{"id":185523,"date":"2025-01-22T17:22:27","date_gmt":"2025-01-22T17:22:27","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=185523"},"modified":"2025-01-22T17:22:29","modified_gmt":"2025-01-22T17:22:29","slug":"the-extinction-coefficient-for-nadh-is-6220-m-1-cm-1-at-340-nm-2","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/01\/22\/the-extinction-coefficient-for-nadh-is-6220-m-1-cm-1-at-340-nm-2\/","title":{"rendered":"The extinction coefficient for NADH is 6220 M^-1 cm^-1 at 340 nm"},"content":{"rendered":"\n<p>The extinction coefficient for NADH is 6220 M^-1 cm^-1 at 340 nm. Calculate the following.<\/p>\n\n\n\n<p>a. The absorbance of a 2.2 times 10^-5 M sample in a 1-cm cuvette at 340 nm<\/p>\n\n\n\n<p>b. The absorbance of a 2.2 times 10^-5 M sample in a 1-mm cuvette at 340 nm<\/p>\n\n\n\n<p>c. The absorbance of a 1 mM sample in a 1-cm cuvette at 340 nm<\/p>\n\n\n\n<p><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-ast-global-color-6-color\"><strong>The Correct Answer and Explanation is :<\/strong><\/mark><\/p>\n\n\n\n<p>The absorbance of a solution is calculated using <strong>Beer-Lambert Law<\/strong>:<\/p>\n\n\n\n<p>[<br>A = \\varepsilon \\cdot c \\cdot l<br>]<\/p>\n\n\n\n<p>Where:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>( A ) is the absorbance<\/li>\n\n\n\n<li>( \\varepsilon ) is the molar extinction coefficient (given as 6220 M(^{-1}) cm(^{-1}) at 340 nm)<\/li>\n\n\n\n<li>( c ) is the concentration of the solution in moles per liter (M)<\/li>\n\n\n\n<li>( l ) is the path length of the cuvette in centimeters (cm)<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">a. The absorbance of a 2.2 \u00d7 10(^{-5}) M sample in a 1-cm cuvette at 340 nm:<\/h3>\n\n\n\n<p>We can substitute the known values into the Beer-Lambert equation:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>( \\varepsilon = 6220 \\, \\text{M}^{-1} \\, \\text{cm}^{-1} )<\/li>\n\n\n\n<li>( c = 2.2 \\times 10^{-5} \\, \\text{M} )<\/li>\n\n\n\n<li>( l = 1 \\, \\text{cm} )<\/li>\n<\/ul>\n\n\n\n<p>Substitute into the equation:<\/p>\n\n\n\n<p>[<br>A = 6220 \\cdot (2.2 \\times 10^{-5}) \\cdot 1<br>]<\/p>\n\n\n\n<p>[<br>A = 0.137 \\, \\text{(no units)}<br>]<\/p>\n\n\n\n<p>Thus, the absorbance is <strong>0.137<\/strong>.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">b. The absorbance of a 2.2 \u00d7 10(^{-5}) M sample in a 1-mm cuvette at 340 nm:<\/h3>\n\n\n\n<p>For this case, the path length ( l = 1 \\, \\text{mm} = 0.1 \\, \\text{cm} ).<\/p>\n\n\n\n<p>Now, substitute the values into the Beer-Lambert equation:<\/p>\n\n\n\n<p>[<br>A = 6220 \\cdot (2.2 \\times 10^{-5}) \\cdot 0.1<br>]<\/p>\n\n\n\n<p>[<br>A = 0.0137<br>]<\/p>\n\n\n\n<p>Thus, the absorbance is <strong>0.0137<\/strong>.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">c. The absorbance of a 1 mM sample in a 1-cm cuvette at 340 nm:<\/h3>\n\n\n\n<p>Here, the concentration ( c = 1 \\, \\text{mM} = 1 \\times 10^{-3} \\, \\text{M} ), and the path length remains ( l = 1 \\, \\text{cm} ).<\/p>\n\n\n\n<p>Substitute the values:<\/p>\n\n\n\n<p>[<br>A = 6220 \\cdot (1 \\times 10^{-3}) \\cdot 1<br>]<\/p>\n\n\n\n<p>[<br>A = 6.22<br>]<\/p>\n\n\n\n<p>Thus, the absorbance is <strong>6.22<\/strong>.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Explanation:<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>In all calculations, the relationship between absorbance, concentration, path length, and the extinction coefficient is fundamental. A higher concentration and a longer path length result in a higher absorbance.<\/li>\n\n\n\n<li>The extinction coefficient (( \\varepsilon )) is a constant for a given substance at a specific wavelength, indicating how strongly the substance absorbs light at that wavelength.<\/li>\n\n\n\n<li>The path length (( l )) is the distance that light travels through the sample, and typically the longer the path length, the more light will be absorbed.<\/li>\n\n\n\n<li>The molar concentration (( c )) directly affects absorbance; higher concentration increases absorbance.<\/li>\n<\/ul>\n\n\n\n<p>In practice, these calculations help in determining concentrations of substances based on the amount of light absorbed at a specific wavelength.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>The extinction coefficient for NADH is 6220 M^-1 cm^-1 at 340 nm. Calculate the following. a. The absorbance of a 2.2 times 10^-5 M sample in a 1-cm cuvette at 340 nm b. The absorbance of a 2.2 times 10^-5 M sample in a 1-mm cuvette at 340 nm c. The absorbance of a 1 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[25],"tags":[],"class_list":["post-185523","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/185523","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/comments?post=185523"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/185523\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=185523"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=185523"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=185523"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}