{"id":250536,"date":"2025-07-10T10:23:58","date_gmt":"2025-07-10T10:23:58","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=250536"},"modified":"2025-07-10T10:24:00","modified_gmt":"2025-07-10T10:24:00","slug":"how-many-moles-are-in","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/07\/10\/how-many-moles-are-in\/","title":{"rendered":"How many moles are in"},"content":{"rendered":"\n
Moles I. How many moles are in: a. 25g of NaCl 58.5 b. 125g of HSO c. 100.0g of KMnO d. 74g of KCl e. 35 g of CuSO II. How many grams are in: a. 2.5 moles of NaCl b. 0.50 moles of HSO c. 1.70 moles of KMnO d. 0.25 moles of KCl e. 3.2 moles of CuSO<\/pre>\n\n\n\n
The Correct Answer and Explanation is:<\/mark><\/strong><\/p>\n\n\n\n
I. Finding the number of moles in the given compounds:<\/h3>\n\n\n\n
The formula to calculate the number of moles is:Moles=Mass (g)Molar Mass (g\/mol)\\text{Moles} = \\frac{\\text{Mass (g)}}{\\text{Molar Mass (g\/mol)}}Moles=Molar Mass (g\/mol)Mass (g)\u200b<\/p>\n\n\n\n
We will calculate the molar mass for each compound and then use this formula to find the number of moles.<\/p>\n\n\n\n
a) 25 g of NaCl<\/h4>\n\n\n\n
Molar mass of NaCl = 58.5 g\/molMoles of NaCl=25\u2009g58.5\u2009g\/mol\u22480.427\u2009moles\\text{Moles of NaCl} = \\frac{25 \\, \\text{g}}{58.5 \\, \\text{g\/mol}} \\approx 0.427 \\, \\text{moles}Moles of NaCl=58.5g\/mol25g\u200b\u22480.427moles<\/p>\n\n\n\n
b) 125 g of H\u2082SO\u2084<\/h4>\n\n\n\n
Molar mass of H\u2082SO\u2084 = 2(1.008) + 32.06 + 4(16.00) = 98.08 g\/molMoles of H\u2082SO\u2084=125\u2009g98.08\u2009g\/mol\u22481.275\u2009moles\\text{Moles of H\u2082SO\u2084} = \\frac{125 \\, \\text{g}}{98.08 \\, \\text{g\/mol}} \\approx 1.275 \\, \\text{moles}Moles of H\u2082SO\u2084=98.08g\/mol125g\u200b\u22481.275moles<\/p>\n\n\n\n
c) 100.0 g of KMnO\u2084<\/h4>\n\n\n\n
Molar mass of KMnO\u2084 = 39.10 + 54.94 + 4(16.00) = 158.04 g\/molMoles of KMnO\u2084=100.0\u2009g158.04\u2009g\/mol\u22480.633\u2009moles\\text{Moles of KMnO\u2084} = \\frac{100.0 \\, \\text{g}}{158.04 \\, \\text{g\/mol}} \\approx 0.633 \\, \\text{moles}Moles of KMnO\u2084=158.04g\/mol100.0g\u200b\u22480.633moles<\/p>\n\n\n\n
d) 74 g of KCl<\/h4>\n\n\n\n
Molar mass of KCl = 39.10 + 35.45 = 74.55 g\/molMoles of KCl=74\u2009g74.55\u2009g\/mol\u22480.993\u2009moles\\text{Moles of KCl} = \\frac{74 \\, \\text{g}}{74.55 \\, \\text{g\/mol}} \\approx 0.993 \\, \\text{moles}Moles of KCl=74.55g\/mol74g\u200b\u22480.993moles<\/p>\n\n\n\n
e) 35 g of CuSO\u2084<\/h4>\n\n\n\n
Molar mass of CuSO\u2084 = 63.55 + 32.07 + 4(16.00) = 159.62 g\/molMoles of CuSO\u2084=35\u2009g159.62\u2009g\/mol\u22480.219\u2009moles\\text{Moles of CuSO\u2084} = \\frac{35 \\, \\text{g}}{159.62 \\, \\text{g\/mol}} \\approx 0.219 \\, \\text{moles}Moles of CuSO\u2084=159.62g\/mol35g\u200b\u22480.219moles<\/p>\n\n\n\n
II. Finding the mass in grams for the given moles:<\/h3>\n\n\n\n
The formula to calculate mass is:Mass (g)=Moles\u00d7Molar Mass (g\/mol)\\text{Mass (g)} = \\text{Moles} \\times \\text{Molar Mass (g\/mol)}Mass (g)=Moles\u00d7Molar Mass (g\/mol)<\/p>\n\n\n\n
a) 2.5 moles of NaCl<\/h4>\n\n\n\n
Mass of NaCl=2.5\u2009moles\u00d758.5\u2009g\/mol=146.25\u2009g\\text{Mass of NaCl} = 2.5 \\, \\text{moles} \\times 58.5 \\, \\text{g\/mol} = 146.25 \\, \\text{g}Mass of NaCl=2.5moles\u00d758.5g\/mol=146.25g<\/p>\n\n\n\n
b) 0.50 moles of H\u2082SO\u2084<\/h4>\n\n\n\n
Mass of H\u2082SO\u2084=0.50\u2009moles\u00d798.08\u2009g\/mol=49.04\u2009g\\text{Mass of H\u2082SO\u2084} = 0.50 \\, \\text{moles} \\times 98.08 \\, \\text{g\/mol} = 49.04 \\, \\text{g}Mass of H\u2082SO\u2084=0.50moles\u00d798.08g\/mol=49.04g<\/p>\n\n\n\n
c) 1.70 moles of KMnO\u2084<\/h4>\n\n\n\n
Mass of KMnO\u2084=1.70\u2009moles\u00d7158.04\u2009g\/mol=269.67\u2009g\\text{Mass of KMnO\u2084} = 1.70 \\, \\text{moles} \\times 158.04 \\, \\text{g\/mol} = 269.67 \\, \\text{g}Mass of KMnO\u2084=1.70moles\u00d7158.04g\/mol=269.67g<\/p>\n\n\n\n
d) 0.25 moles of KCl<\/h4>\n\n\n\n
Mass of KCl=0.25\u2009moles\u00d774.55\u2009g\/mol=18.64\u2009g\\text{Mass of KCl} = 0.25 \\, \\text{moles} \\times 74.55 \\, \\text{g\/mol} = 18.64 \\, \\text{g}Mass of KCl=0.25moles\u00d774.55g\/mol=18.64g<\/p>\n\n\n\n
e) 3.2 moles of CuSO\u2084<\/h4>\n\n\n\n
Mass of CuSO\u2084=3.2\u2009moles\u00d7159.62\u2009g\/mol=511.78\u2009g\\text{Mass of CuSO\u2084} = 3.2 \\, \\text{moles} \\times 159.62 \\, \\text{g\/mol} = 511.78 \\, \\text{g}Mass of CuSO\u2084=3.2moles\u00d7159.62g\/mol=511.78g<\/p>\n\n\n\n
Summary:<\/h3>\n\n\n\n
I. Moles:<\/h4>\n\n\n\n
    \n
  • NaCl: 0.427 moles<\/li>\n\n\n\n
  • H\u2082SO\u2084: 1.275 moles<\/li>\n\n\n\n
  • KMnO\u2084: 0.633 moles<\/li>\n\n\n\n
  • KCl: 0.993 moles<\/li>\n\n\n\n
  • CuSO\u2084: 0.219 moles<\/li>\n<\/ul>\n\n\n\n
    II. Mass:<\/h4>\n\n\n\n
      \n
    • NaCl: 146.25 g<\/li>\n\n\n\n
    • H\u2082SO\u2084: 49.04 g<\/li>\n\n\n\n
    • KMnO\u2084: 269.67 g<\/li>\n\n\n\n
    • KCl: 18.64 g<\/li>\n\n\n\n
    • CuSO\u2084: 511.78 g<\/li>\n<\/ul>\n\n\n\n
      By using the molar masses and the moles formula, you can easily calculate moles from mass and mass from moles. Always ensure that you use the correct molar mass for each compound!<\/p>\n\n\n\n
      \"\"<\/figure>\n","protected":false},"excerpt":{"rendered":"
      Moles I. How many moles are in: a. 25g of NaCl 58.5 b. 125g of HSO c. 100.0g of KMnO d. 74g of KCl e. 35 g of CuSO II. How many grams are in: a. 2.5 moles of NaCl b. 0.50 moles of HSO c. 1.70 moles of KMnO d. 0.25 moles of KCl e. 3.2 moles of CuSO […]<\/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-250536","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/250536","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=250536"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/250536\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=250536"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=250536"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=250536"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}