{"id":120,"date":"2009-09-28T22:44:07","date_gmt":"2009-09-29T05:44:07","guid":{"rendered":"http:\/\/wordpress.reed.edu\/chem201202\/2009\/09\/unsaturation-number-textbook-error.html"},"modified":"2014-03-18T10:13:04","modified_gmt":"2014-03-18T17:13:04","slug":"unsaturation-number-textbook-error","status":"publish","type":"post","link":"https:\/\/blogs.reed.edu\/chem201202\/2009\/09\/unsaturation-number-textbook-error\/","title":{"rendered":"Unsaturation Number (textbook error)"},"content":{"rendered":"<p>Chapter 4 introduces so-called &#8220;road map&#8221; problems. Problem 4.51 &amp; 4.52 are typical examples. A &#8220;road map&#8221; problem gives you some information about the composition of a molecule and its chemical behavior (what you can turn it into, how you can make it from other substances). Your job is to figure out the molecule&#8217;s structure.<\/p>\n<p>A key step in the solution of a &#8220;road map&#8221; problem is to calculate the molecule&#8217;s <b>unsaturation number <\/b>(also called &#8220;degree of unsaturation&#8221; and &#8220;number of units of unsaturation&#8221;). Loudon explains how to perform this calculation in section 4.3 and I won&#8217;t cover this material in lecture. I do want to call your attention, however, to an error in the book. The term &#8220;<i><b>2C<\/b><\/i>&#8221; should appear only once in equation 4.7 (compare equations 4.5, 4.6, and 4.7).<\/p>\n<p>FYI &#8211; I learned a slightly different (but mathematically equivalent) equation as a student: <b>U = #C + 1 &#8211; #H\/2 + #N\/2<\/b>.<\/p>\n<p>Whichever equation you learn, notice that:<\/p>\n<ul>\n<li>the number of oxygens does not affect the unsaturation number<\/li>\n<li><b>#H<\/b> represents the number of hydrogens plus the number of halogens.\n<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>Chapter 4 introduces so-called &#8220;road map&#8221; problems. Problem 4.51 &amp; 4.52 are typical examples. A &#8220;road map&#8221; problem gives you some information about the composition of a molecule and its chemical behavior (what you can turn it into, how you&#8230;<\/p>\n","protected":false},"author":55,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-120","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/blogs.reed.edu\/chem201202\/wp-json\/wp\/v2\/posts\/120","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.reed.edu\/chem201202\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.reed.edu\/chem201202\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.reed.edu\/chem201202\/wp-json\/wp\/v2\/users\/55"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.reed.edu\/chem201202\/wp-json\/wp\/v2\/comments?post=120"}],"version-history":[{"count":2,"href":"https:\/\/blogs.reed.edu\/chem201202\/wp-json\/wp\/v2\/posts\/120\/revisions"}],"predecessor-version":[{"id":5175,"href":"https:\/\/blogs.reed.edu\/chem201202\/wp-json\/wp\/v2\/posts\/120\/revisions\/5175"}],"wp:attachment":[{"href":"https:\/\/blogs.reed.edu\/chem201202\/wp-json\/wp\/v2\/media?parent=120"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.reed.edu\/chem201202\/wp-json\/wp\/v2\/categories?post=120"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.reed.edu\/chem201202\/wp-json\/wp\/v2\/tags?post=120"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}