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Easy Stoichiometry Concentration Problem

  1. Jan 5, 2016 #1
    1. A piece of iron was added to a beaker that contained 0.585 mol/L copper(II) sulfate, CuSO4(aq). The solid copper that precipitated was dried, and its mass was found to be 5.02 g. Some unreacted iron remained in the beaker. Calculate the minimum volume of the copper(II) sulfate solution.

    I really have no idea what I'm doing, seriously. I pretty much just guessed and my answer is almost guaranteed to be completely wrong.

    This is what I have:

    0.585mol CuSO4 / 1 L = 1 mol Cu / 1 mol CuSO4 = x / 5.02g Cu = 5.02g CuSO4
    n=5.02g CuSO4 / 159.62 g/mol = 0.031 mol CuSO4
    v = 0.585mol / L / 0.031 mol
    v = 18.4 L.

    2. To generate hydrogen gas, a teacher added 25.0 g of mossy zinc to 220 mL of 3.00 mol/L hydrochloric acid in an Erlenmeyer flask.

    a. What mass of hydrogen gas was generated?

    b. Aft er the reaction, what was the concentration of zinc chloride, ZnCl2(aq), in the fl ask?

    Again I honestly have no idea what to do for this problem, I don't even know how to start....
  2. jcsd
  3. Jan 5, 2016 #2


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    One step at a time: mixing "run-on" notation with conventional notation is a no-no. 0.031 moles? Maybe. 18.4 l? No.

    What's the "molecular mass" for hydrogen?
  4. Jan 6, 2016 #3
    What do you mean by "run on" notation? and H=1.01g/mol
  5. Jan 12, 2016 #4
    Make sure you take into account that hydrogen is a diatomic gas H2 so the molecular mass for hydrogen is 2.02 amu
  6. Jan 13, 2016 #5


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    Staff: Mentor

    How many moles of copper were produced?

    How many moles of copper sulfate were needed for that?

    What volume of 0.585 M copper sulfate solution contains this number of moles?
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