{"id":223863,"date":"2025-06-02T12:30:48","date_gmt":"2025-06-02T12:30:48","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=223863"},"modified":"2025-06-02T12:30:50","modified_gmt":"2025-06-02T12:30:50","slug":"nickelii-ions-in-solution-will-form-an-insoluble-complex-with-dimethylglyoxime","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/06\/02\/nickelii-ions-in-solution-will-form-an-insoluble-complex-with-dimethylglyoxime\/","title":{"rendered":"Nickel(II) ions in solution will form an insoluble complex with dimethylglyoxime"},"content":{"rendered":"\n

Nickel(II) ions in solution will form an insoluble complex with dimethylglyoxime: nickel bis(dimethylglyoximate), Ni(C4H7O2N2)2. If a gravimetric analysis of Ni results in 0.6531 g of Ni(C4H7O2N2)2, what was the original mass of Ni2+ in the sample solution? Ni(C4H7O2N2)2 FW 288.9172 g\/mol Ni FW 58.693 g\/mol
Nickel(II) ions in solution will form an insoluble complex with dimethylglyoxime: nickel bis(dimethylglyoximate), Ni(C4H7O2N2)2. If a gravimetric analysis of Ni results in 0.6531 g of Ni(C4H7O2N2)2, what was the original mass of Ni2+ in the sample solution? Ni(C4H7O2N2)2 FW 288.9172 g\/mol Ni FW 58.693 g\/mol<\/p>\n\n\n\n

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

Answer: 0.1327 g Ni\u00b2\u207a (to four significant figures)<\/strong><\/p>\n\n\n\n

\n\n\n\n

Explanation <\/strong><\/p>\n\n\n\n

Gravimetric analysis converts the analyte into a solid of known, reproducible composition. In this case each Ni\u00b2\u207a ion is precipitated by dimethyl\u00adglyoxime (DMG) to form a 1-to-1 chelate, nickel bis(dimethyl\u00adglyoximate), whose formula is Ni(C\u2084H\u2087O\u2082N\u2082)\u2082. Because the stoichiometry in the solid is fixed\u2014exactly one Ni atom per formula unit\u2014the mass of the precipitate can be related directly to the mass of nickel that was present in the original solution.<\/p>\n\n\n\n

    \n
  1. Determine moles of precipitate.<\/strong> nppt=mpptMppt=0.6531\u2005\u200ag288.9172\u2005\u200ag\u00a0mol\u22121=2.261\u00d710\u22123\u2005\u200amoln_{\\text{ppt}}=\\frac{m_{\\text{ppt}}}{M_{\\text{ppt}}} =\\frac{0.6531\\;\\text{g}}{288.9172\\;\\text{g mol}^{-1}} =2.261\\times10^{-3}\\;\\text{mol}<\/li>\n\n\n\n
  2. Convert moles of precipitate to moles of Ni.<\/strong>
    The formula contains one Ni per molecule, so nNi=nppt=2.261\u00d710\u22123\u2005\u200amoln_{\\text{Ni}}=n_{\\text{ppt}}=2.261\\times10^{-3}\\;\\text{mol}<\/li>\n\n\n\n
  3. Convert moles of Ni to mass of Ni.<\/strong> mNi=nNi\u2005\u200aMNi=(2.261\u00d710\u22123\u2005\u200amol)(58.693\u2005\u200ag\u00a0mol\u22121)=0.1327\u2005\u200agm_{\\text{Ni}}=n_{\\text{Ni}}\\;M_{\\text{Ni}} =(2.261\\times10^{-3}\\;\\text{mol})(58.693\\;\\text{g mol}^{-1}) =0.1327\\;\\text{g}<\/li>\n<\/ol>\n\n\n\n

    Only three arithmetic steps are needed because the chemical reaction has a simple 1:1 stoichiometry: Ni(aq)2++2\u2009DMG(alc)\u2005\u200a\u27f6\u2005\u200aNi(DMG)2\u2009(s)+2\u2009H(aq)+\\text{Ni}^{2+}_{(aq)} + 2\\,\\text{DMG}_{(alc)} \\;\\longrightarrow\\; \\text{Ni(DMG)}_{2\\,(s)} + 2\\,\\text{H}^{+}_{(aq)}<\/p>\n\n\n\n

    Every mole of solid isolated therefore \u201crepresents\u201d exactly one mole of Ni\u00b2\u207a that had been dissolved.<\/p>\n\n\n\n

    Why use gravimetry?<\/strong>
    Gravimetric methods are valued for their accuracy: once the precipitate is thoroughly washed, dried (or gently ignited), and weighed, the calculation requires only reliable atomic-mass data. No calibration standards or instrumentation beyond an analytical balance are needed, and systematic errors are minimized because the mass ratio between the precipitate and the analyte is fixed by stoichiometry, not by instrumental response factors.<\/p>\n\n\n\n

    Significant-figure check.<\/strong>
    The precipitate mass is given to four significant figures (0.6531 g), so reporting 0.1327 g\u2014for which the final digit is uncertain by at most \u00b11 in the last place\u2014maintains the proper precision.<\/p>\n\n\n\n

    Hence the original sample solution contained 0.1327 g of Ni\u00b2\u207a<\/strong>.<\/p>\n\n\n\n

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

    Nickel(II) ions in solution will form an insoluble complex with dimethylglyoxime: nickel bis(dimethylglyoximate), Ni(C4H7O2N2)2. If a gravimetric analysis of Ni results in 0.6531 g of Ni(C4H7O2N2)2, what was the original mass of Ni2+ in the sample solution? Ni(C4H7O2N2)2 FW 288.9172 g\/mol Ni FW 58.693 g\/molNickel(II) ions in solution will form an insoluble complex with dimethylglyoxime: […]<\/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-223863","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/223863","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=223863"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/223863\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=223863"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=223863"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=223863"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}