{"id":115,"date":"2024-10-24T21:27:35","date_gmt":"2024-10-25T01:27:35","guid":{"rendered":"https:\/\/sites.temple.edu\/chemdemo\/?p=115"},"modified":"2024-10-25T16:22:01","modified_gmt":"2024-10-25T20:22:01","slug":"traffic-light-reaction","status":"publish","type":"post","link":"https:\/\/sites.temple.edu\/chemdemo\/2024\/10\/24\/traffic-light-reaction\/","title":{"rendered":"Traffic Light Reaction"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\">Source<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Chemical Demonstrations: A Sourcebook for Teachers, Summerlin and Ealy, page 111<\/li>\n\n\n\n<li>Chemical Demonstrations: A Handbook for Teachers of Chemistry, Shakhashiri, Volume 2, page 142<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Scaling Up<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Scale the procedure from 250 mL to 2 L for a lecture demonstration.<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Chemicals<\/h2>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>Chemical<\/th><th>Amount<\/th><\/tr><\/thead><tbody><tr><td>Glucose<\/td><td>3.0 g<\/td><\/tr><tr><td>Sodium Hydroxide (NaOH)<\/td><td>5.0 g<\/td><\/tr><tr><td>Indigo Carmine<\/td><td>2.0 g<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">Solutions Preparation<\/h2>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Glucose\/NaOH Solution:<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Combine 3.0 g glucose and 5.0 g NaOH in 0.250 L of water. Mix well.<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Indigo Carmine Solution:<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>In a separate container, add 2.0 g of indigo carmine to 200 mL of water. Mix thoroughly.<\/li>\n\n\n\n<li><strong>Note:<\/strong> Make this solution fresh!<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Procedure<\/h2>\n\n\n\n<p><strong>Initial Setup:<\/strong><\/p>\n\n\n\n<ol class=\"wp-block-list\"><\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Place 50 mL of the glucose\/NaOH solution in a 250 mL flask.<\/li>\n\n\n\n<li>Add 5-10 mL of the indigo carmine indicator solution. The solution should start out as light yellow (the indicator is reduced by alkaline dextrose, producing yellow).<\/li>\n<\/ul>\n\n\n\n<p><strong>Stopper and Swirl:<\/strong><\/p>\n\n\n\n<ol class=\"wp-block-list\"><\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Stopper the flask and gently swirl it.<\/li>\n\n\n\n<li>The solution should turn red as swirling introduces oxygen, which oxidizes the indicator and produces the red color.<\/li>\n\n\n\n<li>If the red color does not persist, add more indicator.<\/li>\n<\/ul>\n\n\n\n<p><strong>Shaking the Flask:<\/strong><\/p>\n\n\n\n<ol class=\"wp-block-list\"><\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Shake the flask. This introduces more oxygen and causes further oxidation of the indicator, resulting in a green color.<\/li>\n<\/ul>\n\n\n\n<p><strong>Observation:<\/strong><\/p>\n\n\n\n<ol class=\"wp-block-list\"><\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Allow the solution to stand. The dextrose will reduce the indicator back to the yellow color.<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Safety Precautions<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Wear appropriate personal protective equipment (PPE) including gloves and goggles.<\/li>\n\n\n\n<li>Handle sodium hydroxide with care, as it is caustic.<\/li>\n<\/ul>\n\n\n\n<p>This demonstration effectively illustrates the principles of oxidation and reduction through a visually engaging traffic light reaction.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Source Scaling Up Chemicals Chemical Amount Glucose 3.0 g Sodium Hydroxide (NaOH) 5.0 g Indigo Carmine 2.0 g Solutions Preparation Procedure Initial Setup: Stopper and&#8230;<\/p>\n<div class=\"more-link-wrapper\"><a class=\"more-link\" href=\"https:\/\/sites.temple.edu\/chemdemo\/2024\/10\/24\/traffic-light-reaction\/\">Continue Reading<span class=\"screen-reader-text\">Traffic Light Reaction<\/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-115","post","type-post","status-publish","format-standard","hentry","category-demonstrations","entry"],"_links":{"self":[{"href":"https:\/\/sites.temple.edu\/chemdemo\/wp-json\/wp\/v2\/posts\/115","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=115"}],"version-history":[{"count":1,"href":"https:\/\/sites.temple.edu\/chemdemo\/wp-json\/wp\/v2\/posts\/115\/revisions"}],"predecessor-version":[{"id":116,"href":"https:\/\/sites.temple.edu\/chemdemo\/wp-json\/wp\/v2\/posts\/115\/revisions\/116"}],"wp:attachment":[{"href":"https:\/\/sites.temple.edu\/chemdemo\/wp-json\/wp\/v2\/media?parent=115"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/sites.temple.edu\/chemdemo\/wp-json\/wp\/v2\/categories?post=115"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/sites.temple.edu\/chemdemo\/wp-json\/wp\/v2\/tags?post=115"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}