{"id":189819,"date":"2025-02-10T13:52:07","date_gmt":"2025-02-10T13:52:07","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=189819"},"modified":"2025-02-10T13:52:09","modified_gmt":"2025-02-10T13:52:09","slug":"the-standard-molar-enthalpy-of-formation-of-nh3g-is-45-9-kj-mol","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/02\/10\/the-standard-molar-enthalpy-of-formation-of-nh3g-is-45-9-kj-mol\/","title":{"rendered":"The standard molar enthalpy of formation of NH3(g) is 45.9 kJ\/mol"},"content":{"rendered":"\n<p>The standard molar enthalpy of formation of NH3(g) is 45.9 kJ\/mol. What is the enthalpy change if  9.10 g N2(g) and 1.82  g H2(g) react to produce NH3(g)?<\/p>\n\n\n\n<p><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-ast-global-color-6-color\"><strong>The Correct Answer and Explanation is :<\/strong><\/mark><\/p>\n\n\n\n<p>To find the enthalpy change for the reaction where 9.10 g of N\u2082(g) and 1.82 g of H\u2082(g) react to produce NH\u2083(g), we first need to write the balanced chemical equation for the reaction:<\/p>\n\n\n\n<p>[<br>N_2(g) + 3H_2(g) \\rightarrow 2NH_3(g)<br>]<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Step 1: Convert the masses of N\u2082 and H\u2082 to moles<\/h3>\n\n\n\n<p>To calculate the moles of each reactant, we use the molar masses of N\u2082 and H\u2082.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Molar mass of N\u2082 = 28.02 g\/mol<\/li>\n\n\n\n<li>Molar mass of H\u2082 = 2.02 g\/mol<\/li>\n<\/ul>\n\n\n\n<p>For N\u2082:<\/p>\n\n\n\n<p>[<br>\\text{Moles of } N_2 = \\frac{9.10 \\, \\text{g}}{28.02 \\, \\text{g\/mol}} = 0.325 \\, \\text{mol}<br>]<\/p>\n\n\n\n<p>For H\u2082:<\/p>\n\n\n\n<p>[<br>\\text{Moles of } H_2 = \\frac{1.82 \\, \\text{g}}{2.02 \\, \\text{g\/mol}} = 0.901 \\, \\text{mol}<br>]<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Step 2: Determine the limiting reagent<\/h3>\n\n\n\n<p>From the balanced equation, we see that 1 mole of N\u2082 reacts with 3 moles of H\u2082 to produce 2 moles of NH\u2083. Therefore, we can compare the mole ratios to identify the limiting reagent.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>For 0.325 mol of N\u2082, we would need ( 0.325 \\, \\text{mol} \\times 3 = 0.975 \\, \\text{mol} ) of H\u2082.<\/li>\n\n\n\n<li>We only have 0.901 mol of H\u2082, which is less than 0.975 mol. Thus, H\u2082 is the limiting reagent.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Step 3: Calculate the moles of NH\u2083 produced<\/h3>\n\n\n\n<p>From the balanced equation, 3 moles of H\u2082 produce 2 moles of NH\u2083. Therefore, 0.901 mol of H\u2082 will produce:<\/p>\n\n\n\n<p>[<br>\\text{Moles of NH\u2083} = \\frac{2}{3} \\times 0.901 \\, \\text{mol} = 0.601 \\, \\text{mol}<br>]<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Step 4: Calculate the enthalpy change<\/h3>\n\n\n\n<p>The standard molar enthalpy of formation of NH\u2083(g) is -45.9 kJ\/mol. The enthalpy change for the reaction is:<\/p>\n\n\n\n<p>[<br>\\Delta H = \\text{moles of NH\u2083} \\times \\Delta H_f^\\circ(\\text{NH\u2083}) = 0.601 \\, \\text{mol} \\times (-45.9 \\, \\text{kJ\/mol}) = -27.6 \\, \\text{kJ}<br>]<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Conclusion<\/h3>\n\n\n\n<p>The enthalpy change for the reaction is -27.6 kJ. This means that the reaction releases 27.6 kJ of energy when 9.10 g of N\u2082 and 1.82 g of H\u2082 react to form NH\u2083.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>The standard molar enthalpy of formation of NH3(g) is 45.9 kJ\/mol. What is the enthalpy change if 9.10 g N2(g) and 1.82 g H2(g) react to produce NH3(g)? The Correct Answer and Explanation is : To find the enthalpy change for the reaction where 9.10 g of N\u2082(g) and 1.82 g of H\u2082(g) react to [&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-189819","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/189819","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=189819"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/189819\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=189819"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=189819"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=189819"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}