{"id":7142,"date":"2023-10-24T12:08:57","date_gmt":"2023-10-24T10:08:57","guid":{"rendered":"https:\/\/www.em-grade.com\/sin-categorizar\/peso-molecular-pm-mw-y-fw\/"},"modified":"2025-05-16T12:18:07","modified_gmt":"2025-05-16T10:18:07","slug":"peso-molecular-pm-mw-y-fw","status":"publish","type":"post","link":"https:\/\/www.em-grade.com\/es\/definiciones-quimica\/peso-molecular-pm-mw-y-fw\/","title":{"rendered":"Peso molecular: PM, MW y FW"},"content":{"rendered":"<h4><strong>\u00bfQu\u00e9 es el peso molecular (PM)?<\/strong><\/h4>\n<p>El <strong>peso molecular<\/strong> (PM) es la masa de un mol de una entidad qu\u00edmica (mol\u00e9cula, ion, etc.). En la pr\u00e1ctica, el PM equivale a la <strong>suma de las masas at\u00f3micas<\/strong> de todos los \u00e1tomos presentes en una mol\u00e9cula.<\/p>\n<ul>\n<li><strong>Unidad principal:<\/strong> dalton (Da) o unidad de masa at\u00f3mica (u o a.m.u)<\/li>\n<li><strong>Conversi\u00f3n clave:<\/strong><br \/>\n1 a.m.u = 1 Da = 1 g\u00b7mol\u207b\u00b9<\/li>\n<\/ul>\n<p>\u2697\ufe0f El valor del PM siempre figura en los frascos de compuestos en polvo en los laboratorios. <strong>Es imprescindible para preparar soluciones con una concentraci\u00f3n precisa<\/strong> (molaridad).<\/p>\n<hr \/>\n<h4><strong>Acr\u00f3nimos del peso molecular: PM, MW y FW<\/strong><\/h4>\n<p>Seg\u00fan el idioma y el contexto, el peso molecular puede abreviarse de diversas formas:<\/p>\n<ul>\n<li><strong>PM<\/strong>: Peso Molecular (espa\u00f1ol)<\/li>\n<li><strong>MW<\/strong>: Molecular Weight (ingl\u00e9s)<\/li>\n<li><strong>FW<\/strong>: Formula Weight (ingl\u00e9s, para compuestos con f\u00f3rmula general\u2014por ejemplo, hidratados)<\/li>\n<\/ul>\n<p><strong>Nota:<\/strong> FW suele utilizarse para sales o mol\u00e9culas hidratadas cuyo peso incluye el de las mol\u00e9culas de agua.<\/p>\n<hr \/>\n<h4><strong>\u00bfPara qu\u00e9 sirve el peso molecular?<\/strong><\/h4>\n<p>El peso molecular es <strong>fundamental<\/strong> para:<\/p>\n<ul>\n<li>Convertir una cantidad de sustancia (mol) a masa (gramos)<\/li>\n<li>Preparar soluciones a una concentraci\u00f3n determinada (c\u00e1lculos de molaridad)<\/li>\n<li>Entender y predecir reacciones qu\u00edmicas (rendimientos, dosificaciones\u2026)<\/li>\n<\/ul>\n<hr \/>\n<h4><strong>Diferencia entre peso molecular y masa molar<\/strong><\/h4>\n<p>Estos dos conceptos est\u00e1n <strong>estrechamente relacionados<\/strong>:<\/p>\n<ul>\n<li><strong>Peso molecular<\/strong> = n\u00famero puro (ej.: 98,08 para H\u2082SO\u2084)<\/li>\n<li><strong>Masa molar (M)<\/strong> = expresada en g\u00b7mol\u207b\u00b9 (ej.: 98,08 g\u00b7mol\u207b\u00b9)<\/li>\n<li><strong>Uso:<\/strong> En la pr\u00e1ctica, ambos t\u00e9rminos se emplean casi de forma intercambiable, aunque la masa molar refiere espec\u00edficamente a la relaci\u00f3n masa\/cantidad de sustancia.<\/li>\n<\/ul>\n<hr \/>\n<h4><strong>\u00bfC\u00f3mo calcular el peso molecular? (v\u00eddeo)<\/strong><\/h4>\n<p>Para ilustrar el c\u00e1lculo del PM, consulta este v\u00eddeo educativo (en ingl\u00e9s) de TheChemistryNinja:<\/p>\n<p><iframe loading=\"lazy\" title=\"How to Calculate Molecular Weight from a Chemical Formula\" width=\"1080\" height=\"810\" src=\"https:\/\/www.youtube.com\/embed\/XonYVIQ7atg?feature=oembed&#038;enablejsapi=1&#038;origin=https:\/\/www.em-grade.com\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe><\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u00bfQu\u00e9 es el peso molecular (PM)? El peso molecular (PM) es la masa de un mol de una entidad qu\u00edmica (mol\u00e9cula, ion, etc.). En la pr\u00e1ctica, el PM equivale a&#8230;<\/p>\n","protected":false},"author":8,"featured_media":7143,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_seopress_titles_title":"","_seopress_titles_desc":"","_seopress_robots_index":"","_seopress_robots_follow":"","_seopress_robots_imageindex":"","_seopress_robots_snippet":"","_seopress_robots_primary_cat":"","_seopress_robots_breadcrumbs":"","_seopress_robots_freeze_modified_date":"","_seopress_robots_custom_modified_date":"","_seopress_robots_canonical":"","_seopress_social_fb_title":"","_seopress_social_fb_desc":"","_seopress_social_fb_img":"","_seopress_social_fb_img_attachment_id":0,"_seopress_social_fb_img_width":0,"_seopress_social_fb_img_height":0,"_seopress_social_twitter_title":"","_seopress_social_twitter_desc":"","_seopress_social_twitter_img":"","_seopress_social_twitter_img_attachment_id":0,"_seopress_social_twitter_img_width":0,"_seopress_social_twitter_img_height":0,"_seopress_redirections_value":"","_seopress_redirections_enabled":"","_seopress_redirections_enabled_regex":"","_seopress_redirections_logged_status":"","_seopress_redirections_param":"","_seopress_redirections_type":0,"_seopress_analysis_target_kw":"","_seopress_news_disabled":"","_seopress_video_disabled":"","_seopress_video":[],"_seopress_pro_schemas_manual":[],"_seopress_pro_rich_snippets_disable_all":"","_seopress_pro_rich_snippets_disable":[],"_seopress_pro_schemas":[],"itsec_x_frame_options":"","footnotes":""},"categories":[453],"tags":[645],"class_list":["post-7142","post","type-post","status-publish","format-standard","has-post-thumbnail","category-definiciones-quimica","tag-fw-pm-es"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.em-grade.com\/es\/wp-json\/wp\/v2\/posts\/7142","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.em-grade.com\/es\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.em-grade.com\/es\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.em-grade.com\/es\/wp-json\/wp\/v2\/users\/8"}],"replies":[{"embeddable":true,"href":"https:\/\/www.em-grade.com\/es\/wp-json\/wp\/v2\/comments?post=7142"}],"version-history":[{"count":2,"href":"https:\/\/www.em-grade.com\/es\/wp-json\/wp\/v2\/posts\/7142\/revisions"}],"predecessor-version":[{"id":11096,"href":"https:\/\/www.em-grade.com\/es\/wp-json\/wp\/v2\/posts\/7142\/revisions\/11096"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.em-grade.com\/es\/wp-json\/wp\/v2\/media\/7143"}],"wp:attachment":[{"href":"https:\/\/www.em-grade.com\/es\/wp-json\/wp\/v2\/media?parent=7142"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.em-grade.com\/es\/wp-json\/wp\/v2\/categories?post=7142"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.em-grade.com\/es\/wp-json\/wp\/v2\/tags?post=7142"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}