Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and beginning April 20th, 2021 (Eastern Time) the Yahoo Answers website will be in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.

Chemistry: stoichiometry?

What is the mass of excess reactant leftover if 20.0 grams of chromium reacts with 10.0 grams of copper II sulfate in the BALANCED reaction below?

Attachment image

1 Answer

  • 2 months ago
    Favorite Answer

    (20.0 g Cr) / (51.9961 g Cr/mol) = 0.384644 mol Cr

    (10.0 g CuSO4) / (159.6086 g CuSO4/mol) = 0.0626533 mol CuSO4

    0.0626533 mole of CuSO4 would react completely with 0.0626533 x (2/3) = 0.0417689 mole of Cr, but there is more Cr present than that, so Cr is in excess.

    ((0.384644 mol Cr initially) - (0.0417689 mol Cr reacted)) x (51.9961 g Cr/mol) =

    17.8 g Cr left over

Still have questions? Get your answers by asking now.