<?xml version='1.0' encoding='utf-8'?>
<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:contributor>Richard A. Robie</dc:contributor>
  <dc:creator>Bruce S. Hemingway</dc:creator>
  <dc:date>1973</dc:date>
  <dc:description>&lt;p&gt;The enthalpies of formation, &lt;i&gt;&amp;Delta;H&amp;deg;&lt;sub&gt;f&lt;/sub&gt;&lt;/i&gt;&lt;sub&gt;,&lt;/sub&gt; of nesquehonite, MgCO&lt;sub&gt;3&lt;/sub&gt;&amp;nbsp;* 3H&lt;sub&gt;2&lt;/sub&gt;O, and hydromagnesite, 5MgO * 4CO&lt;sub&gt;2&amp;nbsp;&lt;/sub&gt;* 5H&lt;sub&gt;2&lt;/sub&gt;O, have been determined by HCl solution calorimetry. For the reaction MgO(c) + CO&lt;sub&gt;2&lt;/sub&gt;(g) + 3H&lt;sub&gt;2&lt;/sub&gt;O(l) = MgCO&lt;sub&gt;2&lt;/sub&gt; * 3H&lt;sub&gt;2&lt;/sub&gt;O(c), the enthalpy change at 298.15 K is -29,781*40 cal mor' . For the reaction 5MgO(c) + 4CO&lt;sub&gt;2&lt;/sub&gt; + 5H&lt;sub&gt;2&lt;/sub&gt;O = 5MgO *&amp;nbsp;4CO&lt;sub&gt;2&lt;/sub&gt;&amp;nbsp;*&amp;nbsp;5H&lt;sub&gt;2&lt;/sub&gt;O, the enthalpy change at 298.15 K is -120,310&amp;plusmn;120 cal. For MgCO&lt;sub&gt;3&lt;/sub&gt;&amp;nbsp;* 3H&lt;sub&gt;2&lt;/sub&gt;O&amp;nbsp;the standard molar enthalpy and standard Gibbs free energy of formation, &lt;i&gt;&amp;Delta;H&amp;deg;&lt;sub&gt;f,298&lt;/sub&gt;&lt;/i&gt; and &lt;i&gt;&amp;Delta;G&amp;deg;&lt;sub&gt;f,298&lt;/sub&gt;&lt;/i&gt;&amp;nbsp;are -472,576+110 and 412,040&amp;plusmn;120 cal. &lt;i&gt;&amp;Delta;H&amp;deg;&lt;/i&gt;&lt;sub&gt;&lt;i&gt;f,298&lt;/i&gt;&amp;nbsp;&lt;/sub&gt;and&lt;sub&gt;&amp;nbsp;&lt;/sub&gt;&lt;i&gt;&amp;Delta;G&amp;deg;&lt;sub&gt;f,298&lt;/sub&gt;&lt;/i&gt;&lt;sub&gt;&amp;nbsp;&lt;/sub&gt;for 5MgO * 4CO&lt;sub&gt;2&lt;/sub&gt;&amp;nbsp;* 5H&lt;sub&gt;2&lt;/sub&gt;O are -1,557,090&amp;plusmn;250 and -1,401,71 0&amp;plusmn;250 cal.&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:language>en</dc:language>
  <dc:publisher>U.S. Geological Survey</dc:publisher>
  <dc:title>The enthalpies of formation of nesquehonite, MgCO3 * 3H2O, and hydromagnesite, 5MgO * 4CO2 * 5H2O</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>