{"id":204655,"date":"2025-03-22T12:10:12","date_gmt":"2025-03-22T12:10:12","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=204655"},"modified":"2025-03-22T12:10:14","modified_gmt":"2025-03-22T12:10:14","slug":"a-sample-of-sodium-sulfite-na2so3-has-a-mass-of-2-25-g-2","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/03\/22\/a-sample-of-sodium-sulfite-na2so3-has-a-mass-of-2-25-g-2\/","title":{"rendered":"A sample of sodium sulfite (Na2SO3) has a mass of 2.25 g"},"content":{"rendered":"\n<p>A sample of sodium sulfite (Na2SO3) has a mass of 2.25 g.<br>a. How many Na+ ions are present?<br>b. How many SO3\u00b2? ions are present?<br>c. What is the mass in grams of one formula unit of Na2SO3?<\/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>Let&#8217;s solve each part of the question step by step.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Given:<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Mass of sodium sulfite (Na\u2082SO\u2083) = 2.25 g<\/li>\n<\/ul>\n\n\n\n<p><strong>Step 1: Molar mass of Na\u2082SO\u2083<\/strong><br>First, we need the molar mass of Na\u2082SO\u2083. To calculate this, we add the atomic masses of the elements involved:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Atomic mass of Na = 22.99 g\/mol<\/li>\n\n\n\n<li>Atomic mass of S = 32.07 g\/mol<\/li>\n\n\n\n<li>Atomic mass of O = 16.00 g\/mol<\/li>\n<\/ul>\n\n\n\n<p>The formula for sodium sulfite is Na\u2082SO\u2083, which contains:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>2 Na atoms<\/li>\n\n\n\n<li>1 S atom<\/li>\n\n\n\n<li>3 O atoms<\/li>\n<\/ul>\n\n\n\n<p>So, the molar mass of Na\u2082SO\u2083 is:<\/p>\n\n\n\n<p>[<br>\\text{Molar mass of Na\u2082SO\u2083} = (2 \\times 22.99) + (1 \\times 32.07) + (3 \\times 16.00)<br>]<br>[<br>\\text{Molar mass of Na\u2082SO\u2083} = 45.98 + 32.07 + 48.00 = 126.05 \\, \\text{g\/mol}<br>]<\/p>\n\n\n\n<p><strong>a. How many Na\u207a ions are present?<\/strong><\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>First, we calculate the number of moles of Na\u2082SO\u2083 in the 2.25 g sample.<\/li>\n<\/ol>\n\n\n\n<p>[<br>\\text{Moles of Na\u2082SO\u2083} = \\frac{\\text{mass of Na\u2082SO\u2083}}{\\text{molar mass of Na\u2082SO\u2083}} = \\frac{2.25 \\, \\text{g}}{126.05 \\, \\text{g\/mol}} = 0.0178 \\, \\text{mol}<br>]<\/p>\n\n\n\n<ol start=\"2\" class=\"wp-block-list\">\n<li>From the formula Na\u2082SO\u2083, each formula unit contains 2 Na\u207a ions. Therefore, the number of Na\u207a ions is:<\/li>\n<\/ol>\n\n\n\n<p>[<br>\\text{Number of Na\u207a ions} = 2 \\times \\text{moles of Na\u2082SO\u2083} \\times \\text{Avogadro&#8217;s number}<br>]<br>[<br>\\text{Number of Na\u207a ions} = 2 \\times 0.0178 \\, \\text{mol} \\times 6.022 \\times 10^{23} \\, \\text{ions\/mol}<br>]<br>[<br>\\text{Number of Na\u207a ions} = 2.14 \\times 10^{22} \\, \\text{Na\u207a ions}<br>]<\/p>\n\n\n\n<p><strong>b. How many SO\u2083\u00b2\u207b ions are present?<\/strong><\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>From the formula Na\u2082SO\u2083, each formula unit contains 1 SO\u2083\u00b2\u207b ion. Therefore, the number of SO\u2083\u00b2\u207b ions is the same as the number of Na\u2082SO\u2083 units:<\/li>\n<\/ol>\n\n\n\n<p>[<br>\\text{Number of SO\u2083\u00b2\u207b ions} = \\text{moles of Na\u2082SO\u2083} \\times \\text{Avogadro&#8217;s number}<br>]<br>[<br>\\text{Number of SO\u2083\u00b2\u207b ions} = 0.0178 \\, \\text{mol} \\times 6.022 \\times 10^{23} \\, \\text{ions\/mol}<br>]<br>[<br>\\text{Number of SO\u2083\u00b2\u207b ions} = 1.07 \\times 10^{22} \\, \\text{SO\u2083\u00b2\u207b ions}<br>]<\/p>\n\n\n\n<p><strong>c. What is the mass in grams of one formula unit of Na\u2082SO\u2083?<\/strong><\/p>\n\n\n\n<p>To find the mass of one formula unit of Na\u2082SO\u2083, we need to use the molar mass. The molar mass of Na\u2082SO\u2083 is 126.05 g\/mol, and this corresponds to 1 mole of Na\u2082SO\u2083, which contains Avogadro\u2019s number of formula units.<\/p>\n\n\n\n<p>The mass of one formula unit is:<\/p>\n\n\n\n<p>[<br>\\text{Mass of one formula unit} = \\frac{\\text{Molar mass of Na\u2082SO\u2083}}{\\text{Avogadro&#8217;s number}} = \\frac{126.05 \\, \\text{g\/mol}}{6.022 \\times 10^{23} \\, \\text{formula units\/mol}}<br>]<br>[<br>\\text{Mass of one formula unit} = 2.09 \\times 10^{-22} \\, \\text{g}<br>]<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Summary of answers:<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>a.<\/strong> The number of Na\u207a ions present is ( 2.14 \\times 10^{22} ) ions.<\/li>\n\n\n\n<li><strong>b.<\/strong> The number of SO\u2083\u00b2\u207b ions present is ( 1.07 \\times 10^{22} ) ions.<\/li>\n\n\n\n<li><strong>c.<\/strong> The mass of one formula unit of Na\u2082SO\u2083 is ( 2.09 \\times 10^{-22} \\, \\text{g} ).<\/li>\n<\/ul>\n\n\n\n<p>This problem involved converting the mass of Na\u2082SO\u2083 to moles, then using stoichiometry to find the number of ions, and finally determining the mass of a single formula unit based on the molar mass and Avogadro\u2019s number.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>A sample of sodium sulfite (Na2SO3) has a mass of 2.25 g.a. How many Na+ ions are present?b. How many SO3\u00b2? ions are present?c. What is the mass in grams of one formula unit of Na2SO3? The correct answer and explanation is : Let&#8217;s solve each part of the question step by step. Given: Step [&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-204655","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/204655","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=204655"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/204655\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=204655"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=204655"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=204655"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}