{"id":264989,"date":"2025-07-21T17:37:53","date_gmt":"2025-07-21T17:37:53","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=264989"},"modified":"2025-07-21T17:37:55","modified_gmt":"2025-07-21T17:37:55","slug":"choose-the-substance-with-the-highest-viscosity-5","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/07\/21\/choose-the-substance-with-the-highest-viscosity-5\/","title":{"rendered":"Choose the substance with the highest viscosity"},"content":{"rendered":"\n
    \n
  1. Choose the substance with the highest viscosity: A) water at 10\u00c2\u00b0C B) water at 20\u00c2\u00b0C C) water at 30\u00c2\u00b0C D) water at 40\u00c2\u00b0C E) water at 50\u00c2\u00b0C 13. What is the strongest type of intermolecular force present between NaCl and CHF2? A) dispersion B) dipole-dipole C) hydrogen bonding D) ion-dipole E) none of the above 14. Which of the following statements is TRUE? A) At a given temperature, lighter gas particles travel more slowly than heavier gas particles. B) The smaller the gas particle, the slower it will effuse. C) The higher the temperature, the lower the average kinetic energy of the sample. D) At low temperatures, intermolecular forces become important and the pressure of a gas will be lower than predicted by the ideal gas law. E) None of the above statements are true. 15. Some things take longer to cook at high altitudes than at low altitudes because: A) water boils at a lower temperature at high altitude than at low altitude. B) water boils at a higher temperature at high altitude than at low altitude. C) heat isn’t conducted as well in low density air. D) natural gas flames don’t burn as hot at high altitudes. E) there is higher moisture content in the air at high altitude. Part II: Short Answers and Calculations. 16. Vessel A contains CO2 at 0\u00c2\u00b0C and 1 atm. Vessel B contains SO2 at 20\u00c2\u00b0C and 0.5 atm. The two vessels are the same size. Which vessel contains more molecules? Which contains more mass? In which vessel is the average kinetic energy of molecules higher?<\/li>\n<\/ol>\n\n\n\n

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

    2. Choose the substance with the highest viscosity:<\/strong><\/p>\n\n\n\n

    The viscosity of water generally decreases as temperature increases, because higher temperatures cause molecules to move faster, which decreases the internal friction. Therefore, water at 10\u00b0C<\/strong> will have the highest viscosity compared to the other temperatures (20\u00b0C, 30\u00b0C, 40\u00b0C, 50\u00b0C). This is because at lower temperatures, water molecules are moving more slowly, increasing the interactions between them and hence the viscosity.<\/p>\n\n\n\n

    \n\n\n\n

    13. What is the strongest type of intermolecular force present between NaCl and CHF2?<\/strong><\/p>\n\n\n\n

    NaCl is an ionic compound, and CHF2 is a polar molecule. The strongest intermolecular force present between these two would be ion-dipole interactions<\/strong> (option D). In this case, the positive ions from NaCl (Na\u207a) interact with the dipole of CHF2 (since CHF2 has a partial positive charge on the hydrogen atoms and a partial negative charge on the fluorine atom). Ion-dipole interactions are typically stronger than dipole-dipole or hydrogen bonding in this case.<\/p>\n\n\n\n

    \n\n\n\n

    14. Which of the following statements is TRUE?<\/strong><\/p>\n\n\n\n

    Let’s evaluate each option:<\/p>\n\n\n\n

      \n
    • A) At a given temperature, lighter gas particles travel more slowly than heavier gas particles.<\/strong>
      This is incorrect. According to the Kinetic Molecular Theory<\/strong>, at the same temperature, lighter molecules have higher average velocities compared to heavier molecules.<\/li>\n\n\n\n
    • B) The smaller the gas particle, the slower it will effuse.<\/strong>
      This is also incorrect. Smaller gas particles effuse faster than larger ones, according to Graham’s law of effusion.<\/li>\n\n\n\n
    • C) The higher the temperature, the lower the average kinetic energy of the sample.<\/strong>
      This is false. The average kinetic energy of gas molecules increases<\/strong> with temperature (it is proportional to temperature).<\/li>\n\n\n\n
    • D) At low temperatures, intermolecular forces become important and the pressure of a gas will be lower than predicted by the ideal gas law.<\/strong>
      This is TRUE<\/strong>. At low temperatures, gas molecules move more slowly, and intermolecular forces become more significant. The ideal gas law assumes no intermolecular forces, so at low temperatures and high pressures, real gases deviate from ideal behavior, and the pressure is often lower than predicted by the ideal gas law.<\/li>\n\n\n\n
    • E) None of the above statements are true.<\/strong>
      This is false because D is true.<\/li>\n<\/ul>\n\n\n\n

      Correct answer: D<\/strong><\/p>\n\n\n\n

      \n\n\n\n

      15. Some things take longer to cook at high altitudes than at low altitudes because:<\/strong><\/p>\n\n\n\n

      The correct explanation is A) water boils at a lower temperature at high altitude than at low altitude<\/strong>. At higher altitudes, the atmospheric pressure is lower, so the boiling point of water decreases. This means that water boils at a lower temperature, which is less efficient for cooking food, making it take longer to cook at higher altitudes.<\/p>\n\n\n\n

      \n\n\n\n

      16. Vessel A contains CO2 at 0\u00b0C and 1 atm. Vessel B contains SO2 at 20\u00b0C and 0.5 atm. The two vessels are the same size. Which vessel contains more molecules? Which contains more mass? In which vessel is the average kinetic energy of molecules higher?<\/strong><\/p>\n\n\n\n

        \n
      • Which vessel contains more molecules?<\/strong>
        Use the ideal gas law to determine the number of moles: PV=nRTPV = nRTPV=nRT. Since the volumes, pressures, and temperatures are different, the number of molecules will be based on the pressures and temperatures. For Vessel A<\/strong>:
        nA=PAVRTA=1atm\u00d7VR\u00d70\u00b0Cn_A = \\frac{P_A V}{RT_A} = \\frac{1 atm \\times V}{R \\times 0\u00b0C}nA\u200b=RTA\u200bPA\u200bV\u200b=R\u00d70\u00b0C1atm\u00d7V\u200b For Vessel B<\/strong>:
        nB=PBVRTB=0.5atm\u00d7VR\u00d720\u00b0Cn_B = \\frac{P_B V}{RT_B} = \\frac{0.5 atm \\times V}{R \\times 20\u00b0C}nB\u200b=RTB\u200bPB\u200bV\u200b=R\u00d720\u00b0C0.5atm\u00d7V\u200b Since the pressure and temperature for Vessel B are lower than for Vessel A, Vessel A will contain more molecules<\/strong>.<\/li>\n\n\n\n
      • Which vessel contains more mass?<\/strong>
        The number of moles (from above) is important, but also the molar masses of the gases need to be considered. CO2 (44 g\/mol) has a lower molar mass than SO2 (64 g\/mol). Although Vessel A contains more molecules, Vessel B will contain more mass<\/strong> because SO2 has a greater molar mass.<\/li>\n\n\n\n
      • In which vessel is the average kinetic energy of molecules higher?<\/strong>
        The average kinetic energy of gas molecules is directly related to the temperature: KEavg=32kTKE_{\\text{avg}} = \\frac{3}{2} k TKEavg\u200b=23\u200bkT. Since the temperature of Vessel B (20\u00b0C) is higher than that of Vessel A (0\u00b0C), Vessel B will have higher average kinetic energy<\/strong>.<\/li>\n<\/ul>\n\n\n\n
        \"\"<\/figure>\n","protected":false},"excerpt":{"rendered":"

        The Correct Answer and Explanation is: 2. Choose the substance with the highest viscosity: The viscosity of water generally decreases as temperature increases, because higher temperatures cause molecules to move faster, which decreases the internal friction. Therefore, water at 10\u00b0C will have the highest viscosity compared to the other temperatures (20\u00b0C, 30\u00b0C, 40\u00b0C, 50\u00b0C). This […]<\/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-264989","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/264989","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=264989"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/264989\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=264989"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=264989"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=264989"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}