{"id":5754,"date":"2026-10-14T23:10:00","date_gmt":"2026-10-14T20:10:00","guid":{"rendered":"https:\/\/wpcalc.com\/fr\/chimie\/loi-de-gay-lussac\/"},"modified":"2026-10-14T23:10:00","modified_gmt":"2026-10-14T20:10:00","slug":"loi-de-gay-lussac","status":"publish","type":"post","link":"https:\/\/wpcalc.com\/fr\/chimie\/loi-de-gay-lussac\/","title":{"rendered":"Calculateur de la loi de Gay-Lussac"},"content":{"rendered":"<section class=\"not-prose calculator-box\" aria-labelledby=\"calculator-title\"><div class=\"flex items-baseline sm:items-center justify-between gap-2 sm:gap-3\"><div class=\"flex flex-col sm:flex-row sm:items-center gap-2\"><span class=\"icon icon-calculator text-primary-700! text-base! dark:text-primary-300!\" aria-hidden=\"true\"><\/span><h2 id=\"calculator-title\" class=\"text-lg font-display font-bold\">Calculer la pression ou la temp\u00e9rature \u00e0 volume constant<\/h2><\/div><div class=\"calcdash-favorite group\">\n  <button type=\"button\" class=\"favorite\" id=\"favorite\" data-favorite-id=\"5754\" data-favorite-title=\"Loi de Gay-Lussac\" data-favorite-url=\"https:\/\/wpcalc.com\/fr\/chimie\/loi-de-gay-lussac\/\" data-favorite-excerpt=\"Calculez comment la pression d&#039;un gaz varie avec la temp\u00e9rature dans un contenant herm\u00e9tique et rigide gr\u00e2ce \u00e0 la loi de Gay-Lussac. Saisissez la pression et la temp\u00e9rature initiales, ainsi qu&#039;une valeur finale, pour trouver l&#039;autre.\" aria-label=\"Ajouter aux favoris\" data-favorite-icon=\"icon icon-wind-2\">\n    <span class=\"icon icon-shape-star-empty\" aria-hidden=\"true\"><\/span>\n  <\/button>\n  <div class=\"calcdash-favorite__tip\" aria-hidden=\"true\">\n   <span class=\"favorite-tooltip\" id=\"favorite-tooltip\"><\/span>\n  <\/div>\n  <span class=\"sr-only\" role=\"status\" id=\"favorite-status\"><\/span>\n<\/div><\/div><form action=\"https:\/\/wpcalc.com\/fr\/chimie\/loi-de-gay-lussac\/\" method=\"POST\" class=\"calculator\" id=\"calculator-5754\" data-post=\"5754\"><fieldset class=\"fieldset-input is-1\"><legend class=\"sr-only\">Champs de saisie<\/legend><div class=\"is-single field\" id=\"input-1\"><span class=\"font-semibold\">\u00c9tat initial<\/span><\/div><div class=\"field has-term\" id=\"input-2\"><label for=\"field-2\">Pression initiale (P\u2081)<\/label><div class=\"term\">P\u2081<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><div class=\"field-group\"><input type=\"number\" name=\"pression_initiale_p\" id=\"field-2\" aria-describedby=\"calc-info-2\" step=\"any\" value=\"2\"\/><div class=\"grid grid-cols-1\"><select id=\"field-3\" name=\"unit\" aria-label=\"Unit\u00e9\"><option value=\"atm\" selected>atm<\/option><option value=\"kPa\">kPa<\/option><option value=\"mmHg\">mmHg<\/option><option value=\"bar\">bar<\/option><option value=\"psi\">psi<\/option><\/select><svg class=\"pointer-events-none col-start-1 row-start-1 mr-2 size-5 self-center justify-self-end text-gray-500 sm:size-4\" viewBox=\"0 0 16 16\" fill=\"currentColor\" aria-hidden=\"true\" data-slot=\"icon\">\n              <path fill-rule=\"evenodd\" d=\"M4.22 6.22a.75.75 0 0 1 1.06 0L8 8.94l2.72-2.72a.75.75 0 1 1 1.06 1.06l-3.25 3.25a.75.75 0 0 1-1.06 0L4.22 7.28a.75.75 0 0 1 0-1.06Z\" clip-rule=\"evenodd\" \/>\n            <\/svg><\/div><\/div><small id=\"calc-info-2\">Pression du gaz au d\u00e9part.<\/small><\/div><div class=\"field has-term\" id=\"input-3\"><label for=\"field-4\">Temp\u00e9rature initiale (T\u2081)<\/label><div class=\"term\">T\u2081<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><div class=\"field-group\"><input type=\"number\" name=\"temprature_initiale_t\" id=\"field-4\" aria-describedby=\"calc-info-4\" step=\"any\" value=\"300\"\/><div class=\"grid grid-cols-1\"><select id=\"field-5\" name=\"unit\" aria-label=\"Unit\u00e9\"><option value=\"K\" selected>K<\/option><option value=\"C\">\u00b0C<\/option><option value=\"F\">\u00b0F<\/option><\/select><svg class=\"pointer-events-none col-start-1 row-start-1 mr-2 size-5 self-center justify-self-end text-gray-500 sm:size-4\" viewBox=\"0 0 16 16\" fill=\"currentColor\" aria-hidden=\"true\" data-slot=\"icon\">\n              <path fill-rule=\"evenodd\" d=\"M4.22 6.22a.75.75 0 0 1 1.06 0L8 8.94l2.72-2.72a.75.75 0 1 1 1.06 1.06l-3.25 3.25a.75.75 0 0 1-1.06 0L4.22 7.28a.75.75 0 0 1 0-1.06Z\" clip-rule=\"evenodd\" \/>\n            <\/svg><\/div><\/div><small id=\"calc-info-4\">Temp\u00e9rature absolue\u00a0; les valeurs en \u00b0C et \u00b0F sont automatiquement converties en kelvins.<\/small><\/div><div class=\"is-single field\" id=\"input-4\"><span class=\"font-semibold\">\u00c9tat final<\/span><\/div><div class=\"field is-single\" id=\"input-5\"><label for=\"field-7\">Calculer<\/label><div class=\"grid grid-cols-1\"><select id=\"field-7\" name=\"calculer\"><option value=\"p\" selected>Pression finale (P\u2082)<\/option><option value=\"t\">Temp\u00e9rature finale (T\u2082)<\/option><\/select><svg class=\"pointer-events-none col-start-1 row-start-1 mr-2 size-5 self-center justify-self-end text-gray-500 sm:size-4\" viewBox=\"0 0 16 16\" fill=\"currentColor\" aria-hidden=\"true\" data-slot=\"icon\">\n              <path fill-rule=\"evenodd\" d=\"M4.22 6.22a.75.75 0 0 1 1.06 0L8 8.94l2.72-2.72a.75.75 0 1 1 1.06 1.06l-3.25 3.25a.75.75 0 0 1-1.06 0L4.22 7.28a.75.75 0 0 1 0-1.06Z\" clip-rule=\"evenodd\" \/>\n            <\/svg><\/div><\/div><div class=\"field has-term\" id=\"input-6\" hidden><label for=\"field-8\">Pression finale (P\u2082)<\/label><div class=\"term\">P\u2082<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><div class=\"field-group\"><input type=\"number\" name=\"pression_finale_p\" id=\"field-8\" aria-describedby=\"calc-info-8\" step=\"any\" value=\"3\"\/><div class=\"grid grid-cols-1\"><select id=\"field-9\" name=\"unit\" aria-label=\"Unit\u00e9\"><option value=\"atm\" selected>atm<\/option><option value=\"kPa\">kPa<\/option><option value=\"mmHg\">mmHg<\/option><option value=\"bar\">bar<\/option><option value=\"psi\">psi<\/option><\/select><svg class=\"pointer-events-none col-start-1 row-start-1 mr-2 size-5 self-center justify-self-end text-gray-500 sm:size-4\" viewBox=\"0 0 16 16\" fill=\"currentColor\" aria-hidden=\"true\" data-slot=\"icon\">\n              <path fill-rule=\"evenodd\" d=\"M4.22 6.22a.75.75 0 0 1 1.06 0L8 8.94l2.72-2.72a.75.75 0 1 1 1.06 1.06l-3.25 3.25a.75.75 0 0 1-1.06 0L4.22 7.28a.75.75 0 0 1 0-1.06Z\" clip-rule=\"evenodd\" \/>\n            <\/svg><\/div><\/div><small id=\"calc-info-8\">Saisissez la pression finale connue lorsque vous calculez la temp\u00e9rature. Le r\u00e9sultat est exprim\u00e9 dans l\u2019unit\u00e9 choisie ici.<\/small><\/div><div class=\"field has-term\" id=\"input-7\"><label for=\"field-10\">Temp\u00e9rature finale (T\u2082)<\/label><div class=\"term\">T\u2082<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><div class=\"field-group\"><input type=\"number\" name=\"temprature_finale_t\" id=\"field-10\" aria-describedby=\"calc-info-10\" step=\"any\" value=\"450\"\/><div class=\"grid grid-cols-1\"><select id=\"field-11\" name=\"unit\" aria-label=\"Unit\u00e9\"><option value=\"K\" selected>K<\/option><option value=\"C\">\u00b0C<\/option><option value=\"F\">\u00b0F<\/option><\/select><svg class=\"pointer-events-none col-start-1 row-start-1 mr-2 size-5 self-center justify-self-end text-gray-500 sm:size-4\" viewBox=\"0 0 16 16\" fill=\"currentColor\" aria-hidden=\"true\" data-slot=\"icon\">\n              <path fill-rule=\"evenodd\" d=\"M4.22 6.22a.75.75 0 0 1 1.06 0L8 8.94l2.72-2.72a.75.75 0 1 1 1.06 1.06l-3.25 3.25a.75.75 0 0 1-1.06 0L4.22 7.28a.75.75 0 0 1 0-1.06Z\" clip-rule=\"evenodd\" \/>\n            <\/svg><\/div><\/div><small id=\"calc-info-10\">Saisissez la temp\u00e9rature finale connue lorsque vous calculez la pression. Les valeurs en \u00b0C et \u00b0F sont automatiquement converties en kelvins.<\/small><\/div><\/fieldset><div class=\"buttons\"><button type=\"submit\" data-text=\"Recalculer\" id=\"calculate-button\" data-post=\"5754\">Calculer<\/button><button type=\"reset\">R\u00e9initialiser<\/button><\/div><div class=\"field is-checkbox hidden!\" id=\"field-auto-calc\"><input type=\"checkbox\" id=\"auto-calc\"><label for=\"auto-calc\">Calculer automatiquement<\/label><small>Si activ\u00e9, le r\u00e9sultat se met \u00e0 jour automatiquement d\u00e8s que vous modifiez une valeur.<\/small><\/div><div class=\"fieldset-result is-hidden\" aria-labelledby=\"result-title\" aria-live=\"polite\" role=\"region\"> <h3 class=\"result-title bg-gradient-to-r from-primary-50 to-gray-50 dark:from-primary-900 dark:to-gray-800\" id=\"result-title\"><span class=\"icon icon-s-pulse\" aria-hidden=\"true\"><\/span> R\u00e9sultat \u00e0 volume constant<\/h3><div class=\"result-box\"><div class=\"field-result\" id=\"output-1\"><span class=\"field-title\"><span>Pression finale (P\u2082)<\/span><span class=\"result-term\">P\u2082<\/span><\/span><span class=\"field-value\" id=\"result-1\"><\/span><button type=\"button\" class=\"copy-result\" data-tooltip=\"Copier le r\u00e9sultat\" aria-label=\"Copier le r\u00e9sultat\"><span class=\"copy-icon icon icon-document-copy\" aria-hidden=\"true\"><\/span><\/button><\/div><div class=\"field-result\" id=\"output-2\"><span class=\"field-title\"><span>Temp\u00e9rature finale (T\u2082)<\/span><span class=\"result-term\">T\u2082<\/span><\/span><span class=\"field-value\" id=\"result-2\"><\/span><button type=\"button\" class=\"copy-result\" data-tooltip=\"Copier le r\u00e9sultat\" aria-label=\"Copier le r\u00e9sultat\"><span class=\"copy-icon icon icon-document-copy\" aria-hidden=\"true\"><\/span><\/button><\/div><div class=\"field-result\" id=\"output-3\"><span class=\"field-title\"><span>Rapport P\/T (constant)<\/span><span class=\"result-term\">P\/T<\/span><\/span><span class=\"field-value\" id=\"result-3\"><\/span><button type=\"button\" class=\"copy-result\" data-tooltip=\"Copier le r\u00e9sultat\" aria-label=\"Copier le r\u00e9sultat\"><span class=\"copy-icon icon icon-document-copy\" aria-hidden=\"true\"><\/span><\/button><\/div><div class=\"field-result is-column\" id=\"output-4\"><span class=\"field-title\"><span>D\u00e9tails du calcul<\/span><\/span><span class=\"field-value\" id=\"result-4\"><\/span><button type=\"button\" class=\"copy-result\" data-tooltip=\"Copier le r\u00e9sultat\" aria-label=\"Copier le r\u00e9sultat\"><span class=\"copy-icon icon icon-document-copy\" aria-hidden=\"true\"><\/span><\/button><\/div><div class=\"field-result is-column\" id=\"output-5\"><span class=\"field-title\"><span>Formule et hypoth\u00e8ses<\/span><\/span><span class=\"field-value\" id=\"result-5\"><\/span><button type=\"button\" class=\"copy-result\" data-tooltip=\"Copier le r\u00e9sultat\" aria-label=\"Copier le r\u00e9sultat\"><span class=\"copy-icon icon icon-document-copy\" aria-hidden=\"true\"><\/span><\/button><\/div><\/div><div class=\"result-actions\"><button type=\"button\" class=\"copy-link\"><svg viewBox=\"0 0 20 20\" fill=\"currentColor\" aria-hidden=\"true\"><path d=\"M12.232 4.232a2.5 2.5 0 0 1 3.536 3.536l-1.225 1.224a.75.75 0 0 0 1.061 1.06l1.224-1.224a4 4 0 0 0-5.656-5.656l-3 3a4 4 0 0 0 .225 5.865.75.75 0 0 0 .977-1.138 2.5 2.5 0 0 1-.142-3.667l3-3Z\"\/><path d=\"M11.603 7.963a.75.75 0 0 0-.977 1.138 2.5 2.5 0 0 1 .142 3.667l-3 3a2.5 2.5 0 0 1-3.536-3.536l1.225-1.224a.75.75 0 0 0-1.061-1.06l-1.224 1.224a4 4 0 1 0 5.656 5.656l3-3a4 4 0 0 0-.225-5.865Z\"\/><\/svg><span class=\"copy-link__text\">Copier le lien vers ce calcul<\/span><\/button><span class=\"sr-only\" role=\"status\" id=\"copy-link-status\"><\/span><\/div><\/div><a href=\"#respond\" class=\"hidden transition-opacity duration-300 opacity-0 w-50 text-sm justify-center items-center gap-2 px-4 py-2 rounded bg-gray-200 text-gray-700 hover:bg-gray-300\" id=\"leave-comment\"><span class=\"icon icon-comments\" aria-hidden=\"true\"><\/span>Laisser un commentaire<\/a><\/form><\/section><section id=\"calc-reactions\" class=\"not-prose hidden my-12 bg-gradient-to-r from-primary-50 to-gray-50 border border-indigo-100 rounded-xl px-6 py-4 shadow-sm\" data-post=\"5754\" aria-live=\"polite\" aria-labelledby=\"calc-reactions-title\"><p id=\"calc-reactions-title\" class=\"text-sm text-gray-500 text-center mb-2\">Que pensez-vous de ce r\u00e9sultat\u00a0?<\/p><div role=\"group\" aria-labelledby=\"calc-reactions-title\" class=\"grid grid-cols-3 sm:flex sm:flex-row sm:justify-around gap-4 sm:items-center sm:flex-wrap\"><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"like\"><span class=\"reaction-count\" data-reaction-count=\"like\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\ud83d\ude00 <\/span><span class=\"reaction-description font-medium\">J\u2019aime <\/span><\/button><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"helpful\"><span class=\"reaction-count\" data-reaction-count=\"helpful\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\ud83d\udca1 <\/span><span class=\"reaction-description font-medium\">Utile <\/span><\/button><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"confused\"><span class=\"reaction-count\" data-reaction-count=\"confused\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\ud83d\ude15 <\/span><span class=\"reaction-description font-medium\">Confus <\/span><\/button><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"disappointed\"><span class=\"reaction-count\" data-reaction-count=\"disappointed\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\ud83d\ude1e <\/span><span class=\"reaction-description font-medium\">D\u00e9\u00e7u <\/span><\/button><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"inaccurate\"><span class=\"reaction-count\" data-reaction-count=\"inaccurate\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\u274c <\/span><span class=\"reaction-description font-medium\">Inexact <\/span><\/button><\/div><div id=\"reaction-message\" class=\"hidden mt-8 rounded-md border border-primary-100 bg-white\/50 backdrop-blur-sm px-4 py-2 text-sm text-center shadow-sm\"><\/div><\/section><div class=\"calcdash-ad not-prose calcdash-ad--calc_result calcdash-ad--in-article\"><ins class=\"adsbygoogle\" style=\"display:block\" data-ad-client=\"ca-pub-1721569815777345\" data-ad-slot=\"6317458308\" data-ad-layout=\"in-article\" data-ad-format=\"fluid\"><\/ins><script>(adsbygoogle = window.adsbygoogle || []).push({});<\/script><\/div>\n<style id=\"wpcoderpro-inline-1\">.formula-box {\r\n\tborder-bottom: none !important;\r\n}<\/style><section class=\"formula-box\" aria-labelledby=\"formula-title\">\r\n\t<div id=\"formula-title\" class=\"not-prose font-display mb-4\"><span class=\"icon icon-formula\" aria-hidden=\"true\"><\/span><h2>Formule de la loi de Gay-Lussac<\/h2><\/div>\r\n\t<figure class=\"not-prose formula\">\r\n\t\t<figcaption class=\"formula-title\">Formule<\/figcaption>\r\n\t\t<div class=\"text-base text-gray-800\" id=\"formula\">\n\\[ \\frac{P_1}{T_1} = \\frac{P_2}{T_2} \\quad \\Longrightarrow \\quad P_2 = P_1 \\cdot \\frac{T_2}{T_1}, \\quad T_2 = T_1 \\cdot \\frac{P_2}{P_1} \\]\n<\/div>\r\n\t<\/figure>\r\n\t<\/p>\n<p><strong>O\u00f9\\u00A0:<\/strong><\/p>\n<ul>\n<li>\\(P_1\\) \u2014 pression initiale du gaz<\/li>\n<li>\\(T_1\\) \u2014 temp\u00e9rature absolue initiale (en kelvins)<\/li>\n<li>\\(P_2\\) \u2014 pression finale du gaz<\/li>\n<li>\\(T_2\\) \u2014 temp\u00e9rature absolue finale (en kelvins)<\/li>\n<\/ul>\n<p>La formule exprime qu'\u00e0 volume constant, la pression d'une quantit\u00e9 fixe de gaz est directement proportionnelle \u00e0 sa temp\u00e9rature absolue\\u00A0: le rapport \\(P\/T\\) reste identique avant et apr\u00e8s toute transformation.<\/p>\n<p>\r\n<\/section>\n<style id=\"wpcoderpro-inline-2\">.calculation-box {\r\n\tborder-bottom: none !important;\r\n}<\/style><section id=\"calculation\" class=\"calculation-box\" aria-labelledby=\"calculation-title\">\r\n\t<div id=\"calculation-title\" class=\"not-prose font-display\"><span class=\"icon icon-unordered-list\" aria-hidden=\"true\"><\/span><h2>Loi de Gay-Lussac \u2013 Exemple de calcul<\/h2><\/div>\r\n\r\n<\/p>\n<p><strong>Exemple\\u00A0:<\/strong> une bonbonne en acier rigide contient un gaz \u00e0 2 atm et 300 K. On la chauffe jusqu'\u00e0 ce que le gaz atteigne 450 K. Quelle est la pression finale\\u00A0?<\/p>\n<p>\\[ P_2 = P_1 \\cdot \\frac{T_2}{T_1} = 2\\ \\text{atm} \\times \\frac{450\\ \\text{K}}{300\\ \\text{K}} = 3\\ \\text{atm} \\]<\/p>\n<p><strong>R\u00e9sultat\\u00A0:<\/strong> la pression finale est de 3 atm. La v\u00e9rification donne \\(P_1\/T_1 = 0.006667\\) atm\/K et \\(P_2\/T_2 = 0.006667\\) atm\/K \u2014 ce rapport constant confirme le calcul.<\/p>\n<p>\n\r\n<\/section>\n<h2>Comment utiliser le calculateur<\/h2>\n<ol>\n<li>Saisissez la <strong>pression initiale (P\u2081)<\/strong> et choisissez son unit\u00e9 \u2014 atm, kPa, mmHg, bar ou psi.<\/li>\n<li>Saisissez la <strong>temp\u00e9rature initiale (T\u2081)<\/strong> et son unit\u00e9. Les valeurs en \u00b0C ou \u00b0F sont automatiquement converties en kelvins, car la loi exige une temp\u00e9rature absolue.<\/li>\n<li>Dans le menu d\u00e9roulant <strong>Param\u00e8tre \u00e0 calculer<\/strong>, indiquez si l'inconnue est la pression finale ou la temp\u00e9rature finale.<\/li>\n<li>Renseignez l'unique valeur finale que vous connaissez\\u00A0: la <strong>temp\u00e9rature finale (T\u2082)<\/strong> si vous cherchez la pression, ou la <strong>pression finale (P\u2082)<\/strong> si vous cherchez la temp\u00e9rature. Choisissez l'unit\u00e9 d'affichage du r\u00e9sultat.<\/li>\n<li>Lisez les r\u00e9sultats\\u00A0: la valeur finale recherch\u00e9e, le rapport constant \\(P\/T\\) et un d\u00e9tail des calculs montrant chaque conversion et chaque substitution.<\/li>\n<\/ol>\n<h2>Qu'est-ce que la loi de Gay-Lussac\\u00A0?<\/h2>\n<p>La loi de Gay-Lussac \u00e9nonce que la pression exerc\u00e9e par une masse fixe de gaz maintenue \u00e0 volume constant est directement proportionnelle \u00e0 sa temp\u00e9rature absolue. Doubler la temp\u00e9rature en kelvins d'un gaz enferm\u00e9 dans un contenant herm\u00e9tique et rigide double sa pression\\u00A0; la diviser par deux la r\u00e9duit de moiti\u00e9. La loi a \u00e9t\u00e9 formul\u00e9e par le chimiste fran\u00e7ais Joseph Louis Gay-Lussac au d\u00e9but du XIX\u1d49 si\u00e8cle, \u00e0 partir de mesures exp\u00e9rimentales du comportement des gaz chauff\u00e9s dans des r\u00e9cipients clos.<\/p>\n<p>L'explication physique est simple. Dans un contenant rigide, le volume et le nombre de mol\u00e9cules ne changent jamais\\u00A0; la temp\u00e9rature ne peut donc agir sur la pression que par le mouvement des mol\u00e9cules. Chauffer le gaz les acc\u00e9l\u00e8re, si bien qu'elles heurtent les parois plus souvent et plus fort \u2014 ce qui augmente la pression en proportion exacte de la temp\u00e9rature en kelvins.<\/p>\n<p>Tout repose sur la temp\u00e9rature absolue. Les \u00e9chelles Celsius et Fahrenheit sont arbitraires\\u00A0: 20 \u00b0C n'est pas \u00ab\\u00A0deux fois plus chaud\\u00A0\u00bb que 10 \u00b0C. Le kelvin part du z\u00e9ro absolu, si bien que 300 K repr\u00e9sente r\u00e9ellement deux fois l'\u00e9nergie thermique de 150 K. Si vous saisissez une temp\u00e9rature en \u00b0C ou \u00b0F, ce calculateur la convertit en kelvins avant d'appliquer la formule, puis restitue le r\u00e9sultat dans l'unit\u00e9 de votre choix.<\/p>\n<p>Le r\u00e9sultat indique la pression (ou la temp\u00e9rature) atteinte par le gaz apr\u00e8s la transformation. Si la pression finale calcul\u00e9e d\u00e9passe la limite admissible du contenant r\u00e9el, celui-ci peut \u00e9clater \u2014 un risque bien r\u00e9el pour les bombes a\u00e9rosols, les bouteilles de gaz et les enceintes sous pression ferm\u00e9es, et la raison des mentions \u00ab\\u00A0ne pas incin\u00e9rer\\u00A0\u00bb.<\/p>\n<h2>Hypoth\u00e8ses, limites et conseils<\/h2>\n<ul>\n<li><strong>Volume et quantit\u00e9 de gaz constants\\u00A0:<\/strong> la loi ne s'applique qu'\u00e0 un contenant herm\u00e9tique et rigide. Si du gaz s'\u00e9chappe ou si le contenant se dilate, utilisez plut\u00f4t une relation plus g\u00e9n\u00e9rale comme <a href=\"https:\/\/wpcalc.com\/fr\/chimie\/calculateur-equation-van-der-waals\/\">l'\u00e9quation de Van der Waals<\/a>.<\/li>\n<li><strong>Comportement de gaz parfait\\u00A0:<\/strong> la loi est exacte pour un gaz parfait. Les gaz r\u00e9els s'en \u00e9cartent \u00e0 tr\u00e8s haute pression ou pr\u00e8s de leur point de condensation, l\u00e0 o\u00f9 les forces intermol\u00e9culaires et le volume propre des mol\u00e9cules entrent en jeu. Dans la plupart des situations courantes (pressions mod\u00e9r\u00e9es, temp\u00e9ratures bien au-dessus du point d'\u00e9bullition), l'\u00e9cart reste faible.<\/li>\n<li><strong>Aucun changement d'\u00e9tat\\u00A0:<\/strong> le gaz doit rester gazeux. Si la temp\u00e9rature descend assez pour que la substance se condense ou se solidifie, la proportionnalit\u00e9 ne tient plus.<\/li>\n<li><strong>Utilisez la temp\u00e9rature absolue\\u00A0:<\/strong> n'introduisez jamais \u00e0 la main des valeurs en degr\u00e9s Celsius dans la formule \u2014 une valeur nulle ou n\u00e9gative en \u00b0C rend le rapport d\u00e9nu\u00e9 de sens. Ce calculateur fait la conversion pour vous, mais gardez cela en t\u00eate lorsque vous calculez sur papier.<\/li>\n<li><strong>Unit\u00e9s mixtes possibles pour la pression\\u00A0:<\/strong> la formule utilisant un rapport de pressions, \\(P_1\\) et \\(P_2\\) peuvent \u00eatre exprim\u00e9es dans des unit\u00e9s diff\u00e9rentes, \u00e0 condition que le calculateur les convertisse (ce qu'il fait en interne)\\u00A0; les temp\u00e9ratures, elles, doivent toujours \u00eatre absolues.<\/li>\n<\/ul>\n<p>La loi de Gay-Lussac est l'une des lois des gaz o\u00f9 l'on maintient une variable fixe. Si vous \u00e9tudiez le comportement des gaz, le <a href=\"https:\/\/wpcalc.com\/fr\/chimie\/calculateur-loi-graham\/\">calculateur de la loi de Graham<\/a> pour les vitesses d'effusion et le <a href=\"https:\/\/wpcalc.com\/fr\/chimie\/calculateur-equation-van-t-hoff\/\">calculateur de l'\u00e9quation de Van 't Hoff<\/a> pour l'effet de la temp\u00e9rature sur les \u00e9quilibres vous seront \u00e9galement utiles.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Calculez comment la pression d'un gaz varie avec la temp\u00e9rature dans un contenant herm\u00e9tique et rigide gr\u00e2ce \u00e0 la loi de Gay-Lussac. Saisissez la pression et la temp\u00e9rature initiales, ainsi qu'une valeur finale, pour trouver l'autre.<\/p>\n","protected":false},"author":3168,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[17],"tags":[61],"class_list":["post-5754","post","type-post","status-publish","format-standard","hentry","category-chimie","tag-gaz"],"acf":[],"_links":{"self":[{"href":"https:\/\/wpcalc.com\/fr\/wp-json\/wp\/v2\/posts\/5754","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wpcalc.com\/fr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/wpcalc.com\/fr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/wpcalc.com\/fr\/wp-json\/wp\/v2\/users\/3168"}],"replies":[{"embeddable":true,"href":"https:\/\/wpcalc.com\/fr\/wp-json\/wp\/v2\/comments?post=5754"}],"version-history":[{"count":1,"href":"https:\/\/wpcalc.com\/fr\/wp-json\/wp\/v2\/posts\/5754\/revisions"}],"predecessor-version":[{"id":5944,"href":"https:\/\/wpcalc.com\/fr\/wp-json\/wp\/v2\/posts\/5754\/revisions\/5944"}],"wp:attachment":[{"href":"https:\/\/wpcalc.com\/fr\/wp-json\/wp\/v2\/media?parent=5754"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wpcalc.com\/fr\/wp-json\/wp\/v2\/categories?post=5754"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wpcalc.com\/fr\/wp-json\/wp\/v2\/tags?post=5754"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}