this landing page to move quickly between the key quantitative chemistry pages for solutions and gases in OCR. Each card links to a focused page covering molar volume calculations, solution concentration calculations and titration calculations.<\/p>\n\n        <div class=\"ols-badges\">\n<div class=\"ols-badge\">Paper 1 and 2<\/div>\n<div class=\"ols-badge\">2.1.3 Amount of Substance<\/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 a Calculations with Solutions and Gases Page<\/h2>\n        <\/div>\n\n        <p>Calculations with solutions and gases connect the mole concept to measurable laboratory quantities. These pages build from calculating gas volumes, through using concentration in mol dm<sup>\u22123<\/sup>, to interpreting very small concentrations expressed in parts per million.<\/p>\n\n        <div class=\"ols-key-box\">\n          <p><strong>Key idea:<\/strong> Quantitative chemistry depends on choosing the correct relationship between amount of substance, volume, concentration and mass, then keeping units consistent throughout the calculation.<\/p>\n        <\/div>\n\n        <div class=\"ols-csg-grid\">\n          <a class=\"ols-csg-card ols-csg-card--available\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-3-amount-of-substance\/calculations-with-solutions-and-gases\/molar-volume-calculations\/\">\n            <div class=\"ols-csg-card-img-wrap\">\n              <div class=\"ols-csg-visual ols-csg-visual--gas\">\n                <div class=\"ols-csg-visual-panel\">\n                  <div class=\"ols-csg-visual-kicker\">Gas volume<\/div>\n                  <div class=\"ols-csg-simple-symbol\" aria-hidden=\"true\">V = n \u00d7 24<\/div>\n                  <div class=\"ols-csg-visual-main\">Molar<br>Volume<\/div>\n                  <div class=\"ols-csg-visual-sub\">gas volume and amount in moles<\/div>\n                <\/div>\n              <\/div>\n              <div class=\"ols-csg-card-num\">1<\/div>\n              <span class=\"ols-csg-card-status\">Available<\/span>\n            <\/div>\n            <div class=\"ols-csg-card-body\">\n              <h3>Molar Volume Calculations<\/h3>\n              <p>Revise how the amount of gas in moles links to gas volume, including the use of molar gas volume in calculations.<\/p>\n              <span class=\"ols-csg-meta\">Start revising<\/span>\n            <\/div>\n          <\/a>\n\n          <a class=\"ols-csg-card ols-csg-card--available\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-3-amount-of-substance\/calculations-with-solutions-and-gases\/concentrations-of-solutions\/\">\n            <div class=\"ols-csg-card-img-wrap\">\n              <div class=\"ols-csg-visual ols-csg-visual--solution\">\n                <div class=\"ols-csg-visual-panel\">\n                  <div class=\"ols-csg-visual-kicker\">Solution concentration<\/div>\n                  <div class=\"ols-csg-simple-symbol\" aria-hidden=\"true\">c = n\/V<\/div>\n                  <div class=\"ols-csg-visual-main\">Solution<br>Concentration<\/div>\n                  <div class=\"ols-csg-visual-sub\">amount, volume and concentration<\/div>\n                <\/div>\n              <\/div>\n              <div class=\"ols-csg-card-num\">2<\/div>\n              <span class=\"ols-csg-card-status\">Available<\/span>\n            <\/div>\n            <div class=\"ols-csg-card-body\">\n              <h3>Concentrations of Solutions<\/h3>\n              <p>Practise using concentration, volume and amount of substance in mol dm<sup>\u22123<\/sup> calculations.<\/p>\n              <span class=\"ols-csg-meta\">Start revising<\/span>\n            <\/div>\n          <\/a>\n\n          <a class=\"ols-csg-card ols-csg-card--available\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-4-acids\/titration-calculations\/\">\n            <div class=\"ols-csg-card-img-wrap\">\n              <div class=\"ols-csg-visual ols-csg-visual--titration\">\n                <div class=\"ols-csg-visual-panel\">\n                  <div class=\"ols-csg-visual-kicker\">Volumetric analysis<\/div>\n                  <div class=\"ols-csg-simple-symbol\" aria-hidden=\"true\">cV<\/div>\n                  <div class=\"ols-csg-visual-main\">Titration<br>Calculations<\/div>\n                  <div class=\"ols-csg-visual-sub\">concentration, volume and mole ratios<\/div>\n                <\/div>\n              <\/div>\n              <div class=\"ols-csg-card-num\">3<\/div>\n              <span class=\"ols-csg-card-status\">Available<\/span>\n            <\/div>\n            <div class=\"ols-csg-card-body\">\n              <h3>Titration Calculations<\/h3>\n              <p>Use concentration, volume and balanced equation ratios to calculate unknown concentrations from titration data.<\/p>\n              <span class=\"ols-csg-meta\">Start revising<\/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 molar volume calculations to link gases to amount of substance. Then move to concentrations of solutions, because many titration and practical chemistry questions require confident use of concentration and volume. Finally, use the titration calculations page to connect solution concentration with reacting mole ratios and practical volumetric analysis.<\/p>\n\n        <div class=\"ols-key-box\">\n          <p><strong>Exam focus:<\/strong> Always check units before substituting numbers. Volumes may need converting between cm<sup>3<\/sup> and dm<sup>3<\/sup>, and titration calculations usually require the balanced equation ratio before finding the unknown concentration.<\/p>\n        <\/div>\n      <\/article>\n\n\n\n      <section class=\"ols-related-card\">\n        <h2>Related Pages<\/h2>\n        <p>Use these pages to connect calculations with solutions and gases to mole calculations, empirical formulae, equations and amount of substance revision.<\/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\/mole-calculations\/\">Mole Calculations<\/a>\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\/mole-calculations\/calculations-involving-moles\/\">Calculations involving Moles<\/a>\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\/mole-calculations\/calculations-using-reacting-masses\/\">Calculations using Reacting Masses<\/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\/\">Equations and Reaction Types<\/a>\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\/empirical-and-molecular-formulae\/\">Empirical and Molecular Formulae<\/a>\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\/\">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\/2-1-3-amount-of-substance\/calculations-with-solutions-and-gases\/#webpage\",\n      \"url\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-3-amount-of-substance\/calculations-with-solutions-and-gases\/\",\n      \"name\": \"Calculations with Solutions and Gases - OCR A Level Chemistry A\",\n      \"description\": \"OCR A Level Chemistry A this section landing page for calculations with solutions and gases, including molar volume calculations, concentrations of solutions and titration calculations.\",\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\": \"Molar volume calculations\"\n        },\n        {\n          \"@type\": \"Thing\",\n          \"name\": \"Concentrations of solutions\"\n        },\n        {\n          \"@type\": \"Thing\",\n          \"name\": \"Titration calculations\"\n        },\n        {\n          \"@type\": \"Thing\",\n          \"name\": \"Amount of substance calculations\"\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\/2-1-3-amount-of-substance\/calculations-with-solutions-and-gases\/#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\": \"2.1.3 Amount of Substance\",\n          \"item\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-3-amount-of-substance\/\"\n        },\n        {\n          \"@type\": \"ListItem\",\n          \"position\": 5,\n          \"name\": \"Calculations with Solutions and Gases\",\n          \"item\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/ocr-a\/2-1-3-amount-of-substance\/calculations-with-solutions-and-gases\/\"\n        }\n      ]\n    }\n  ]\n}\n<\/script>\n    <\/main>\n<\/section>\n","protected":false},"excerpt":{"rendered":"<p>Revision Notes \/ A Level Chemistry \/ OCR A \/ 2.1.3 Amount of Substance \/ Calculations with Solutions and Gases Calculations with Solutions and Gases Use this landing page to move quickly between the key quantitative chemistry pages for solutions and gases in OCR. 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