{"id":257838,"date":"2025-07-17T17:49:12","date_gmt":"2025-07-17T17:49:12","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=257838"},"modified":"2025-07-17T17:49:19","modified_gmt":"2025-07-17T17:49:19","slug":"the-molar-enthalpy-of-dissolution-of-sodium-iodide-is-7-61-kj-mol-nai-as-shown-below","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/07\/17\/the-molar-enthalpy-of-dissolution-of-sodium-iodide-is-7-61-kj-mol-nai-as-shown-below\/","title":{"rendered":"The molar enthalpy of dissolution of sodium iodide is 7.61 kJ\/mol NaI as shown below"},"content":{"rendered":"\n<p>The molar enthalpy of dissolution of sodium iodide is 7.61 kJ\/mol NaI as shown below: NaI(s) \u00e2\u2020\u2019 Na+ (aq) + I- (aq) \u00e2\u02c6\u2020H = +7.61 kJ\/mol A 35.7 g sample of NaI is dissolved in 50.0 g of water in a calorimeter at 21.5\u00c2\u00b0C. The final temperature of the solution is __<\/p>\n\n\n\n<p><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-ast-global-color-0-color\">The Correct Answer and Explanation is:<\/mark><\/strong><\/p>\n\n\n\n<p>To solve this problem, we will need to use the concept of heat transfer during the dissolution process and apply the principle of conservation of energy. The heat absorbed by the water will equal the heat released by the dissolution of sodium iodide. Here&#8217;s how we can break it down:<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Given Data:<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Molar enthalpy of dissolution (\u0394Hdissolution\\Delta H_{\\text{dissolution}}\u0394Hdissolution\u200b) = 7.61 kJ\/mol<\/li>\n\n\n\n<li>Mass of NaI = 35.7 g<\/li>\n\n\n\n<li>Mass of water = 50.0 g<\/li>\n\n\n\n<li>Initial temperature of the solution = 21.5\u00b0C<\/li>\n\n\n\n<li>Final temperature of the solution = unknown<\/li>\n\n\n\n<li>Specific heat capacity of water (cwaterc_{\\text{water}}cwater\u200b) = 4.18 J\/g\u00b0C<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Step 1: Convert the mass of NaI to moles<\/h3>\n\n\n\n<p>To find how many moles of NaI are dissolving, we need the molar mass of NaI:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Molar mass of NaI = Na (22.99 g\/mol) + I (126.90 g\/mol) = 149.89 g\/mol<\/li>\n\n\n\n<li>Moles of NaI = Mass of NaI \/ Molar mass of NaI = 35.7 g \/ 149.89 g\/mol = 0.238 mol<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Step 2: Calculate the heat released during dissolution<\/h3>\n\n\n\n<p>The heat released during the dissolution of NaI is given by: qdissolution=moles&nbsp;of&nbsp;NaI\u00d7\u0394Hdissolutionq_{\\text{dissolution}} = \\text{moles of NaI} \\times \\Delta H_{\\text{dissolution}}qdissolution\u200b=moles&nbsp;of&nbsp;NaI\u00d7\u0394Hdissolution\u200b qdissolution=0.238\u2009mol\u00d77.61\u2009kJ\/mol=1.81\u2009kJ=1810\u2009Jq_{\\text{dissolution}} = 0.238 \\, \\text{mol} \\times 7.61 \\, \\text{kJ\/mol} = 1.81 \\, \\text{kJ} = 1810 \\, \\text{J}qdissolution\u200b=0.238mol\u00d77.61kJ\/mol=1.81kJ=1810J<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Step 3: Calculate the temperature change of the water<\/h3>\n\n\n\n<p>Now, we will calculate the temperature change of the water based on the heat absorbed. The heat absorbed by the water is: qwater=mwater\u00d7cwater\u00d7\u0394Tq_{\\text{water}} = m_{\\text{water}} \\times c_{\\text{water}} \\times \\Delta Tqwater\u200b=mwater\u200b\u00d7cwater\u200b\u00d7\u0394T<\/p>\n\n\n\n<p>where:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>mwater=50.0\u2009gm_{\\text{water}} = 50.0 \\, \\text{g}mwater\u200b=50.0g<\/li>\n\n\n\n<li>cwater=4.18\u2009J\/g\u00b0Cc_{\\text{water}} = 4.18 \\, \\text{J\/g\u00b0C}cwater\u200b=4.18J\/g\u00b0C<\/li>\n\n\n\n<li>\u0394T\\Delta T\u0394T is the change in temperature (final temperature minus initial temperature)<\/li>\n<\/ul>\n\n\n\n<p>Rearranging the equation to solve for \u0394T\\Delta T\u0394T: \u0394T=qwatermwater\u00d7cwater\\Delta T = \\frac{q_{\\text{water}}}{m_{\\text{water}} \\times c_{\\text{water}}}\u0394T=mwater\u200b\u00d7cwater\u200bqwater\u200b\u200b \u0394T=1810\u2009J50.0\u2009g\u00d74.18\u2009J\/g\u00b0C=1810209\u22488.65\u00b0C\\Delta T = \\frac{1810 \\, \\text{J}}{50.0 \\, \\text{g} \\times 4.18 \\, \\text{J\/g\u00b0C}} = \\frac{1810}{209} \\approx 8.65\u00b0C\u0394T=50.0g\u00d74.18J\/g\u00b0C1810J\u200b=2091810\u200b\u22488.65\u00b0C<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Step 4: Calculate the final temperature of the solution<\/h3>\n\n\n\n<p>The initial temperature of the solution is 21.5\u00b0C. The final temperature will be: Tfinal=Tinitial+\u0394TT_{\\text{final}} = T_{\\text{initial}} + \\Delta TTfinal\u200b=Tinitial\u200b+\u0394T Tfinal=21.5\u00b0C+8.65\u00b0C=30.15\u00b0CT_{\\text{final}} = 21.5\u00b0C + 8.65\u00b0C = 30.15\u00b0CTfinal\u200b=21.5\u00b0C+8.65\u00b0C=30.15\u00b0C<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Final Answer:<\/h3>\n\n\n\n<p>The final temperature of the solution is approximately <strong>30.2\u00b0C<\/strong>.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" src=\"https:\/\/learnexams.com\/blog\/wp-content\/uploads\/2025\/07\/learnexams-banner6-835.jpeg\" alt=\"\" class=\"wp-image-257840\"\/><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>The molar enthalpy of dissolution of sodium iodide is 7.61 kJ\/mol NaI as shown below: NaI(s) \u00e2\u2020\u2019 Na+ (aq) + I- (aq) \u00e2\u02c6\u2020H = +7.61 kJ\/mol A 35.7 g sample of NaI is dissolved in 50.0 g of water in a calorimeter at 21.5\u00c2\u00b0C. The final temperature of the solution is __ The Correct Answer [&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-257838","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/257838","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=257838"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/257838\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=257838"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=257838"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=257838"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}