{"id":96,"date":"2024-10-24T20:59:37","date_gmt":"2024-10-25T00:59:37","guid":{"rendered":"https:\/\/sites.temple.edu\/chemdemo\/?p=96"},"modified":"2024-10-25T16:22:01","modified_gmt":"2024-10-25T20:22:01","slug":"human-salt-bridge","status":"publish","type":"post","link":"https:\/\/sites.temple.edu\/chemdemo\/2024\/10\/24\/human-salt-bridge\/","title":{"rendered":"Human Salt-Bridge"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\">Purpose<\/h2>\n\n\n\n<p>To help students understand the principles of a galvanic cell and the importance of a salt bridge in maintaining electrical conductivity.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Materials Needed<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Voltmeter<\/li>\n\n\n\n<li>Beakers of 1 M zinc sulfate<\/li>\n\n\n\n<li>Beakers of copper (II) sulfate<\/li>\n\n\n\n<li>Copper strip<\/li>\n\n\n\n<li>Zinc strip<\/li>\n\n\n\n<li>Paper towel<\/li>\n\n\n\n<li>Safety equipment (as needed)<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Procedure<\/h2>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Setup<\/strong>: Introduce the voltmeter, zinc sulfate solution, copper sulfate solution, and metal strips.<\/li>\n\n\n\n<li><strong>Student Engagement<\/strong>: Ask students how to arrange the metal strips in the solutions to produce a positive voltage reading on the voltmeter.<\/li>\n\n\n\n<li><strong>Assembly<\/strong>:<\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Allow students to suggest placing the strips in opposing solutions. Follow their suggestions and observe the results.<\/li>\n\n\n\n<li>Note the brief voltage reading and explain why it drops quickly.<\/li>\n\n\n\n<li>Demonstrate copper plating onto zinc and explain the concept of short-circuiting.<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Electrolyte Explanation<\/strong>:<\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>When students suggest placing each metal in its respective solution without a salt bridge, discuss the missing component.<\/li>\n\n\n\n<li>Use your fingers as a salt bridge to illustrate electron flow and charge balance.<\/li>\n\n\n\n<li>Mention the safety of the demonstration based on the MSDS and emphasize handwashing afterward.<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Alternative Salt Bridge<\/strong>: Show the use of a paper towel soaked in zinc sulfate as a salt bridge.<\/li>\n<\/ol>\n\n\n\n<h2 class=\"wp-block-heading\">Chemical Equations<\/h2>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th><strong>Half-Reaction<\/strong><\/th><th><strong>Equation<\/strong><\/th><th><strong>Standard Reduction Potential (E\u00b0)<\/strong><\/th><\/tr><\/thead><tbody><tr><td>Copper Reduction<\/td><td>Cu\u00b2\u207a(aq) + 2e\u207b \u2192 Cu(s)<\/td><td>E\u00b0 = +0.34 V<\/td><\/tr><tr><td>Zinc Oxidation<\/td><td>Zn(s) \u2192 Zn\u00b2\u207a(aq) + 2e\u207b<\/td><td>E\u00b0 = -0.76 V<\/td><\/tr><tr><td>Overall Cell Reaction<\/td><td>Cu(s) + Zn\u00b2\u207a(aq) \u2192 Zn(s) + Cu\u00b2\u207a(aq)<\/td><td>E\u00b0cell = -1.1 V<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">Conclusion<\/h2>\n\n\n\n<p>This demonstration illustrates the crucial role of the salt bridge in maintaining the flow of ions and electrons in a galvanic cell, highlighting the principles of electrochemistry.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Purpose To help students understand the principles of a galvanic cell and the importance of a salt bridge in maintaining electrical conductivity. Materials Needed Procedure&#8230;<\/p>\n<div class=\"more-link-wrapper\"><a class=\"more-link\" href=\"https:\/\/sites.temple.edu\/chemdemo\/2024\/10\/24\/human-salt-bridge\/\">Continue Reading<span class=\"screen-reader-text\">Human Salt-Bridge<\/span><\/a><\/div>\n","protected":false},"author":36673,"featured_media":0,"comment_status":"open","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[],"class_list":["post-96","post","type-post","status-publish","format-standard","hentry","category-demonstrations","entry"],"_links":{"self":[{"href":"https:\/\/sites.temple.edu\/chemdemo\/wp-json\/wp\/v2\/posts\/96","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/sites.temple.edu\/chemdemo\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/sites.temple.edu\/chemdemo\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/sites.temple.edu\/chemdemo\/wp-json\/wp\/v2\/users\/36673"}],"replies":[{"embeddable":true,"href":"https:\/\/sites.temple.edu\/chemdemo\/wp-json\/wp\/v2\/comments?post=96"}],"version-history":[{"count":1,"href":"https:\/\/sites.temple.edu\/chemdemo\/wp-json\/wp\/v2\/posts\/96\/revisions"}],"predecessor-version":[{"id":97,"href":"https:\/\/sites.temple.edu\/chemdemo\/wp-json\/wp\/v2\/posts\/96\/revisions\/97"}],"wp:attachment":[{"href":"https:\/\/sites.temple.edu\/chemdemo\/wp-json\/wp\/v2\/media?parent=96"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/sites.temple.edu\/chemdemo\/wp-json\/wp\/v2\/categories?post=96"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/sites.temple.edu\/chemdemo\/wp-json\/wp\/v2\/tags?post=96"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}