{"id":241953,"date":"2025-07-04T04:40:13","date_gmt":"2025-07-04T04:40:13","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=241953"},"modified":"2025-07-04T04:40:15","modified_gmt":"2025-07-04T04:40:15","slug":"one-drop-of-water-from-a-medicine-dropper-has-a-volume-of-approximately-0-050-ml","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/07\/04\/one-drop-of-water-from-a-medicine-dropper-has-a-volume-of-approximately-0-050-ml\/","title":{"rendered":"One drop of water from a medicine dropper has a volume of approximately 0.050 mL"},"content":{"rendered":"\n

One drop of water from a medicine dropper has a volume of approximately 0.050 mL (1 mL = 1 cm3) a.) Determine the number of water molecules in a drop of water. (The density of water is 1.0 g\/cm3). b.) How many H atoms would be present in these molecules?<\/p>\n\n\n\n

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

To determine the number of water molecules and the number of hydrogen atoms in a drop of water, let’s break this down step by step.<\/p>\n\n\n\n

a) Determining the number of water molecules in a drop of water:<\/h3>\n\n\n\n
    \n
  1. Volume of the drop<\/strong>: We are given that the volume of a drop of water is 0.050 mL. Since 1 mL = 1 cm\u00b3, the volume of the drop is also 0.050 cm\u00b3.<\/li>\n\n\n\n
  2. Mass of the water in the drop<\/strong>: The density of water is given as 1.0 g\/cm\u00b3. So, the mass of the water in the drop is: Mass=Density\u00d7Volume\\text{Mass} = \\text{Density} \\times \\text{Volume}Mass=Density\u00d7Volume Mass=1.0\u2009g\/cm3\u00d70.050\u2009cm3=0.050\u2009g\\text{Mass} = 1.0 \\, \\text{g\/cm}^3 \\times 0.050 \\, \\text{cm}^3 = 0.050 \\, \\text{g}Mass=1.0g\/cm3\u00d70.050cm3=0.050g<\/li>\n\n\n\n
  3. Moles of water<\/strong>: The molar mass of water (H\u2082O) is approximately 18.015 g\/mol. To find the number of moles in the drop, we use the formula: Moles\u00a0of\u00a0H\u2082O=MassMolar\u00a0mass\\text{Moles of H\u2082O} = \\frac{\\text{Mass}}{\\text{Molar mass}}Moles\u00a0of\u00a0H\u2082O=Molar\u00a0massMass\u200b Moles\u00a0of\u00a0H\u2082O=0.050\u2009g18.015\u2009g\/mol\u22480.00277\u2009mol\\text{Moles of H\u2082O} = \\frac{0.050 \\, \\text{g}}{18.015 \\, \\text{g\/mol}} \\approx 0.00277 \\, \\text{mol}Moles\u00a0of\u00a0H\u2082O=18.015g\/mol0.050g\u200b\u22480.00277mol<\/li>\n\n\n\n
  4. Number of water molecules<\/strong>: To find the number of water molecules, we use Avogadro\u2019s number, which is 6.022\u00d710236.022 \\times 10^{23}6.022\u00d71023 molecules per mole: Number\u00a0of\u00a0molecules=Moles\u00a0of\u00a0H\u2082O\u00d7Avogadro\u2019s\u00a0number\\text{Number of molecules} = \\text{Moles of H\u2082O} \\times \\text{Avogadro’s number}Number\u00a0of\u00a0molecules=Moles\u00a0of\u00a0H\u2082O\u00d7Avogadro\u2019s\u00a0number Number\u00a0of\u00a0molecules=0.00277\u2009mol\u00d76.022\u00d71023\u2009molecules\/mol\\text{Number of molecules} = 0.00277 \\, \\text{mol} \\times 6.022 \\times 10^{23} \\, \\text{molecules\/mol}Number\u00a0of\u00a0molecules=0.00277mol\u00d76.022\u00d71023molecules\/mol Number\u00a0of\u00a0molecules\u22481.67\u00d71021\u2009molecules\\text{Number of molecules} \\approx 1.67 \\times 10^{21} \\, \\text{molecules}Number\u00a0of\u00a0molecules\u22481.67\u00d71021molecules<\/li>\n<\/ol>\n\n\n\n

    b) Determining the number of H atoms:<\/h3>\n\n\n\n
      \n
    1. Each water molecule (H\u2082O) contains 2 hydrogen atoms.<\/li>\n\n\n\n
    2. The total number of hydrogen atoms is: Number\u00a0of\u00a0H\u00a0atoms=2\u00d7Number\u00a0of\u00a0water\u00a0molecules\\text{Number of H atoms} = 2 \\times \\text{Number of water molecules}Number\u00a0of\u00a0H\u00a0atoms=2\u00d7Number\u00a0of\u00a0water\u00a0molecules Number\u00a0of\u00a0H\u00a0atoms=2\u00d71.67\u00d71021=3.34\u00d71021\u2009H\u00a0atoms\\text{Number of H atoms} = 2 \\times 1.67 \\times 10^{21} = 3.34 \\times 10^{21} \\, \\text{H atoms}Number\u00a0of\u00a0H\u00a0atoms=2\u00d71.67\u00d71021=3.34\u00d71021H\u00a0atoms<\/li>\n<\/ol>\n\n\n\n

      Final Answers:<\/h3>\n\n\n\n
        \n
      • a) The number of water molecules in a drop of water is approximately 1.67\u00d710211.67 \\times 10^{21}1.67\u00d71021.<\/li>\n\n\n\n
      • b) The number of hydrogen atoms present in these molecules is approximately 3.34\u00d710213.34 \\times 10^{21}3.34\u00d71021.<\/li>\n<\/ul>\n\n\n\n

        This calculation assumes that the drop is pure water and that all water molecules in the drop are identical.<\/p>\n\n\n\n

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

        One drop of water from a medicine dropper has a volume of approximately 0.050 mL (1 mL = 1 cm3) a.) Determine the number of water molecules in a drop of water. (The density of water is 1.0 g\/cm3). b.) How many H atoms would be present in these molecules? The Correct Answer and Explanation […]<\/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-241953","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/241953","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=241953"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/241953\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=241953"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=241953"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=241953"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}