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vector-toc-pinnable-header vector-pinnable-header-pinned" data-feature-name="toc-pinned" data-pinnable-element-id="vector-toc" > <h2 class="vector-pinnable-header-label">Indice</h2> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-toc.pin">sposta nella barra laterale</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-toc.unpin">nascondi</button> </div> <ul class="vector-toc-contents" id="mw-panel-toc-list"> <li id="toc-mw-content-text" class="vector-toc-list-item vector-toc-level-1"> <a href="#" class="vector-toc-link"> <div class="vector-toc-text">Inizio</div> </a> </li> <li id="toc-Calcolo" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Calcolo"> <div class="vector-toc-text"> <span class="vector-toc-numb">1</span> <span>Calcolo</span> </div> </a> <ul id="toc-Calcolo-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Valori_tipici" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Valori_tipici"> <div class="vector-toc-text"> <span class="vector-toc-numb">2</span> <span>Valori tipici</span> </div> </a> <ul id="toc-Valori_tipici-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Peso_formula" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Peso_formula"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>Peso formula</span> </div> </a> <ul id="toc-Peso_formula-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Tipi_di_massa_molecolare" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Tipi_di_massa_molecolare"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>Tipi di massa molecolare</span> </div> </a> <ul id="toc-Tipi_di_massa_molecolare-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Miscele" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Miscele"> <div class="vector-toc-text"> <span class="vector-toc-numb">5</span> <span>Miscele</span> </div> </a> <ul id="toc-Miscele-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Massa_molecolare_e_relatività_speciale" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Massa_molecolare_e_relatività_speciale"> <div class="vector-toc-text"> <span class="vector-toc-numb">6</span> <span>Massa molecolare e relatività speciale</span> </div> </a> <ul id="toc-Massa_molecolare_e_relatività_speciale-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Note" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Note"> <div class="vector-toc-text"> <span class="vector-toc-numb">7</span> <span>Note</span> </div> </a> <ul id="toc-Note-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Voci_correlate" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Voci_correlate"> <div class="vector-toc-text"> <span class="vector-toc-numb">8</span> <span>Voci correlate</span> </div> </a> <ul id="toc-Voci_correlate-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Collegamenti_esterni" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Collegamenti_esterni"> <div class="vector-toc-text"> <span class="vector-toc-numb">9</span> <span>Collegamenti esterni</span> </div> </a> <ul id="toc-Collegamenti_esterni-sublist" class="vector-toc-list"> </ul> </li> </ul> </div> </div> </nav> </div> </div> <div class="mw-content-container"> <main id="content" class="mw-body"> <header class="mw-body-header vector-page-titlebar"> <nav aria-label="Indice" class="vector-toc-landmark"> <div id="vector-page-titlebar-toc" class="vector-dropdown vector-page-titlebar-toc vector-button-flush-left" title="Indice" > <input type="checkbox" id="vector-page-titlebar-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-titlebar-toc" class="vector-dropdown-checkbox " aria-label="Mostra/Nascondi l'indice" > <label id="vector-page-titlebar-toc-label" for="vector-page-titlebar-toc-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-listBullet mw-ui-icon-wikimedia-listBullet"></span> <span class="vector-dropdown-label-text">Mostra/Nascondi l'indice</span> </label> <div class="vector-dropdown-content"> <div id="vector-page-titlebar-toc-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <h1 id="firstHeading" class="firstHeading mw-first-heading"><span class="mw-page-title-main">Massa molecolare</span></h1> <div id="p-lang-btn" class="vector-dropdown mw-portlet mw-portlet-lang" > <input type="checkbox" id="p-lang-btn-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-p-lang-btn" class="vector-dropdown-checkbox mw-interlanguage-selector" aria-label="Vai a una voce in un'altra lingua. Disponibile in 62 lingue" > <label id="p-lang-btn-label" for="p-lang-btn-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive mw-portlet-lang-heading-62" aria-hidden="true" ><span class="vector-icon mw-ui-icon-language-progressive mw-ui-icon-wikimedia-language-progressive"></span> <span class="vector-dropdown-label-text">62 lingue</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D9%83%D8%AA%D9%84%D8%A9_%D8%AC%D8%B2%D9%8A%D8%A6%D9%8A%D8%A9" title="كتلة جزيئية - arabo" lang="ar" hreflang="ar" data-title="كتلة جزيئية" data-language-autonym="العربية" data-language-local-name="arabo" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-be mw-list-item"><a href="https://be.wikipedia.org/wiki/%D0%90%D0%B4%D0%BD%D0%BE%D1%81%D0%BD%D0%B0%D1%8F_%D0%BC%D0%B0%D0%BB%D0%B5%D0%BA%D1%83%D0%BB%D1%8F%D1%80%D0%BD%D0%B0%D1%8F_%D0%BC%D0%B0%D1%81%D0%B0" title="Адносная малекулярная маса - bielorusso" lang="be" hreflang="be" data-title="Адносная малекулярная маса" data-language-autonym="Беларуская" data-language-local-name="bielorusso" class="interlanguage-link-target"><span>Беларуская</span></a></li><li class="interlanguage-link interwiki-be-x-old mw-list-item"><a href="https://be-tarask.wikipedia.org/wiki/%D0%90%D0%B4%D0%BD%D0%BE%D1%81%D0%BD%D0%B0%D1%8F_%D0%BC%D0%B0%D0%BB%D0%B5%D0%BA%D1%83%D0%BB%D1%8F%D1%80%D0%BD%D0%B0%D1%8F_%D0%BC%D0%B0%D1%81%D0%B0" title="Адносная малекулярная маса - Belarusian (Taraškievica orthography)" lang="be-tarask" hreflang="be-tarask" data-title="Адносная малекулярная маса" data-language-autonym="Беларуская (тарашкевіца)" data-language-local-name="Belarusian (Taraškievica orthography)" class="interlanguage-link-target"><span>Беларуская (тарашкевіца)</span></a></li><li class="interlanguage-link interwiki-bg mw-list-item"><a href="https://bg.wikipedia.org/wiki/%D0%9C%D0%BE%D0%BB%D0%B5%D0%BA%D1%83%D0%BB%D0%BD%D0%B0_%D0%BC%D0%B0%D1%81%D0%B0" title="Молекулна маса - bulgaro" lang="bg" hreflang="bg" data-title="Молекулна маса" data-language-autonym="Български" data-language-local-name="bulgaro" class="interlanguage-link-target"><span>Български</span></a></li><li class="interlanguage-link interwiki-bn mw-list-item"><a href="https://bn.wikipedia.org/wiki/%E0%A6%86%E0%A6%A3%E0%A6%AC%E0%A6%BF%E0%A6%95_%E0%A6%AD%E0%A6%B0" title="আণবিক ভর - bengalese" lang="bn" hreflang="bn" data-title="আণবিক ভর" data-language-autonym="বাংলা" data-language-local-name="bengalese" class="interlanguage-link-target"><span>বাংলা</span></a></li><li class="interlanguage-link interwiki-br mw-list-item"><a href="https://br.wikipedia.org/wiki/Tolz_molekulel" title="Tolz molekulel - bretone" lang="br" hreflang="br" data-title="Tolz molekulel" data-language-autonym="Brezhoneg" data-language-local-name="bretone" class="interlanguage-link-target"><span>Brezhoneg</span></a></li><li class="interlanguage-link interwiki-bs mw-list-item"><a href="https://bs.wikipedia.org/wiki/Molekulska_masa" title="Molekulska masa - bosniaco" lang="bs" hreflang="bs" data-title="Molekulska masa" data-language-autonym="Bosanski" data-language-local-name="bosniaco" class="interlanguage-link-target"><span>Bosanski</span></a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/Massa_molecular" title="Massa molecular - catalano" lang="ca" hreflang="ca" data-title="Massa molecular" data-language-autonym="Català" data-language-local-name="catalano" class="interlanguage-link-target"><span>Català</span></a></li><li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/Molek%C3%BClmasse" title="Molekülmasse - tedesco" lang="de" hreflang="de" data-title="Molekülmasse" data-language-autonym="Deutsch" data-language-local-name="tedesco" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-el mw-list-item"><a href="https://el.wikipedia.org/wiki/%CE%9C%CE%BF%CF%81%CE%B9%CE%B1%CE%BA%CF%8C_%CE%B2%CE%AC%CF%81%CE%BF%CF%82" title="Μοριακό βάρος - greco" lang="el" hreflang="el" data-title="Μοριακό βάρος" data-language-autonym="Ελληνικά" data-language-local-name="greco" class="interlanguage-link-target"><span>Ελληνικά</span></a></li><li class="interlanguage-link interwiki-en mw-list-item"><a href="https://en.wikipedia.org/wiki/Molecular_mass" title="Molecular mass - inglese" lang="en" hreflang="en" data-title="Molecular mass" data-language-autonym="English" data-language-local-name="inglese" class="interlanguage-link-target"><span>English</span></a></li><li class="interlanguage-link interwiki-eo mw-list-item"><a href="https://eo.wikipedia.org/wiki/Molekula_maso" title="Molekula maso - esperanto" lang="eo" hreflang="eo" data-title="Molekula maso" data-language-autonym="Esperanto" data-language-local-name="esperanto" class="interlanguage-link-target"><span>Esperanto</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Masa_molecular" title="Masa molecular - spagnolo" lang="es" hreflang="es" data-title="Masa molecular" data-language-autonym="Español" data-language-local-name="spagnolo" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-et mw-list-item"><a href="https://et.wikipedia.org/wiki/Molekulmass" title="Molekulmass - estone" lang="et" hreflang="et" data-title="Molekulmass" data-language-autonym="Eesti" data-language-local-name="estone" class="interlanguage-link-target"><span>Eesti</span></a></li><li class="interlanguage-link interwiki-eu mw-list-item"><a href="https://eu.wikipedia.org/wiki/Masa_molekular" title="Masa molekular - basco" lang="eu" hreflang="eu" data-title="Masa molekular" data-language-autonym="Euskara" data-language-local-name="basco" class="interlanguage-link-target"><span>Euskara</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D8%AC%D8%B1%D9%85_%D9%85%D9%88%D9%84%DA%A9%D9%88%D9%84%DB%8C" title="جرم مولکولی - persiano" lang="fa" hreflang="fa" data-title="جرم مولکولی" data-language-autonym="فارسی" data-language-local-name="persiano" class="interlanguage-link-target"><span>فارسی</span></a></li><li class="interlanguage-link interwiki-fi mw-list-item"><a href="https://fi.wikipedia.org/wiki/Molekyylimassa" title="Molekyylimassa - finlandese" lang="fi" hreflang="fi" data-title="Molekyylimassa" data-language-autonym="Suomi" data-language-local-name="finlandese" class="interlanguage-link-target"><span>Suomi</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/Masse_mol%C3%A9culaire" title="Masse moléculaire - francese" lang="fr" hreflang="fr" data-title="Masse moléculaire" data-language-autonym="Français" data-language-local-name="francese" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-ga mw-list-item"><a href="https://ga.wikipedia.org/wiki/Mais_mh%C3%B3il%C3%ADneach" title="Mais mhóilíneach - irlandese" lang="ga" hreflang="ga" data-title="Mais mhóilíneach" data-language-autonym="Gaeilge" data-language-local-name="irlandese" class="interlanguage-link-target"><span>Gaeilge</span></a></li><li class="interlanguage-link interwiki-gl mw-list-item"><a href="https://gl.wikipedia.org/wiki/Masa_molecular" title="Masa molecular - galiziano" lang="gl" hreflang="gl" data-title="Masa molecular" data-language-autonym="Galego" data-language-local-name="galiziano" class="interlanguage-link-target"><span>Galego</span></a></li><li class="interlanguage-link interwiki-he mw-list-item"><a href="https://he.wikipedia.org/wiki/%D7%9E%D7%A1%D7%94_%D7%9E%D7%95%D7%9C%D7%A7%D7%95%D7%9C%D7%A8%D7%99%D7%AA" title="מסה מולקולרית - ebraico" lang="he" hreflang="he" data-title="מסה מולקולרית" data-language-autonym="עברית" data-language-local-name="ebraico" class="interlanguage-link-target"><span>עברית</span></a></li><li class="interlanguage-link interwiki-hi mw-list-item"><a href="https://hi.wikipedia.org/wiki/%E0%A4%85%E0%A4%A3%E0%A5%81_%E0%A4%AD%E0%A4%BE%E0%A4%B0" title="अणु भार - hindi" lang="hi" hreflang="hi" data-title="अणु भार" data-language-autonym="हिन्दी" data-language-local-name="hindi" class="interlanguage-link-target"><span>हिन्दी</span></a></li><li class="interlanguage-link interwiki-hr mw-list-item"><a href="https://hr.wikipedia.org/wiki/Relativna_molekulska_masa" title="Relativna molekulska masa - croato" lang="hr" hreflang="hr" data-title="Relativna molekulska masa" data-language-autonym="Hrvatski" data-language-local-name="croato" class="interlanguage-link-target"><span>Hrvatski</span></a></li><li class="interlanguage-link interwiki-hu mw-list-item"><a href="https://hu.wikipedia.org/wiki/Molekulat%C3%B6meg" title="Molekulatömeg - ungherese" lang="hu" hreflang="hu" data-title="Molekulatömeg" data-language-autonym="Magyar" data-language-local-name="ungherese" class="interlanguage-link-target"><span>Magyar</span></a></li><li class="interlanguage-link interwiki-hy mw-list-item"><a href="https://hy.wikipedia.org/wiki/%D5%84%D5%B8%D5%AC%D5%A5%D5%AF%D5%B8%D6%82%D5%AC%D5%A1%D5%B5%D5%AB%D5%B6_%D5%A6%D5%A1%D5%B6%D5%A3%D5%BE%D5%A1%D5%AE" title="Մոլեկուլային զանգված - armeno" lang="hy" hreflang="hy" data-title="Մոլեկուլային զանգված" data-language-autonym="Հայերեն" data-language-local-name="armeno" class="interlanguage-link-target"><span>Հայերեն</span></a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Massa_molekul_relatif" title="Massa molekul relatif - indonesiano" lang="id" hreflang="id" data-title="Massa molekul relatif" data-language-autonym="Bahasa Indonesia" data-language-local-name="indonesiano" class="interlanguage-link-target"><span>Bahasa Indonesia</span></a></li><li class="interlanguage-link interwiki-is mw-list-item"><a href="https://is.wikipedia.org/wiki/Sameindamassi" title="Sameindamassi - islandese" lang="is" hreflang="is" data-title="Sameindamassi" data-language-autonym="Íslenska" data-language-local-name="islandese" class="interlanguage-link-target"><span>Íslenska</span></a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/%E5%88%86%E5%AD%90%E9%87%8F" title="分子量 - giapponese" lang="ja" hreflang="ja" data-title="分子量" data-language-autonym="日本語" data-language-local-name="giapponese" class="interlanguage-link-target"><span>日本語</span></a></li><li class="interlanguage-link interwiki-ka mw-list-item"><a href="https://ka.wikipedia.org/wiki/%E1%83%9B%E1%83%9D%E1%83%9A%E1%83%94%E1%83%99%E1%83%A3%E1%83%9A%E1%83%A3%E1%83%A0%E1%83%98_%E1%83%9B%E1%83%90%E1%83%A1%E1%83%90" title="მოლეკულური მასა - georgiano" lang="ka" hreflang="ka" data-title="მოლეკულური მასა" data-language-autonym="ქართული" data-language-local-name="georgiano" class="interlanguage-link-target"><span>ქართული</span></a></li><li class="interlanguage-link interwiki-kab mw-list-item"><a href="https://kab.wikipedia.org/wiki/Takura_tacubrant" title="Takura tacubrant - cabilo" lang="kab" hreflang="kab" data-title="Takura tacubrant" data-language-autonym="Taqbaylit" data-language-local-name="cabilo" class="interlanguage-link-target"><span>Taqbaylit</span></a></li><li class="interlanguage-link interwiki-kn mw-list-item"><a href="https://kn.wikipedia.org/wiki/%E0%B2%85%E0%B2%A3%E0%B3%81%E0%B2%A4%E0%B3%82%E0%B2%95" title="ಅಣುತೂಕ - kannada" lang="kn" hreflang="kn" data-title="ಅಣುತೂಕ" data-language-autonym="ಕನ್ನಡ" data-language-local-name="kannada" class="interlanguage-link-target"><span>ಕನ್ನಡ</span></a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%EB%B6%84%EC%9E%90%EB%9F%89" title="분자량 - coreano" lang="ko" hreflang="ko" data-title="분자량" data-language-autonym="한국어" data-language-local-name="coreano" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-ky mw-list-item"><a href="https://ky.wikipedia.org/wiki/%D0%9C%D0%BE%D0%BB%D0%B5%D0%BA%D1%83%D0%BB%D0%B0%D0%BB%D1%8B%D0%BA_%D0%BC%D0%B0%D1%81%D1%81%D0%B0" title="Молекулалык масса - kirghiso" lang="ky" hreflang="ky" data-title="Молекулалык масса" data-language-autonym="Кыргызча" data-language-local-name="kirghiso" class="interlanguage-link-target"><span>Кыргызча</span></a></li><li class="interlanguage-link interwiki-lmo mw-list-item"><a href="https://lmo.wikipedia.org/wiki/Massa_muleculara" title="Massa muleculara - lombardo" lang="lmo" hreflang="lmo" data-title="Massa muleculara" data-language-autonym="Lombard" data-language-local-name="lombardo" class="interlanguage-link-target"><span>Lombard</span></a></li><li class="interlanguage-link interwiki-lt mw-list-item"><a href="https://lt.wikipedia.org/wiki/Molekulin%C4%97_mas%C4%97" title="Molekulinė masė - lituano" lang="lt" hreflang="lt" data-title="Molekulinė masė" data-language-autonym="Lietuvių" data-language-local-name="lituano" class="interlanguage-link-target"><span>Lietuvių</span></a></li><li class="interlanguage-link interwiki-lv mw-list-item"><a href="https://lv.wikipedia.org/wiki/Molekulu_masa" title="Molekulu masa - lettone" lang="lv" hreflang="lv" data-title="Molekulu masa" data-language-autonym="Latviešu" data-language-local-name="lettone" class="interlanguage-link-target"><span>Latviešu</span></a></li><li class="interlanguage-link interwiki-mk mw-list-item"><a href="https://mk.wikipedia.org/wiki/%D0%9C%D0%BE%D0%BB%D0%B5%D0%BA%D1%83%D0%BB%D1%81%D0%BA%D0%B0_%D0%BC%D0%B0%D1%81%D0%B0" title="Молекулска маса - macedone" lang="mk" hreflang="mk" data-title="Молекулска маса" data-language-autonym="Македонски" data-language-local-name="macedone" class="interlanguage-link-target"><span>Македонски</span></a></li><li class="interlanguage-link interwiki-mr mw-list-item"><a href="https://mr.wikipedia.org/wiki/%E0%A4%B0%E0%A5%87%E0%A4%A3%E0%A5%81%E0%A4%AD%E0%A4%BE%E0%A4%B0" title="रेणुभार - marathi" lang="mr" hreflang="mr" data-title="रेणुभार" data-language-autonym="मराठी" data-language-local-name="marathi" class="interlanguage-link-target"><span>मराठी</span></a></li><li class="interlanguage-link interwiki-ms mw-list-item"><a href="https://ms.wikipedia.org/wiki/Jisim_molekul" title="Jisim molekul - malese" lang="ms" hreflang="ms" data-title="Jisim molekul" data-language-autonym="Bahasa Melayu" data-language-local-name="malese" class="interlanguage-link-target"><span>Bahasa Melayu</span></a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Moleculaire_massa" title="Moleculaire massa - olandese" lang="nl" hreflang="nl" data-title="Moleculaire massa" data-language-autonym="Nederlands" data-language-local-name="olandese" class="interlanguage-link-target"><span>Nederlands</span></a></li><li class="interlanguage-link interwiki-nn mw-list-item"><a href="https://nn.wikipedia.org/wiki/Molekylmasse" title="Molekylmasse - norvegese nynorsk" lang="nn" hreflang="nn" data-title="Molekylmasse" data-language-autonym="Norsk nynorsk" data-language-local-name="norvegese nynorsk" class="interlanguage-link-target"><span>Norsk nynorsk</span></a></li><li class="interlanguage-link interwiki-oc mw-list-item"><a href="https://oc.wikipedia.org/wiki/Massa_moleculara" title="Massa moleculara - occitano" lang="oc" hreflang="oc" data-title="Massa moleculara" data-language-autonym="Occitan" data-language-local-name="occitano" class="interlanguage-link-target"><span>Occitan</span></a></li><li class="interlanguage-link interwiki-pa mw-list-item"><a href="https://pa.wikipedia.org/wiki/%E0%A8%85%E0%A8%A3%E0%A8%B5%E0%A9%80_%E0%A8%AD%E0%A8%BE%E0%A8%B0" title="ਅਣਵੀ ਭਾਰ - punjabi" lang="pa" hreflang="pa" data-title="ਅਣਵੀ ਭਾਰ" data-language-autonym="ਪੰਜਾਬੀ" data-language-local-name="punjabi" class="interlanguage-link-target"><span>ਪੰਜਾਬੀ</span></a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Masa_cz%C4%85steczkowa" title="Masa cząsteczkowa - polacco" lang="pl" hreflang="pl" data-title="Masa cząsteczkowa" data-language-autonym="Polski" data-language-local-name="polacco" class="interlanguage-link-target"><span>Polski</span></a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/Massa_molecular" title="Massa molecular - portoghese" lang="pt" hreflang="pt" data-title="Massa molecular" data-language-autonym="Português" data-language-local-name="portoghese" class="interlanguage-link-target"><span>Português</span></a></li><li class="interlanguage-link interwiki-ro mw-list-item"><a href="https://ro.wikipedia.org/wiki/Mas%C4%83_molecular%C4%83" title="Masă moleculară - rumeno" lang="ro" hreflang="ro" data-title="Masă moleculară" data-language-autonym="Română" data-language-local-name="rumeno" class="interlanguage-link-target"><span>Română</span></a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/%D0%9C%D0%BE%D0%BB%D0%B5%D0%BA%D1%83%D0%BB%D1%8F%D1%80%D0%BD%D0%B0%D1%8F_%D0%BC%D0%B0%D1%81%D1%81%D0%B0" title="Молекулярная масса - russo" lang="ru" hreflang="ru" data-title="Молекулярная масса" data-language-autonym="Русский" data-language-local-name="russo" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-sh mw-list-item"><a href="https://sh.wikipedia.org/wiki/Molekulska_masa" title="Molekulska masa - serbo-croato" lang="sh" hreflang="sh" data-title="Molekulska masa" data-language-autonym="Srpskohrvatski / српскохрватски" data-language-local-name="serbo-croato" class="interlanguage-link-target"><span>Srpskohrvatski / српскохрватски</span></a></li><li class="interlanguage-link interwiki-simple mw-list-item"><a href="https://simple.wikipedia.org/wiki/Molecular_mass" title="Molecular mass - Simple English" lang="en-simple" hreflang="en-simple" data-title="Molecular mass" data-language-autonym="Simple English" data-language-local-name="Simple English" class="interlanguage-link-target"><span>Simple English</span></a></li><li class="interlanguage-link interwiki-sk mw-list-item"><a href="https://sk.wikipedia.org/wiki/Molekulov%C3%A1_hmotnos%C5%A5" title="Molekulová hmotnosť - slovacco" lang="sk" hreflang="sk" data-title="Molekulová hmotnosť" data-language-autonym="Slovenčina" data-language-local-name="slovacco" class="interlanguage-link-target"><span>Slovenčina</span></a></li><li class="interlanguage-link interwiki-sl mw-list-item"><a href="https://sl.wikipedia.org/wiki/Molekulska_masa" title="Molekulska masa - sloveno" lang="sl" hreflang="sl" data-title="Molekulska masa" data-language-autonym="Slovenščina" data-language-local-name="sloveno" class="interlanguage-link-target"><span>Slovenščina</span></a></li><li class="interlanguage-link interwiki-sr mw-list-item"><a href="https://sr.wikipedia.org/wiki/%D0%9C%D0%BE%D0%BB%D0%B5%D0%BA%D1%83%D0%BB%D1%81%D0%BA%D0%B0_%D0%BC%D0%B0%D1%81%D0%B0" title="Молекулска маса - serbo" lang="sr" hreflang="sr" data-title="Молекулска маса" data-language-autonym="Српски / srpski" data-language-local-name="serbo" class="interlanguage-link-target"><span>Српски / srpski</span></a></li><li class="interlanguage-link interwiki-su mw-list-item"><a href="https://su.wikipedia.org/wiki/Beurat_molekul" title="Beurat molekul - sundanese" lang="su" hreflang="su" data-title="Beurat molekul" data-language-autonym="Sunda" data-language-local-name="sundanese" class="interlanguage-link-target"><span>Sunda</span></a></li><li class="interlanguage-link interwiki-sv mw-list-item"><a href="https://sv.wikipedia.org/wiki/Molekylmassa" title="Molekylmassa - svedese" lang="sv" hreflang="sv" data-title="Molekylmassa" data-language-autonym="Svenska" data-language-local-name="svedese" class="interlanguage-link-target"><span>Svenska</span></a></li><li class="interlanguage-link interwiki-th mw-list-item"><a href="https://th.wikipedia.org/wiki/%E0%B8%A1%E0%B8%A7%E0%B8%A5%E0%B9%82%E0%B8%A1%E0%B9%80%E0%B8%A5%E0%B8%81%E0%B8%B8%E0%B8%A5" title="มวลโมเลกุล - thailandese" lang="th" hreflang="th" data-title="มวลโมเลกุล" data-language-autonym="ไทย" data-language-local-name="thailandese" class="interlanguage-link-target"><span>ไทย</span></a></li><li class="interlanguage-link interwiki-tr mw-list-item"><a href="https://tr.wikipedia.org/wiki/Molek%C3%BCl_k%C3%BCtlesi" title="Molekül kütlesi - turco" lang="tr" hreflang="tr" data-title="Molekül kütlesi" data-language-autonym="Türkçe" data-language-local-name="turco" class="interlanguage-link-target"><span>Türkçe</span></a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/%D0%9C%D0%BE%D0%BB%D0%B5%D0%BA%D1%83%D0%BB%D1%8F%D1%80%D0%BD%D0%B0_%D0%BC%D0%B0%D1%81%D0%B0" title="Молекулярна маса - ucraino" lang="uk" hreflang="uk" data-title="Молекулярна маса" data-language-autonym="Українська" data-language-local-name="ucraino" class="interlanguage-link-target"><span>Українська</span></a></li><li class="interlanguage-link interwiki-ur mw-list-item"><a href="https://ur.wikipedia.org/wiki/%D8%B3%D8%A7%D9%84%D9%85%DB%8C_%DA%A9%D9%85%DB%8C%D8%AA" title="سالمی کمیت - urdu" lang="ur" hreflang="ur" data-title="سالمی کمیت" data-language-autonym="اردو" data-language-local-name="urdu" class="interlanguage-link-target"><span>اردو</span></a></li><li class="interlanguage-link interwiki-vi mw-list-item"><a href="https://vi.wikipedia.org/wiki/Kh%E1%BB%91i_l%C6%B0%E1%BB%A3ng_ph%C3%A2n_t%E1%BB%AD" title="Khối lượng phân tử - vietnamita" lang="vi" hreflang="vi" data-title="Khối lượng phân tử" data-language-autonym="Tiếng Việt" data-language-local-name="vietnamita" class="interlanguage-link-target"><span>Tiếng Việt</span></a></li><li class="interlanguage-link interwiki-wuu mw-list-item"><a href="https://wuu.wikipedia.org/wiki/%E5%88%86%E5%AD%90%E9%87%8F" title="分子量 - wu" lang="wuu" hreflang="wuu" data-title="分子量" data-language-autonym="吴语" data-language-local-name="wu" class="interlanguage-link-target"><span>吴语</span></a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a href="https://zh.wikipedia.org/wiki/%E5%88%86%E5%AD%90%E9%87%8F" title="分子量 - cinese" lang="zh" hreflang="zh" data-title="分子量" data-language-autonym="中文" data-language-local-name="cinese" class="interlanguage-link-target"><span>中文</span></a></li><li class="interlanguage-link interwiki-zh-min-nan mw-list-item"><a href="https://zh-min-nan.wikipedia.org/wiki/Hun-ch%C3%BA-li%C5%8Dng" title="Hun-chú-liōng - min nan" lang="nan" hreflang="nan" data-title="Hun-chú-liōng" data-language-autonym="閩南語 / Bân-lâm-gú" data-language-local-name="min nan" class="interlanguage-link-target"><span>閩南語 / Bân-lâm-gú</span></a></li> </ul> <div class="after-portlet after-portlet-lang"><span class="wb-langlinks-edit wb-langlinks-link"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q182854#sitelinks-wikipedia" title="Modifica collegamenti interlinguistici" class="wbc-editpage">Modifica collegamenti</a></span></div> </div> </div> </div> </header> <div class="vector-page-toolbar"> <div class="vector-page-toolbar-container"> <div id="left-navigation"> <nav aria-label="Namespace"> <div id="p-associated-pages" class="vector-menu vector-menu-tabs mw-portlet mw-portlet-associated-pages" > <div class="vector-menu-content"> <ul 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Segui i suggerimenti del <a href="/wiki/Progetto:Chimica" title="Progetto:Chimica">progetto di riferimento</a>.</div> </div> </div> </div> </div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Relazione_tra_massa,_quantit%C3%A0_di_sostanza,_volume_e_numero_di_particelle.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/e/ed/Relazione_tra_massa%2C_quantit%C3%A0_di_sostanza%2C_volume_e_numero_di_particelle.svg/220px-Relazione_tra_massa%2C_quantit%C3%A0_di_sostanza%2C_volume_e_numero_di_particelle.svg.png" decoding="async" width="220" height="130" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/e/ed/Relazione_tra_massa%2C_quantit%C3%A0_di_sostanza%2C_volume_e_numero_di_particelle.svg/330px-Relazione_tra_massa%2C_quantit%C3%A0_di_sostanza%2C_volume_e_numero_di_particelle.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/e/ed/Relazione_tra_massa%2C_quantit%C3%A0_di_sostanza%2C_volume_e_numero_di_particelle.svg/440px-Relazione_tra_massa%2C_quantit%C3%A0_di_sostanza%2C_volume_e_numero_di_particelle.svg.png 2x" data-file-width="538" data-file-height="319" /></a><figcaption>La relazione tra massa, quantità di sostanza, volume e numero di particelle.</figcaption></figure> <p>La <b>massa molecolare</b> di una <a href="/wiki/Sostanza_chimica" class="mw-redirect" title="Sostanza chimica">sostanza</a> (detta pure impropriamente <b>peso molecolare</b>, che non differisce dalla <a href="/wiki/Massa_molare" title="Massa molare">massa molare</a> se non per l'unità di misura) è il rapporto tra la <a href="/wiki/Massa_(fisica)" title="Massa (fisica)">massa</a> di una data quantità di quella sostanza e il <a href="/wiki/Quantit%C3%A0_di_sostanza" title="Quantità di sostanza">numero di moli</a> della stessa quantità di quella sostanza. È comunemente espressa in <a href="/wiki/Unit%C3%A0_di_massa_atomica" title="Unità di massa atomica">unità di massa atomica</a> (u). In alcuni casi, per massa molecolare di una sostanza si intende il rapporto tra la massa di una data quantità di quella sostanza e il numero di entità elementari (ad esempio <a href="/wiki/Molecola" title="Molecola">molecole</a>) costituenti la stessa quantità di quella sostanza. La costante di conversione tra queste due interpretazioni della massa molecolare è la <a href="/wiki/Costante_di_Avogadro" title="Costante di Avogadro">costante di Avogadro</a>, ossia il numero di particelle elementari di una sostanza costituenti una mole di quella sostanza (per definizione di mole, la costante di Avogadro è la stessa per qualsiasi sostanza): </p> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\frac {m[g/N_{p}e]}{N_{A}}}=m[u]}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mrow> <mi>m</mi> <mo stretchy="false">[</mo> <mi>g</mi> <mrow class="MJX-TeXAtom-ORD"> <mo>/</mo> </mrow> <msub> <mi>N</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>p</mi> </mrow> </msub> <mi>e</mi> <mo stretchy="false">]</mo> </mrow> <msub> <mi>N</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>A</mi> </mrow> </msub> </mfrac> </mrow> <mo>=</mo> <mi>m</mi> <mo stretchy="false">[</mo> <mi>u</mi> <mo stretchy="false">]</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle {\frac {m[g/N_{p}e]}{N_{A}}}=m[u]}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/a8c9fb566ed47ffc1b9cc616dab7f11bcf42d8da" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.338ex; width:18.22ex; height:6.176ex;" alt="{\displaystyle {\frac {m[g/N_{p}e]}{N_{A}}}=m[u]}"></span></dd></dl> <p>dove: </p> <ul><li>m [g/N<sub>p</sub>e] è la massa molecolare espressa in grammi su numero di particelle elementari;</li> <li>m [u] è la massa molecolare espressa in unità di massa atomica;</li> <li>N<sub>A</sub> è la costante di Avogadro.</li></ul> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Calcolo">Calcolo</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Massa_molecolare&veaction=edit&section=1" title="Modifica la sezione Calcolo" class="mw-editsection-visualeditor"><span>modifica</span></a><span class="mw-editsection-divider"> | </span><a href="/w/index.php?title=Massa_molecolare&action=edit&section=1" title="Edit section's source code: Calcolo"><span>modifica wikitesto</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>La massa molecolare può essere calcolata come la <a href="/wiki/Addizione" title="Addizione">somma</a> delle <a href="/wiki/Massa_atomica" title="Massa atomica">masse atomiche</a> di tutti gli elementi costituenti la molecola. </p><p>Per esempio la massa molecolare dell'<a href="/wiki/Acqua" title="Acqua">acqua</a> (H<sub>2</sub>O) è la somma di due masse atomiche di <a href="/wiki/Idrogeno" title="Idrogeno">idrogeno</a> (1,00794 u) e una di <a href="/wiki/Ossigeno" title="Ossigeno">ossigeno</a> (15,9994 u): </p> <dl><dd><code>2 × 1,00794 u + 15,9994 u = 18,01528 u</code></dd></dl> <div class="mw-heading mw-heading2"><h2 id="Valori_tipici">Valori tipici</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Massa_molecolare&veaction=edit&section=2" title="Modifica la sezione Valori tipici" class="mw-editsection-visualeditor"><span>modifica</span></a><span class="mw-editsection-divider"> | </span><a href="/w/index.php?title=Massa_molecolare&action=edit&section=2" title="Edit section's source code: Valori tipici"><span>modifica wikitesto</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Le masse delle molecole ricadono in un intervallo di valori molto ampio: si va dalla più leggera H<sub>2</sub> (2,0158 g/mol) a centinaia di migliaia di u per le <a href="/wiki/Macromolecole" class="mw-redirect" title="Macromolecole">macromolecole</a>, quali per esempio i <a href="/wiki/Polimeri" class="mw-redirect" title="Polimeri">polimeri</a> sintetici o le <a href="/wiki/Proteina" class="mw-redirect" title="Proteina">proteine</a> e gli <a href="/wiki/Acidi_nucleici" title="Acidi nucleici">acidi nucleici</a>. </p><p>Per dare un'idea della massa di una molecola piccola, qual è per esempio quella dell'acqua, si tenga conto che 1 u = 1/N<sub>A</sub>=<span class="nowrap"><span data-sort-value="6973166054000000000♠"></span>1,66054<span style="margin-left:0.25em;margin-right:0.15em;">×</span>10<sup>−27</sup></span> <a href="/wiki/Chilogrammo" title="Chilogrammo">kg</a>, quindi in un grammo d'acqua ci sono circa N<sub>A</sub>/18,0=<span class="nowrap"><span data-sort-value="7022334000000000000♠"></span>3,34<span style="margin-left:0.25em;margin-right:0.15em;">×</span>10<sup>22</sup></span> <a href="/wiki/Molecola" title="Molecola">molecole</a>. </p> <div class="mw-heading mw-heading2"><h2 id="Peso_formula">Peso formula</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Massa_molecolare&veaction=edit&section=3" title="Modifica la sezione Peso formula" class="mw-editsection-visualeditor"><span>modifica</span></a><span class="mw-editsection-divider"> | </span><a href="/w/index.php?title=Massa_molecolare&action=edit&section=3" title="Edit section's source code: Peso formula"><span>modifica wikitesto</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Per i <a href="/wiki/Composto_chimico" title="Composto chimico">composti chimici</a> non molecolari e in particolare per i <a href="/wiki/Composti_ionici" class="mw-redirect" title="Composti ionici">composti ionici</a> e gli <a href="/wiki/Zwitterione" title="Zwitterione">zwitterioni</a>, non si può propriamente parlare di massa molecolare; si parla invece di <b>massa formula</b> riferendosi alla somma delle masse atomiche degli atomi che costituiscono la <a href="/wiki/Formula_minima" title="Formula minima">formula minima</a>. Per esempio la formula minima del <a href="/wiki/Solfato_di_sodio" title="Solfato di sodio">solfato di sodio</a> è Na<sub>2</sub>SO<sub>4</sub> quindi la sua massa formula è: </p> <dl><dd><code>2 × 22,98977 u + 32,06 + 4 × 15,9994 u = 142,04 u</code></dd></dl> <div class="mw-heading mw-heading2"><h2 id="Tipi_di_massa_molecolare">Tipi di massa molecolare</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Massa_molecolare&veaction=edit&section=4" title="Modifica la sezione Tipi di massa molecolare" class="mw-editsection-visualeditor"><span>modifica</span></a><span class="mw-editsection-divider"> | </span><a href="/w/index.php?title=Massa_molecolare&action=edit&section=4" title="Edit section's source code: Tipi di massa molecolare"><span>modifica wikitesto</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>A seconda dello scopo per il quale si calcolano o misurano masse molecolari, si possono ottenere diversi valori, in base a come si considerano gli <a href="/wiki/Isotopi" class="mw-redirect" title="Isotopi">isotopi</a>, atomi dello stesso elemento che hanno masse diverse. Tre modi differenti di calcolare masse molecolari sono: </p> <ul><li><a href="/wiki/Massa_nominale" title="Massa nominale">Massa nominale</a></li> <li><a href="/wiki/Massa_monoisotopica" title="Massa monoisotopica">Massa monoisotopica</a></li> <li><a href="/wiki/Massa_media" title="Massa media">Massa media</a></li></ul> <p>La massa calcolata è la <a href="/wiki/Massa_esatta" title="Massa esatta">massa esatta</a>, quella misurata (che sarà leggermente differente da quella calcolata) <a href="/wiki/Massa_accurata" title="Massa accurata">massa accurata</a>. </p> <div class="mw-heading mw-heading2"><h2 id="Miscele">Miscele</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Massa_molecolare&veaction=edit&section=5" title="Modifica la sezione Miscele" class="mw-editsection-visualeditor"><span>modifica</span></a><span class="mw-editsection-divider"> | </span><a href="/w/index.php?title=Massa_molecolare&action=edit&section=5" title="Edit section's source code: Miscele"><span>modifica wikitesto</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Una miscela è in genere costituita da molecole di masse differenti. Un esempio in tal senso sono le <a href="/wiki/Materie_plastiche" title="Materie plastiche">materie plastiche</a>, le quali sono costituite da diverse macromolecole con ciascuna la sua massa molecolare. In realtà anche ogni singolo <a href="/wiki/Elemento_chimico" title="Elemento chimico">elemento chimico</a> è una miscela di diversi <a href="/wiki/Isotopi" class="mw-redirect" title="Isotopi">isotopi</a>, ciascuno con la sua massa atomica. Esiste cioè una <a href="/wiki/Funzione_di_distribuzione" class="mw-redirect" title="Funzione di distribuzione">distribuzione</a> per la massa molecolare (o atomica). </p><p>In generale in <a href="/wiki/Statistica" title="Statistica">statistica</a> i parametri che caratterizzano una distribuzione ignota sono i suoi <a href="/wiki/Momento_(statistica)" class="mw-redirect" title="Momento (statistica)">momenti</a>, quindi in primo luogo la <a href="/wiki/Valore_atteso" title="Valore atteso">media</a>. Nel caso delle masse molecolari sono possibili diverse medie a seconda dei pesi statistici impiegati:<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> </p> <ul><li><b>(massa molecolare) media numerica, o <i>massa molare</i></b>: <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle m_{n}={\frac {\sum n_{i}m_{i}}{\sum n_{i}}}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msub> <mi>m</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>n</mi> </mrow> </msub> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mrow> <mo>∑</mo> <msub> <mi>n</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>i</mi> </mrow> </msub> <msub> <mi>m</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>i</mi> </mrow> </msub> </mrow> <mrow> <mo>∑</mo> <msub> <mi>n</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>i</mi> </mrow> </msub> </mrow> </mfrac> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle m_{n}={\frac {\sum n_{i}m_{i}}{\sum n_{i}}}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/861b0e781ce12c908114ccac92429f8649d76017" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.671ex; width:15.069ex; height:6.509ex;" alt="{\displaystyle m_{n}={\frac {\sum n_{i}m_{i}}{\sum n_{i}}}}"></span></li> <li><b>media ponderale</b>: <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle m_{w}={\frac {\sum w_{i}m_{i}}{\sum w_{i}}}={\frac {\sum n_{i}m_{i}^{2}}{\sum n_{i}m_{i}}}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msub> <mi>m</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>w</mi> </mrow> </msub> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mrow> <mo>∑</mo> <msub> <mi>w</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>i</mi> </mrow> </msub> <msub> <mi>m</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>i</mi> </mrow> </msub> </mrow> <mrow> <mo>∑</mo> <msub> <mi>w</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>i</mi> </mrow> </msub> </mrow> </mfrac> </mrow> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mrow> <mo>∑</mo> <msub> <mi>n</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>i</mi> </mrow> </msub> <msubsup> <mi>m</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>i</mi> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msubsup> </mrow> <mrow> <mo>∑</mo> <msub> <mi>n</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>i</mi> </mrow> </msub> <msub> <mi>m</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>i</mi> </mrow> </msub> </mrow> </mfrac> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle m_{w}={\frac {\sum w_{i}m_{i}}{\sum w_{i}}}={\frac {\sum n_{i}m_{i}^{2}}{\sum n_{i}m_{i}}}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/5bb40946af5ae59290d5982f3d05c789754c5628" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.671ex; width:27.593ex; height:6.676ex;" alt="{\displaystyle m_{w}={\frac {\sum w_{i}m_{i}}{\sum w_{i}}}={\frac {\sum n_{i}m_{i}^{2}}{\sum n_{i}m_{i}}}}"></span></li> <li><b>media zeta</b>: <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle m_{z}={\frac {\sum n_{i}m_{i}^{3}}{\sum n_{i}m_{i}^{2}}}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msub> <mi>m</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>z</mi> </mrow> </msub> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mrow> <mo>∑</mo> <msub> <mi>n</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>i</mi> </mrow> </msub> <msubsup> <mi>m</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>i</mi> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mn>3</mn> </mrow> </msubsup> </mrow> <mrow> <mo>∑</mo> <msub> <mi>n</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>i</mi> </mrow> </msub> <msubsup> <mi>m</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>i</mi> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msubsup> </mrow> </mfrac> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle m_{z}={\frac {\sum n_{i}m_{i}^{3}}{\sum n_{i}m_{i}^{2}}}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/e178c9b7567308e008f1eb83794e1169b5a85482" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -3.005ex; width:15.107ex; height:7.176ex;" alt="{\displaystyle m_{z}={\frac {\sum n_{i}m_{i}^{3}}{\sum n_{i}m_{i}^{2}}}}"></span></li> <li><b>media viscosimetrica</b>: <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle m_{v}=\left[{\frac {\sum n_{i}m_{i}^{(1+a)}}{\sum n_{i}m_{i}}}\right]^{\frac {1}{a}}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msub> <mi>m</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>v</mi> </mrow> </msub> <mo>=</mo> <msup> <mrow> <mo>[</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mrow> <mo>∑</mo> <msub> <mi>n</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>i</mi> </mrow> </msub> <msubsup> <mi>m</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>i</mi> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mo stretchy="false">(</mo> <mn>1</mn> <mo>+</mo> <mi>a</mi> <mo stretchy="false">)</mo> </mrow> </msubsup> </mrow> <mrow> <mo>∑</mo> <msub> <mi>n</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>i</mi> </mrow> </msub> <msub> <mi>m</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>i</mi> </mrow> </msub> </mrow> </mfrac> </mrow> <mo>]</mo> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>1</mn> <mi>a</mi> </mfrac> </mrow> </msup> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle m_{v}=\left[{\frac {\sum n_{i}m_{i}^{(1+a)}}{\sum n_{i}m_{i}}}\right]^{\frac {1}{a}}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/9e10718da1f26f7847a0b456d2ec3cb727dabc12" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -3.171ex; width:23.047ex; height:8.843ex;" alt="{\displaystyle m_{v}=\left[{\frac {\sum n_{i}m_{i}^{(1+a)}}{\sum n_{i}m_{i}}}\right]^{\frac {1}{a}}}"></span></li></ul> <p>dove: </p> <ul><li><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle m_{i}\!\ }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msub> <mi>m</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>i</mi> </mrow> </msub> <mspace width="negativethinmathspace" /> <mtext> </mtext> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle m_{i}\!\ }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/584db91020856f5b2f1165a01cb288541e6d5e56" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:3.034ex; height:2.009ex;" alt="{\displaystyle m_{i}\!\ }"></span> è la massa molecolare dell'i-esima molecola;</li> <li><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle n_{i}\!\ }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msub> <mi>n</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>i</mi> </mrow> </msub> <mspace width="negativethinmathspace" /> <mtext> </mtext> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle n_{i}\!\ }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/14eb81c6ebad361dba7f97bf4f077a6fd1447663" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:2.388ex; height:2.009ex;" alt="{\displaystyle n_{i}\!\ }"></span> è la <a href="/wiki/Quantit%C3%A0_di_sostanza" title="Quantità di sostanza">quantità di molecole</a> aventi massa molecolare pari a <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle m_{i}\!\ }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msub> <mi>m</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>i</mi> </mrow> </msub> <mspace width="negativethinmathspace" /> <mtext> </mtext> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle m_{i}\!\ }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/584db91020856f5b2f1165a01cb288541e6d5e56" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:3.034ex; height:2.009ex;" alt="{\displaystyle m_{i}\!\ }"></span>;</li> <li><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle w_{i}\!\ }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msub> <mi>w</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>i</mi> </mrow> </msub> <mspace width="negativethinmathspace" /> <mtext> </mtext> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle w_{i}\!\ }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/56332a95a1dcb00bd7757ac6080e7cdfdf5ebdb4" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:2.657ex; height:2.009ex;" alt="{\displaystyle w_{i}\!\ }"></span> è la frazione ponderale delle molecole con massa molecolare pari a <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle m_{i}\!\ }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msub> <mi>m</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>i</mi> </mrow> </msub> <mspace width="negativethinmathspace" /> <mtext> </mtext> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle m_{i}\!\ }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/584db91020856f5b2f1165a01cb288541e6d5e56" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:3.034ex; height:2.009ex;" alt="{\displaystyle m_{i}\!\ }"></span>;</li> <li><i>a</i> è l'esponente dell'<a href="/wiki/Equazione_di_Mark-Houwink" title="Equazione di Mark-Houwink">equazione di Mark-Houwink</a>.</li></ul> <p>Il rapporto tra la massa molecolare media ponderale e quella media numerica è detto "<a href="/wiki/Indice_di_polidispersione" title="Indice di polidispersione">indice di polidispersione</a>" ed è una misura della <a href="/wiki/Indice_di_dispersione" title="Indice di dispersione">dispersione</a> delle masse molecolari. </p><p>Massa molecolare (o atomica) media numerica e massa molare sono in effetti la stessa <a href="/wiki/Grandezza_fisica" title="Grandezza fisica">grandezza fisica</a> (rapporto <a href="/wiki/Massa_(fisica)" title="Massa (fisica)">massa</a>/<a href="/wiki/Quantit%C3%A0_di_sostanza" title="Quantità di sostanza">quantità di sostanza</a> di una sostanza), hanno solo diverse <a href="/wiki/Unit%C3%A0_di_misura" title="Unità di misura">unità di misura</a>. Nella massa molecolare l'unità di quantità di sostanza è una molecola (cioè è adimensionale), mentre nella massa molare si riferisce a una mole. </p><p>Per esempio l'idrogeno, che ha massa atomica media di 1,00794 g/mol, ovvero di 1,00794/(6.022x 10^23) g = 1.6737 x 10^-24 g. Non esiste però un atomo di idrogeno che abbia questa massa, ma un atomo di idrogeno in una miscela di idrogeno naturale può avere solo due valori di massa monoisotopica: circa 1 g/mol (nel 99,985% dei casi, ed è di <a href="/wiki/Prozio_(chimica)" title="Prozio (chimica)">prozio</a>), e circa 2 g/mol (solo nello 0,015% dei casi, ed è di <a href="/wiki/Deuterio" title="Deuterio">deuterio</a>). Siccome la molecola di idrogeno è H<sub>2</sub>, la sua massa molecolare media è il doppio della massa atomica media dell'idrogeno. Ma di nuovo non c'è neanche una molecola in un gas di idrogeno che abbia quella massa: l'idrogeno naturale è costituito solo da molecole prozio-prozio da circa 2 g/mol, prozio-deuterio da circa 3 g/mol e deuterio-deuterio da circa 4 g/mol. In altri termini bisogna distinguere i concetti di <a href="/wiki/Media_(statistica)" title="Media (statistica)">media</a> e <a href="/wiki/Mediana_(statistica)" title="Mediana (statistica)">mediana</a>: la <a href="/wiki/Frequenza_statistica" class="mw-redirect" title="Frequenza statistica">frequenza statistica</a> di queste masse medie in una miscela è generalmente zero perché le masse atomiche hanno valori discreti (sono quantizzate). </p><p>La massa molare di un polimero aumenta all'aumentare del tempo durante il quale è svolta la <a href="/wiki/Reazione_chimica" title="Reazione chimica">reazione chimica</a> di <a href="/wiki/Polimerizzazione" title="Polimerizzazione">polimerizzazione</a> (che consiste appunto nell'allungamento delle catene polimeriche), mentre l'indice di polidispersione dipende anzitutto dal <a href="/wiki/Meccanismo_di_reazione" title="Meccanismo di reazione">meccanismo di reazione</a>: nel caso di <a href="/wiki/Polimerizzazione_a_catena" title="Polimerizzazione a catena">polimerizzazione a catena</a> (che in genere è <a href="/w/index.php?title=Attivazione_termica&action=edit&redlink=1" class="new" title="Attivazione termica (la pagina non esiste)">attivata termicamente</a>) si ha un indice di polidispersione più elevato, mentre nel caso di <a href="/wiki/Polimerizzazione_a_stadi" title="Polimerizzazione a stadi">polimerizzazione a stadi</a> (che in genere è <a href="/wiki/Energia_di_attivazione" title="Energia di attivazione">attivata</a> attraverso l'impiego di <a href="/wiki/Catalizzatori" class="mw-redirect" title="Catalizzatori">catalizzatori</a>) si ha un indice di polidispersione più basso. </p> <div class="mw-heading mw-heading2"><h2 id="Massa_molecolare_e_relatività_speciale"><span id="Massa_molecolare_e_relativit.C3.A0_speciale"></span>Massa molecolare e relatività speciale</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Massa_molecolare&veaction=edit&section=6" title="Modifica la sezione Massa molecolare e relatività speciale" class="mw-editsection-visualeditor"><span>modifica</span></a><span class="mw-editsection-divider"> | </span><a href="/w/index.php?title=Massa_molecolare&action=edit&section=6" title="Edit section's source code: Massa molecolare e relatività speciale"><span>modifica wikitesto</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>A voler esser rigorosi, la massa molecolare non è esattamente uguale alla somma delle masse atomiche degli atomi presenti nella molecola. L'applicazione della <a href="/wiki/Teoria_della_relativit%C3%A0" title="Teoria della relatività">teoria della relatività</a> porterebbe a una piccola correzione pari a <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle -\Delta E/c^{2}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mo>−</mo> <mi mathvariant="normal">Δ</mi> <mi>E</mi> <mrow class="MJX-TeXAtom-ORD"> <mo>/</mo> </mrow> <msup> <mi>c</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle -\Delta E/c^{2}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/3d83efe529f2059ef3f5d1c3ca4d879e197846bc" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:8.743ex; height:3.176ex;" alt="{\displaystyle -\Delta E/c^{2}}"></span>, dove Δ E è l'<a href="/wiki/Energia" title="Energia">energia</a> di legame della molecola e <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle c}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>c</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle c}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/86a67b81c2de995bd608d5b2df50cd8cd7d92455" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.007ex; height:1.676ex;" alt="{\displaystyle c}"></span> è la <a href="/wiki/Velocit%C3%A0_della_luce" title="Velocità della luce">velocità della luce</a>. Tuttavia tale correzione è di entità trascurabile. Per esempio, l'energia di legame di una singola molecola d'acqua è circa <span class="nowrap"><span data-sort-value="6982153900000000000♠"></span>1,539<span style="margin-left:0.25em;margin-right:0.15em;">×</span>10<sup>−18</sup></span> <a href="/wiki/Joule" title="Joule">J</a>, quindi la correzione sarebbe dell'ordine di 10<sup>−5</sup> <i>u</i>, cioè pari ad appena 0.6 ppm. </p> <div class="mw-heading mw-heading2"><h2 id="Note">Note</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Massa_molecolare&veaction=edit&section=7" title="Modifica la sezione Note" class="mw-editsection-visualeditor"><span>modifica</span></a><span class="mw-editsection-divider"> | </span><a href="/w/index.php?title=Massa_molecolare&action=edit&section=7" title="Edit section's source code: Note"><span>modifica wikitesto</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-references-wrap"><ol class="references"> <li id="cite_note-1"><a href="#cite_ref-1"><b>^</b></a> <span class="reference-text">R.J. Young and P.A. Lovell, Introduction to Polymers, 1991.</span> </li> </ol></div> <div class="mw-heading mw-heading2"><h2 id="Voci_correlate">Voci correlate</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Massa_molecolare&veaction=edit&section=8" title="Modifica la sezione Voci correlate" class="mw-editsection-visualeditor"><span>modifica</span></a><span class="mw-editsection-divider"> | </span><a href="/w/index.php?title=Massa_molecolare&action=edit&section=8" title="Edit section's source code: Voci correlate"><span>modifica wikitesto</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/Densit%C3%A0" title="Densità">Densità</a></li> <li><a href="/wiki/Massa_molare" title="Massa molare">Massa molare</a></li> <li><a href="/wiki/Molecola" title="Molecola">Molecola</a></li> <li><a href="/wiki/Peso_atomico" class="mw-redirect" title="Peso atomico">Peso atomico</a></li> <li><a href="/wiki/Quantit%C3%A0_di_sostanza" title="Quantità di sostanza">Quantità di sostanza</a></li> <li><a href="/wiki/Unit%C3%A0_di_massa_atomica" title="Unità di massa atomica">Unità di massa atomica</a></li> <li><a href="/wiki/Volume_molare" title="Volume molare">Volume molare</a></li></ul> <div class="mw-heading mw-heading2"><h2 id="Collegamenti_esterni">Collegamenti esterni</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Massa_molecolare&veaction=edit&section=9" title="Modifica la sezione Collegamenti esterni" class="mw-editsection-visualeditor"><span>modifica</span></a><span class="mw-editsection-divider"> | </span><a href="/w/index.php?title=Massa_molecolare&action=edit&section=9" title="Edit section's source code: Collegamenti esterni"><span>modifica wikitesto</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li class="mw-empty-elt"></li> <li><cite id="CITEREFBritannica.com" class="citation web" style="font-style:normal">(<span style="font-weight:bolder; font-size:80%"><abbr title="inglese">EN</abbr></span>) <a rel="nofollow" class="external text" href="https://www.britannica.com/science/molecular-weight"><span style="font-style:italic;">molecular weight</span></a>, su <span style="font-style:italic;"><a href="/wiki/Enciclopedia_Britannica" title="Enciclopedia Britannica">Enciclopedia Britannica</a></span>, Encyclopædia Britannica, Inc.</cite> <span class="mw-valign-text-top noprint" typeof="mw:File/Frameless"><a href="https://www.wikidata.org/wiki/Q182854#P1417" title="Modifica su Wikidata"><img alt="Modifica su Wikidata" src="//upload.wikimedia.org/wikipedia/commons/thumb/7/73/Blue_pencil.svg/10px-Blue_pencil.svg.png" decoding="async" width="10" height="10" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/7/73/Blue_pencil.svg/15px-Blue_pencil.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/7/73/Blue_pencil.svg/20px-Blue_pencil.svg.png 2x" data-file-width="600" data-file-height="600" /></a></span></li> <li><cite class="citation web" style="font-style:normal"> <a rel="nofollow" class="external text" href="http://www.itchiavari.org/chimica/lab/mmgas.html"><span style="font-style:italic;">Determinazione della massa molecolare di un gas in base alla velocità di diffusione</span></a> <style data-mw-deduplicate="TemplateStyles:r140554517">.mw-parser-output .chiarimento{background:#ffeaea;color:#444444}.mw-parser-output .chiarimento-apice{color:#EE0700}@media screen{html.skin-theme-clientpref-night .mw-parser-output .chiarimento{background:rgba(179,36,36,0.21);color:inherit}html.skin-theme-clientpref-night .mw-parser-output .chiarimento-apice{color:#b32424}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .chiarimento{background:rgba(179,36,36,0.21);color:inherit}html.skin-theme-clientpref-os .mw-parser-output .chiarimento-apice{color:#b32424}}</style><span class="chiarimento" title="A volte può capitare che un link presente su Wikipedia non sia più raggiungibile. Se possibile ritrova il link e inserisci il collegamento corretto, comunque non rimuovere il collegamento e inserisci il template {{Collegamento interrotto}}"></span><sup class="noprint chiarimento-apice" title="A volte può capitare che un link presente su Wikipedia non sia più raggiungibile. Se possibile ritrova il link e inserisci il collegamento corretto, comunque non rimuovere il collegamento e inserisci il template {{Collegamento interrotto}}">[<i><a href="/wiki/Aiuto:Collegamenti_interrotti" title="Aiuto:Collegamenti interrotti">collegamento interrotto</a></i>]</sup>, su <span style="font-style:italic;">itchiavari.org</span>.</cite></li></ul> <style data-mw-deduplicate="TemplateStyles:r140554510">.mw-parser-output .CdA{border:1px solid #aaa;width:100%;margin:auto;font-size:90%;padding:2px}.mw-parser-output .CdA th{background-color:#f2f2f2;font-weight:bold;width:20%}@media screen{html.skin-theme-clientpref-night .mw-parser-output .CdA{border-color:#54595D}html.skin-theme-clientpref-night .mw-parser-output .CdA th{background-color:#202122}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .CdA{border-color:#54595D}html.skin-theme-clientpref-os .mw-parser-output .CdA th{background-color:#202122}}</style><table class="CdA"><tbody><tr><th><a href="/wiki/Aiuto:Controllo_di_autorit%C3%A0" title="Aiuto:Controllo di autorità">Controllo di autorità</a></th><td><a href="/wiki/Nuovo_soggettario" title="Nuovo soggettario">Thesaurus BNCF</a> <span class="uid"><a rel="nofollow" class="external text" href="https://thes.bncf.firenze.sbn.it/termine.php?id=38178">38178</a></span><span style="font-weight:bold;"> ·</span> <a href="/wiki/Library_of_Congress_Control_Number" title="Library of Congress Control Number">LCCN</a> <span class="uid">(<span style="font-weight:bolder; font-size:80%"><abbr title="inglese">EN</abbr></span>) <a rel="nofollow" class="external text" href="http://id.loc.gov/authorities/subjects/sh85086596">sh85086596</a></span><span style="font-weight:bold;"> ·</span> <a href="/wiki/Gemeinsame_Normdatei" title="Gemeinsame Normdatei">GND</a> <span class="uid">(<span style="font-weight:bolder; font-size:80%"><abbr title="tedesco">DE</abbr></span>) <a rel="nofollow" class="external text" href="https://d-nb.info/gnd/4170374-1">4170374-1</a></span><span style="font-weight:bold;"> ·</span> <a href="/wiki/Biblioteca_nazionale_di_Francia" title="Biblioteca nazionale di Francia">BNF</a> <span class="uid">(<span style="font-weight:bolder; font-size:80%"><abbr title="francese">FR</abbr></span>) <a rel="nofollow" class="external text" href="https://catalogue.bnf.fr/ark:/12148/cb119788818">cb119788818</a> <a rel="nofollow" class="external text" href="https://data.bnf.fr/ark:/12148/cb119788818">(data)</a></span><span style="font-weight:bold;"> ·</span> <a href="/wiki/Biblioteca_nazionale_di_Israele" title="Biblioteca nazionale di Israele">J9U</a> <span class="uid">(<span style="font-weight:bolder; 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