{"id":219255,"date":"2025-05-25T21:31:29","date_gmt":"2025-05-25T21:31:29","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=219255"},"modified":"2025-05-25T21:31:32","modified_gmt":"2025-05-25T21:31:32","slug":"rank-these-systems-in-order-of-decreasing-entropy","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/05\/25\/rank-these-systems-in-order-of-decreasing-entropy\/","title":{"rendered":"Rank these systems in order of decreasing entropy."},"content":{"rendered":"\n

Rank these systems in order of decreasing entropy. Rank from highest to lowest entropy. To rank items as equivalent overlap them.<\/p>\n\n\n\n

1 mol of hydrogen peroxide gas at 273K and 40L
\u00bd mol of helium gas at 100 K and 20 L
1 mol of chlorine gas at 273K and 40 L
\u00bd mol of helium gas at 273K and 20 L
1 mol of helium gas at 273K and 20 L
\u00bd mol of liquid helium at 100K<\/p>\n\n\n\n

The Correct Answer and Explanation is:<\/mark><\/strong><\/p>\n\n\n\n

Answers:<\/strong><\/h3>\n\n\n\n

10.<\/strong> The correct answer is d. Na(s)<\/strong>
11.<\/strong> The correct answer is d. 2 mol of HCN<\/strong>
12.<\/strong><\/p>\n\n\n\n

    \n
  • a. Positive (\u0394S > 0)<\/strong><\/li>\n\n\n\n
  • b. Positive (\u0394S > 0)<\/strong><\/li>\n\n\n\n
  • c. Negative (\u0394S < 0)<\/strong><\/li>\n\n\n\n
  • d. Positive (\u0394S > 0)<\/strong><\/li>\n<\/ul>\n\n\n\n
    \n\n\n\n

    Explanation <\/strong><\/h3>\n\n\n\n

    Question 10:<\/strong>
    Standard molar entropy (S\u00ba) refers to the entropy content of one mole of a substance at standard conditions (298 K and 1 atm). Entropy generally increases from solids to liquids to gases. Among the options:<\/p>\n\n\n\n

      \n
    • CH\u2084(g)<\/strong>, He(g)<\/strong>: gases \u2192 high entropy<\/li>\n\n\n\n
    • CH\u2083CH\u2082OH(l)<\/strong>: liquid \u2192 moderate entropy<\/li>\n\n\n\n
    • H\u2082O(s)<\/strong>: solid \u2192 low entropy<\/li>\n\n\n\n
    • Na(s)<\/strong>: solid metal \u2192 lowest entropy<\/strong>, since metals are highly ordered in crystal form<\/li>\n<\/ul>\n\n\n\n

      Thus, Na(s)<\/strong> has the lowest<\/strong> standard molar entropy.<\/p>\n\n\n\n

      Question 11:<\/strong>
      Entropy depends on amount (moles)<\/strong>, not mass alone. While all options refer to HCN, they differ in quantity:<\/p>\n\n\n\n

        \n
      • 0.5 g<\/strong> and 2 kg<\/strong> of HCN are masses, but entropy is extensive\u2014it increases with the number of particles.<\/li>\n\n\n\n
      • 1 mol<\/strong> vs. 2 mol<\/strong>: more moles = more microstates = higher entropy.<\/li>\n<\/ul>\n\n\n\n

        So, 2 mol of HCN (d)<\/strong> has the highest entropy<\/strong>.<\/p>\n\n\n\n

        Question 12:<\/strong>
        Entropy change (\u0394S) depends on the change in disorder<\/strong> during a reaction:<\/p>\n\n\n\n

          \n
        • a. CaCO\u2083(s) \u2192 CaO(s) + CO\u2082(g):<\/strong> A gas forms from solids \u2192 \u0394S > 0 (positive)<\/strong><\/li>\n\n\n\n
        • b. CS\u2082(l) \u2192 CS\u2082(g):<\/strong> Liquid to gas = more disorder \u2192 \u0394S > 0 (positive)<\/strong><\/li>\n\n\n\n
        • c. 2 Hg(l) + O\u2082(g) \u2192 2 HgO(s):<\/strong> Liquids and gas forming solid = decrease in entropy \u2192 \u0394S < 0 (negative)<\/strong><\/li>\n\n\n\n
        • d. 2 Na\u2082O\u2082(s) + 2 H\u2082O(l) \u2192 4 NaOH(aq) + O\u2082(g):<\/strong> More particles, especially gas and aqueous ions formed = more disorder \u2192 \u0394S > 0 (positive)<\/strong><\/li>\n<\/ul>\n\n\n\n

          In summary, entropy is influenced by phase, number of particles, and state changes<\/strong>. Gases and more moles usually mean higher entropy<\/strong>.<\/p>\n\n\n\n

          \"\"<\/figure>\n","protected":false},"excerpt":{"rendered":"

          Rank these systems in order of decreasing entropy. Rank from highest to lowest entropy. To rank items as equivalent overlap them. 1 mol of hydrogen peroxide gas at 273K and 40L\u00bd mol of helium gas at 100 K and 20 L1 mol of chlorine gas at 273K and 40 L\u00bd mol of helium gas at […]<\/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-219255","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/219255","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=219255"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/219255\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=219255"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=219255"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=219255"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}