{"id":192988,"date":"2025-02-18T18:11:01","date_gmt":"2025-02-18T18:11:01","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=192988"},"modified":"2025-02-18T18:11:03","modified_gmt":"2025-02-18T18:11:03","slug":"the-normal-freezing-point-of-ammonia-is-78-degrees-celsius","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/02\/18\/the-normal-freezing-point-of-ammonia-is-78-degrees-celsius\/","title":{"rendered":"The normal freezing point of ammonia is -78 degrees celsius"},"content":{"rendered":"\n<p>The normal freezing point of ammonia is -78 degrees celsius. Predict the signs of Delta H, Delta S, and Delta G for ammonia when it freezes at -80 degrees celsius and 1 atm: NH3 (l) &#8212;&gt; NH3 (s)<\/p>\n\n\n\n<p><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-ast-global-color-6-color\">The correct answer and explanation is:<\/mark><\/strong><\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Answer:<\/h3>\n\n\n\n<p>For the freezing of ammonia at \u221280\u2218C-80^\\circ C and 1 atm: NH3(l)\u2192NH3(s)NH_3 (l) \\rightarrow NH_3 (s)<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>\u0394H (Enthalpy Change):<\/strong> <strong>Negative (-)<\/strong><\/li>\n\n\n\n<li><strong>\u0394S (Entropy Change):<\/strong> <strong>Negative (-)<\/strong><\/li>\n\n\n\n<li><strong>\u0394G (Gibbs Free Energy Change):<\/strong> <strong>Negative (-)<\/strong><\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Explanation:<\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u0394H (Enthalpy Change, Heat Released or Absorbed)<\/strong>\n<ul class=\"wp-block-list\">\n<li>Freezing is an <strong>exothermic<\/strong> process, meaning heat is released as the liquid transitions to a solid. The molecules slow down and lose kinetic energy.<\/li>\n\n\n\n<li>Since energy is leaving the system, <strong>\u0394H is negative<\/strong>.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>\u0394S (Entropy Change, Disorder of the System)<\/strong>\n<ul class=\"wp-block-list\">\n<li>Entropy (SS) represents the level of disorder or randomness in a system.<\/li>\n\n\n\n<li>A liquid has more disorder (higher entropy) compared to a solid because molecules in the liquid state can move more freely.<\/li>\n\n\n\n<li>When ammonia freezes, the molecules become more ordered in the solid phase.<\/li>\n\n\n\n<li>Since the system becomes more ordered, <strong>\u0394S is negative<\/strong>.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>\u0394G (Gibbs Free Energy Change, Spontaneity of the Process)<\/strong>\n<ul class=\"wp-block-list\">\n<li>The Gibbs free energy equation is: \u0394G=\u0394H\u2212T\u0394S\\Delta G = \\Delta H &#8211; T\\Delta S<\/li>\n\n\n\n<li>At the normal freezing point (\u221278\u2218C-78^\\circ C), <strong>\u0394G is zero<\/strong> because the system is at equilibrium.<\/li>\n\n\n\n<li>Here, ammonia is freezing at \u221280\u2218C-80^\\circ C, which is below its normal freezing point. This means the surroundings are colder, favoring the freezing process.<\/li>\n\n\n\n<li>Since freezing is <strong>spontaneous<\/strong> under these conditions, <strong>\u0394G is negative<\/strong>.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p><strong>Conclusion:<\/strong><br>Since the temperature is below the normal freezing point, ammonia will freeze spontaneously. The process releases heat (negative \u0394H), decreases entropy (negative \u0394S), and is thermodynamically favored (negative \u0394G).<\/p>\n\n\n\n<p>Now, I&#8217;ll generate an image illustrating this freezing process.<\/p>\n\n\n\n<p>Here is the generated scientific illustration showing the phase transition of ammonia (NH\u2083) from liquid to solid at -80\u00b0C. It depicts the molecules becoming more structured as ammonia freezes, releasing heat in the process. Let me know if you need any modifications!<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" src=\"https:\/\/learnexams.com\/blog\/wp-content\/uploads\/2025\/02\/image-950.png\" alt=\"\" class=\"wp-image-192989\"\/><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>The normal freezing point of ammonia is -78 degrees celsius. Predict the signs of Delta H, Delta S, and Delta G for ammonia when it freezes at -80 degrees celsius and 1 atm: NH3 (l) &#8212;&gt; NH3 (s) The correct answer and explanation is: Answer: For the freezing of ammonia at \u221280\u2218C-80^\\circ C and 1 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[25],"tags":[],"class_list":["post-192988","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/192988","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/comments?post=192988"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/192988\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=192988"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=192988"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=192988"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}