{"id":2602,"date":"2016-08-24T13:51:14","date_gmt":"2016-08-24T13:51:14","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/?post_type=chapter&#038;p=2602"},"modified":"2017-08-28T21:57:41","modified_gmt":"2017-08-28T21:57:41","slug":"melting-point","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/chapter\/melting-point\/","title":{"raw":"Melting Point","rendered":"Melting Point"},"content":{"raw":"<div class=\"x-ck12-data-objectives\">\r\n<div class=\"textbox learning-objectives\">\r\n<h3>Learning Objectives<\/h3>\r\n<ul>\r\n \t<li>Define melting point.<\/li>\r\n \t<li>Describe the process of particle movement in melting.<\/li>\r\n \t<li>Describe the forces that influence the melting point of a material.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<\/div>\r\n<div class=\"textbox examples\">\r\n<h3>Examples<\/h3>\r\n<p id=\"x-ck12-YmE1OWQ1YTM0MTczZTNkZWNjMzE5ZTM5MzIwN2Y1YWM.-ut5\"><span class=\"x-ck12-img-inline\"><img src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/53\/2014\/08\/19212039\/20140811155425630582.jpeg\" alt=\"When ice melts, it turns from solid to liquid\" width=\"400\" \/><\/span><\/p>\r\n\r\n<h4><span class=\"x-ck12-img-inline\">Have you ever gone ice skating?\r\n<\/span><\/h4>\r\n<p id=\"x-ck12-ZjdmY2MyMDAwNzczY2FiNGRlZjQ2ZGFmODFjYzM1MzY.-dsf\">In the winter, many people find the snow and ice beautiful. They enjoy getting out to ski or ice-skate. Others don\u2019t find that time of year to be so much fun. When the snow melts, the roads get very sloppy and messy. Those people look forward to spring when all the ice and snow are gone and the weather is warmer.<\/p>\r\n\r\n<\/div>\r\n<h3>Melting Point<\/h3>\r\n<p id=\"x-ck12-NWIzYTg1ODEwM2M0ZDk2MmM1M2FkZGI1NDAzZjE4NTQ.-lo5\">Solids are similar to liquids in that both are condensed states, with particles that are far closer together than those of a gas. However, while liquids are fluid, solids are not. The particles of most solids are packed tightly together in an orderly arrangement. The motion of individual atoms, ions, or molecules in a solid is restricted to <strong>vibrational motion <\/strong>about a fixed point. Solids are almost completely <strong>incompressible <\/strong>and are the densest of the three states of matter.<\/p>\r\n<p id=\"x-ck12-MWFhMWZhZTFjNzIzNjZmYzQwZDVkMWY4YjNjMzQwMzc.-7og\">As a solid is heated, its particles vibrate more rapidly as the solid absorbs kinetic energy. Eventually, the organization of the particles within the solid structure begins to break down and the solid starts to melt. The <strong>melting point <\/strong>is the temperature at which a solid changes into a liquid. At its melting point, the disruptive vibrations of the particles of the solid overcome the attractive forces operating within the solid. As with boiling points, the melting point of a solid is dependent on the strength of those attractive forces. Sodium chloride (NaCl) is an ionic compound that consists of a multitude of strong ionic bonds. Sodium chloride melts at 801\u00b0C. Ice (solid H <sub>2 <\/sub>O) is a molecular compound whose molecules are held together by hydrogen bonds. Though hydrogen bonds are the strongest of the intermolecular forces, the strength of hydrogen bonds is much less than that of ionic bonds. The melting point of ice is 0\u00b0C.<\/p>\r\n<p id=\"x-ck12-N2NjZWEzNWM2ZDQ4NjIwZmYxYWZlMjlhMTI4MGMwY2E.-htc\">The melting point of a solid is the same as the freezing point of the liquid. At that temperature, the solid and liquid states of the substance are in equilibrium. For water, this equilibrium occurs at 0\u00b0C.<\/p>\r\n<p id=\"x-ck12-2eq\" class=\"x-ck12-indent\"><img class=\"x-ck12-block-math\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/53\/2014\/08\/19212040\/ad43cf86fc8e24a0de9a1b5ba21c0a74.png\" alt=\"text{H}_2text{O}text{(s)} rightleftarrows text{H}_2text{O}text{(l)}\" width=\"137\" height=\"18\" \/><\/p>\r\n<p id=\"x-ck12-ODQ4ODMxZTliNjNjZTdjYWM0ZWVhNTk5MTEwOTk0N2I.-xv3\">We tend to think of solids as those materials that are solid at room temperature. However, all materials have melting points of some sort. Gases become solids at extremely low temperatures, and liquids will also become solid if the temperature is low enough. The <strong>Table <\/strong>below gives the melting points of some common materials.<\/p>\r\n\r\n<table id=\"x-ck12-MjljOTg2YzQ1YTJjYmZmYmYyNmU2MzIzNDAxOGJkMjA.-r97\" class=\"x-ck12-nofloat\" border=\"1\"><caption>Melting Points of Common Materials<\/caption>\r\n<tbody>\r\n<tr>\r\n<td><strong>Material<\/strong><\/td>\r\n<td><strong>Melting Point (\u00b0C)<\/strong><\/td>\r\n<\/tr>\r\n<tr>\r\n<td>hydrogen<\/td>\r\n<td>-259<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>oxygen<\/td>\r\n<td>-219<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>diethyl ether<\/td>\r\n<td>-116<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>ethanol<\/td>\r\n<td>-114<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>water<\/td>\r\n<td>\u00a00<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>pure silver<\/td>\r\n<td>961<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>pure gold<\/td>\r\n<td>1063<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>iron<\/td>\r\n<td>1538<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n<div class=\"textbox key-takeaways\">\r\n<h3>Summary<\/h3>\r\n<ul id=\"x-ck12-OTdmMTgwNWE5MjU3ZWEyNGVkYjM4MTg0ODhkNTBlYTE.-rsx\">\r\n \t<li>The melting point is the temperature at which a solid changes into a liquid.<\/li>\r\n \t<li>Intermolecular forces have a strong influence on melting point.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<div class=\"textbox exercises\">\r\n<h3>Practice<\/h3>\r\n<p id=\"x-ck12-Y2JlMjQ5M2YzMTNmNmRjMzNmZTI0MTMzYzcwM2IzZmY.-s31\">Use the link below to answer the following questions<\/p>\r\n<p id=\"x-ck12-ODhjNDZlMzEwNmQ0YTljOGNhOTM1ZGFkYzZiMTFkNDA.-yfr\"><a href=\"http:\/\/chemwiki.ucdavis.edu\/Organic_Chemistry\/Organic_Chemistry_With_a_Biological_Emphasis\/Chapter__2%3a_Introduction_to_organic_structure_and_bonding_II\/Section_2.4%3a_Solubility%2c_melting_points_and_boiling_points\">http:\/\/chemwiki.ucdavis.edu\/Organic_Chemistry\/Organic_Chemistry_With_a_Biological_Emphasis\/Chapter__2%3a_Introduction_to_organic_structure_and_bonding_II\/Section_2.4%3a_Solubility%2c_melting_points_and_boiling_points<\/a><\/p>\r\n\r\n<ol id=\"x-ck12-ODM4NjZkODY1MjA3YzRjZjI2OGRlZWI2ZDM5ZTc3ZmU.-8qn\">\r\n \t<li>To what degree of accuracy can melting points be measured?<\/li>\r\n \t<li>How can we use melting point data to help identify a compound?<\/li>\r\n \t<li>How can we use melting points to assess the purity of a compound?<\/li>\r\n<\/ol>\r\n<\/div>\r\n<div class=\"textbox exercises\">\r\n<h3>Review<\/h3>\r\n<ol id=\"x-ck12-OTM0OWE5NTliOTZkMzY5OTgxZDI4ZGY5NzcxNmE1ODA.-sr0\">\r\n \t<li>Define melting point.<\/li>\r\n \t<li>What happens when a material melts?<\/li>\r\n \t<li>Would you expect ethane (C <sub>2 <\/sub>H <sub>6 <\/sub>) to have a higher or lower melting point than water? Explain your answer.<\/li>\r\n<\/ol>\r\n<\/div>\r\n<div class=\"x-ck12-data-problem-set\">\r\n<div class=\"textbox learning-objectives\">\r\n<h3>Glossary<\/h3>\r\n<div class=\"x-ck12-data-vocabulary\">\r\n<ul id=\"x-ck12-MzY4NmQ3ZjI5ZjU0ZDM1YjM3NmIyZDQ2ODRkOGE0NmM.-vum\">\r\n \t<li><strong>incompressible: <\/strong>Unable to be compressed.<\/li>\r\n \t<li><strong>melting point: <\/strong>The temperature at which a solid changes into a liquid.<\/li>\r\n \t<li><strong>vibrational motion: <\/strong>Back and forth movement.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n[reveal-answer q=\"836080\"]Show References[\/reveal-answer]\r\n[hidden-answer a=\"836080\"]\r\n<h2>References<\/h2>\r\n<ol>\r\n \t<li>Jonas Bergsten (Wikimedia: Bergsten). <a href=\"http:\/\/commons.wikimedia.org\/wiki\/File:Drop_of_water_2003_05.jpg\">http:\/\/commons.wikimedia.org\/wiki\/File:Drop_of_water_2003_05.jpg <\/a>.<\/li>\r\n<\/ol>\r\n[\/hidden-answer]","rendered":"<div class=\"x-ck12-data-objectives\">\n<div class=\"textbox learning-objectives\">\n<h3>Learning Objectives<\/h3>\n<ul>\n<li>Define melting point.<\/li>\n<li>Describe the process of particle movement in melting.<\/li>\n<li>Describe the forces that influence the melting point of a material.<\/li>\n<\/ul>\n<\/div>\n<\/div>\n<div class=\"textbox examples\">\n<h3>Examples<\/h3>\n<p id=\"x-ck12-YmE1OWQ1YTM0MTczZTNkZWNjMzE5ZTM5MzIwN2Y1YWM.-ut5\"><span class=\"x-ck12-img-inline\"><img decoding=\"async\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/53\/2014\/08\/19212039\/20140811155425630582.jpeg\" alt=\"When ice melts, it turns from solid to liquid\" width=\"400\" \/><\/span><\/p>\n<h4><span class=\"x-ck12-img-inline\">Have you ever gone ice skating?<br \/>\n<\/span><\/h4>\n<p id=\"x-ck12-ZjdmY2MyMDAwNzczY2FiNGRlZjQ2ZGFmODFjYzM1MzY.-dsf\">In the winter, many people find the snow and ice beautiful. They enjoy getting out to ski or ice-skate. Others don\u2019t find that time of year to be so much fun. When the snow melts, the roads get very sloppy and messy. Those people look forward to spring when all the ice and snow are gone and the weather is warmer.<\/p>\n<\/div>\n<h3>Melting Point<\/h3>\n<p id=\"x-ck12-NWIzYTg1ODEwM2M0ZDk2MmM1M2FkZGI1NDAzZjE4NTQ.-lo5\">Solids are similar to liquids in that both are condensed states, with particles that are far closer together than those of a gas. However, while liquids are fluid, solids are not. The particles of most solids are packed tightly together in an orderly arrangement. The motion of individual atoms, ions, or molecules in a solid is restricted to <strong>vibrational motion <\/strong>about a fixed point. Solids are almost completely <strong>incompressible <\/strong>and are the densest of the three states of matter.<\/p>\n<p id=\"x-ck12-MWFhMWZhZTFjNzIzNjZmYzQwZDVkMWY4YjNjMzQwMzc.-7og\">As a solid is heated, its particles vibrate more rapidly as the solid absorbs kinetic energy. Eventually, the organization of the particles within the solid structure begins to break down and the solid starts to melt. The <strong>melting point <\/strong>is the temperature at which a solid changes into a liquid. At its melting point, the disruptive vibrations of the particles of the solid overcome the attractive forces operating within the solid. As with boiling points, the melting point of a solid is dependent on the strength of those attractive forces. Sodium chloride (NaCl) is an ionic compound that consists of a multitude of strong ionic bonds. Sodium chloride melts at 801\u00b0C. Ice (solid H <sub>2 <\/sub>O) is a molecular compound whose molecules are held together by hydrogen bonds. Though hydrogen bonds are the strongest of the intermolecular forces, the strength of hydrogen bonds is much less than that of ionic bonds. The melting point of ice is 0\u00b0C.<\/p>\n<p id=\"x-ck12-N2NjZWEzNWM2ZDQ4NjIwZmYxYWZlMjlhMTI4MGMwY2E.-htc\">The melting point of a solid is the same as the freezing point of the liquid. At that temperature, the solid and liquid states of the substance are in equilibrium. For water, this equilibrium occurs at 0\u00b0C.<\/p>\n<p id=\"x-ck12-2eq\" class=\"x-ck12-indent\"><img loading=\"lazy\" decoding=\"async\" class=\"x-ck12-block-math\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/53\/2014\/08\/19212040\/ad43cf86fc8e24a0de9a1b5ba21c0a74.png\" alt=\"text{H}_2text{O}text{(s)} rightleftarrows text{H}_2text{O}text{(l)}\" width=\"137\" height=\"18\" \/><\/p>\n<p id=\"x-ck12-ODQ4ODMxZTliNjNjZTdjYWM0ZWVhNTk5MTEwOTk0N2I.-xv3\">We tend to think of solids as those materials that are solid at room temperature. However, all materials have melting points of some sort. Gases become solids at extremely low temperatures, and liquids will also become solid if the temperature is low enough. The <strong>Table <\/strong>below gives the melting points of some common materials.<\/p>\n<table id=\"x-ck12-MjljOTg2YzQ1YTJjYmZmYmYyNmU2MzIzNDAxOGJkMjA.-r97\" class=\"x-ck12-nofloat\">\n<caption>Melting Points of Common Materials<\/caption>\n<tbody>\n<tr>\n<td><strong>Material<\/strong><\/td>\n<td><strong>Melting Point (\u00b0C)<\/strong><\/td>\n<\/tr>\n<tr>\n<td>hydrogen<\/td>\n<td>-259<\/td>\n<\/tr>\n<tr>\n<td>oxygen<\/td>\n<td>-219<\/td>\n<\/tr>\n<tr>\n<td>diethyl ether<\/td>\n<td>-116<\/td>\n<\/tr>\n<tr>\n<td>ethanol<\/td>\n<td>-114<\/td>\n<\/tr>\n<tr>\n<td>water<\/td>\n<td>\u00a00<\/td>\n<\/tr>\n<tr>\n<td>pure silver<\/td>\n<td>961<\/td>\n<\/tr>\n<tr>\n<td>pure gold<\/td>\n<td>1063<\/td>\n<\/tr>\n<tr>\n<td>iron<\/td>\n<td>1538<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<div class=\"textbox key-takeaways\">\n<h3>Summary<\/h3>\n<ul id=\"x-ck12-OTdmMTgwNWE5MjU3ZWEyNGVkYjM4MTg0ODhkNTBlYTE.-rsx\">\n<li>The melting point is the temperature at which a solid changes into a liquid.<\/li>\n<li>Intermolecular forces have a strong influence on melting point.<\/li>\n<\/ul>\n<\/div>\n<div class=\"textbox exercises\">\n<h3>Practice<\/h3>\n<p id=\"x-ck12-Y2JlMjQ5M2YzMTNmNmRjMzNmZTI0MTMzYzcwM2IzZmY.-s31\">Use the link below to answer the following questions<\/p>\n<p id=\"x-ck12-ODhjNDZlMzEwNmQ0YTljOGNhOTM1ZGFkYzZiMTFkNDA.-yfr\"><a href=\"http:\/\/chemwiki.ucdavis.edu\/Organic_Chemistry\/Organic_Chemistry_With_a_Biological_Emphasis\/Chapter__2%3a_Introduction_to_organic_structure_and_bonding_II\/Section_2.4%3a_Solubility%2c_melting_points_and_boiling_points\">http:\/\/chemwiki.ucdavis.edu\/Organic_Chemistry\/Organic_Chemistry_With_a_Biological_Emphasis\/Chapter__2%3a_Introduction_to_organic_structure_and_bonding_II\/Section_2.4%3a_Solubility%2c_melting_points_and_boiling_points<\/a><\/p>\n<ol id=\"x-ck12-ODM4NjZkODY1MjA3YzRjZjI2OGRlZWI2ZDM5ZTc3ZmU.-8qn\">\n<li>To what degree of accuracy can melting points be measured?<\/li>\n<li>How can we use melting point data to help identify a compound?<\/li>\n<li>How can we use melting points to assess the purity of a compound?<\/li>\n<\/ol>\n<\/div>\n<div class=\"textbox exercises\">\n<h3>Review<\/h3>\n<ol id=\"x-ck12-OTM0OWE5NTliOTZkMzY5OTgxZDI4ZGY5NzcxNmE1ODA.-sr0\">\n<li>Define melting point.<\/li>\n<li>What happens when a material melts?<\/li>\n<li>Would you expect ethane (C <sub>2 <\/sub>H <sub>6 <\/sub>) to have a higher or lower melting point than water? Explain your answer.<\/li>\n<\/ol>\n<\/div>\n<div class=\"x-ck12-data-problem-set\">\n<div class=\"textbox learning-objectives\">\n<h3>Glossary<\/h3>\n<div class=\"x-ck12-data-vocabulary\">\n<ul id=\"x-ck12-MzY4NmQ3ZjI5ZjU0ZDM1YjM3NmIyZDQ2ODRkOGE0NmM.-vum\">\n<li><strong>incompressible: <\/strong>Unable to be compressed.<\/li>\n<li><strong>melting point: <\/strong>The temperature at which a solid changes into a liquid.<\/li>\n<li><strong>vibrational motion: <\/strong>Back and forth movement.<\/li>\n<\/ul>\n<\/div>\n<\/div>\n<\/div>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q836080\">Show References<\/span><\/p>\n<div id=\"q836080\" class=\"hidden-answer\" style=\"display: none\">\n<h2>References<\/h2>\n<ol>\n<li>Jonas Bergsten (Wikimedia: Bergsten). <a href=\"http:\/\/commons.wikimedia.org\/wiki\/File:Drop_of_water_2003_05.jpg\">http:\/\/commons.wikimedia.org\/wiki\/File:Drop_of_water_2003_05.jpg <\/a>.<\/li>\n<\/ol>\n<\/div>\n<\/div>\n","protected":false},"author":1507,"menu_order":12,"template":"","meta":{"_candela_citation":"[]","CANDELA_OUTCOMES_GUID":"","pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-2602","chapter","type-chapter","status-publish","hentry"],"part":2334,"_links":{"self":[{"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/pressbooks\/v2\/chapters\/2602","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/wp\/v2\/users\/1507"}],"version-history":[{"count":8,"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/pressbooks\/v2\/chapters\/2602\/revisions"}],"predecessor-version":[{"id":3609,"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/pressbooks\/v2\/chapters\/2602\/revisions\/3609"}],"part":[{"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/pressbooks\/v2\/parts\/2334"}],"metadata":[{"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/pressbooks\/v2\/chapters\/2602\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/wp\/v2\/media?parent=2602"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/pressbooks\/v2\/chapter-type?post=2602"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/wp\/v2\/contributor?post=2602"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/wp\/v2\/license?post=2602"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}