A solid sample containing some Fe2+ ion weighs 1.026 g. It requires 26.54 mL of 0.01486 M KMnO4 to titrate the Fe2+ in the dissolved sample to the pink endpoint. How many moles of MnO4 are required? 9.860 x 10-5 moles 0.01486 moles 1.635 x 10-6 moles 3.944 x 10-1 moles 3.944 x 10-4 moles QUESTION 7 Questions 6 through 9 refer to the following situation: A solid sample containing some Fe2+ ion weighs 1.026 g. It requires 26.54 mL of 0.01486 M KMnO4 to titrate the Fe2+ in the dissolved sample to the pink endpoint. How many moles of Fe2+ are present in this sample? [Hint: Use your answer to Question 61] 1.972 x 10-3 moles 4.935 x 10-4 moles 944 x 10-3 moles 1.972 moles 0.0817 moles QUESTION 8 Questions 6 through 9 refer to the following situation: A solid sample containing some Fe2+ ion weighs 1.026 g. It requires 26.54 mL of 0.01486 M KMnO4 to titrate the Fe2+ in the dissolved sample to the pink endpoint. How many grams of iron are present in the sample? Enter the number of grams in the space provided. Do not write any units! [Hint: Use your answer to Question 7! The molar mass of Fe is 55.845 g\/mol] QUESTION 9 Questions 6 through 9 refer to the following situation: A solid sample containing some Fe2+ ion weighs 1.026 g. It requires 26.54 mL of 0.01486 M KMnO4 to titrate the Fe2+ in the dissolved sample to the pink endpoint. What is the percentage of iron in the unknown sample? Enter the percentage of iron in the space provided. Include 4 significant figures in your answer. Do not write any units! [Hint: Use your answer to Question 8! QUESTION 10 What is the percentage of Fe in iron(II) ammonium sulfate hexahydrate, Fe(NH 4) 2(SO 4) 2 6 H 20? Remember to account for the 6 waters of hydration when you calculate the molar mass of this compound!<\/p>\n\n\n\n
The Correct Answer and Explanation is :<\/strong><\/mark><\/p>\n\n\n\n Let’s go through the questions step by step and work out the correct answers:<\/p>\n\n\n\n We are given the volume and molarity of KMnO\u2084 solution:<\/p>\n\n\n\n To find the moles of MnO\u2084\u207b required for the titration:<\/p>\n\n\n\n [ [ Thus, the correct answer is 3.944 x 10\u207b\u2074 moles<\/strong>.<\/p>\n\n\n\n From the titration reaction, the stoichiometry is typically:<\/p>\n\n\n\n [ This means 1 mole of MnO\u2084\u207b reacts with 8 moles of Fe\u00b2\u207a. Therefore, using the moles of MnO\u2084\u207b from Question 6:<\/p>\n\n\n\n [ [ Thus, the correct answer is 1.972 x 10\u207b\u00b3 moles<\/strong>.<\/p>\n\n\n\n Now, we use the molar mass of Fe to convert moles of Fe\u00b2\u207a to grams. The molar mass of Fe is 55.845 g\/mol:<\/p>\n\n\n\n [ [ Thus, the mass of iron present in the sample is 0.1103 grams<\/strong>.<\/p>\n\n\n\n The total mass of the sample is given as 1.026 g. To find the percentage of iron in the sample:<\/p>\n\n\n\n [ [ Thus, the percentage of iron in the sample is 10.75%<\/strong>.<\/p>\n\n\n\n First, we need to calculate the molar mass of Fe(NH\u2084)\u2082(SO\u2084)\u2082\u00b76H\u2082O. Let’s break it down:<\/p>\n\n\n\n Now, adding these together:<\/p>\n\n\n\n [ [ Now, the percentage of Fe in the compound is:<\/p>\n\n\n\n [ [ Thus, the percentage of Fe in iron(II) ammonium sulfate hexahydrate is 14.25%<\/strong>.<\/p>\n\n\n\n A solid sample containing some Fe2+ ion weighs 1.026 g. It requires 26.54 mL of 0.01486 M KMnO4 to titrate the Fe2+ in the dissolved sample to the pink endpoint. How many moles of MnO4 are required? 9.860 x 10-5 moles 0.01486 moles 1.635 x 10-6 moles 3.944 x 10-1 moles 3.944 x 10-4 moles […]<\/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-189358","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/189358","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=189358"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/189358\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=189358"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=189358"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=189358"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}Solution to Questions<\/h3>\n\n\n\n
\n\n\n\nQuestion 6: How many moles of MnO\u2084\u207b are required?<\/strong><\/h3>\n\n\n\n
\n
\\text{Moles of } KMnO_4 = Molarity \\times Volume
]<\/p>\n\n\n\n
\\text{Moles of } KMnO_4 = 0.01486 \\, \\text{mol\/L} \\times 0.02654 \\, \\text{L} = 3.944 \\times 10^{-4} \\, \\text{mol}
]<\/p>\n\n\n\n
\n\n\n\nQuestion 7: How many moles of Fe\u00b2\u207a are present in this sample?<\/strong><\/h3>\n\n\n\n
\\text{MnO}_4^- + 8 \\, \\text{Fe}^{2+} + 4 \\, \\text{H}^+ \\rightarrow \\text{Mn}^{2+} + 5 \\, \\text{Fe}^{3+} + 2 \\, \\text{H}_2\\text{O}
]<\/p>\n\n\n\n
\\text{Moles of Fe}^{2+} = 8 \\times \\text{Moles of MnO\u2084\u207b}
]<\/p>\n\n\n\n
\\text{Moles of Fe}^{2+} = 8 \\times 3.944 \\times 10^{-4} = 3.155 \\times 10^{-3} \\, \\text{mol}
]<\/p>\n\n\n\n
\n\n\n\nQuestion 8: How many grams of iron are present in the sample?<\/strong><\/h3>\n\n\n\n
\\text{Mass of Fe} = \\text{Moles of Fe}^{2+} \\times \\text{Molar Mass of Fe}
]<\/p>\n\n\n\n
\\text{Mass of Fe} = 1.972 \\times 10^{-3} \\, \\text{mol} \\times 55.845 \\, \\text{g\/mol} = 0.1103 \\, \\text{g}
]<\/p>\n\n\n\n
\n\n\n\nQuestion 9: What is the percentage of iron in the unknown sample?<\/strong><\/h3>\n\n\n\n
\\text{Percentage of Fe} = \\frac{\\text{Mass of Fe}}{\\text{Total Mass of Sample}} \\times 100
]<\/p>\n\n\n\n
\\text{Percentage of Fe} = \\frac{0.1103}{1.026} \\times 100 = 10.75\\%
]<\/p>\n\n\n\n
\n\n\n\nQuestion 10: What is the percentage of Fe in iron(II) ammonium sulfate hexahydrate, Fe(NH\u2084)\u2082(SO\u2084)\u2082\u00b76H\u2082O?<\/strong><\/h3>\n\n\n\n
\n
\\text{Molar mass of Fe(NH\u2084)\u2082(SO\u2084)\u2082\u00b76H\u2082O} = 55.845 + 2 \\times 18.042 + 2 \\times 96.063 + 6 \\times 18.016
]<\/p>\n\n\n\n
= 55.845 + 36.084 + 192.126 + 108.096 = 392.151 \\, \\text{g\/mol}
]<\/p>\n\n\n\n
\\text{Percentage of Fe} = \\frac{\\text{Molar mass of Fe}}{\\text{Molar mass of Fe(NH\u2084)\u2082(SO\u2084)\u2082\u00b76H\u2082O}} \\times 100
]<\/p>\n\n\n\n
\\text{Percentage of Fe} = \\frac{55.845}{392.151} \\times 100 = 14.25\\%
]<\/p>\n\n\n\n
\n\n\n\nSummary of Answers:<\/h3>\n\n\n\n
\n