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Homework Help: Limiting and Excess Reactants in Redox

  1. Oct 16, 2008 #1
    1. The problem statement, all variables and given/known data
    Suppose 1.00g of Mn Reacts with an excess of 6.00M HCl, how many grams of H2 gas is produced?
    What volume hydrogen gas is produced by this reaction?

    2. Relevant equations
    density of hydrogen gas is 0.08988g/L
    conditions: 0 degrees celsius, 1 atm pressure

    3. The attempt at a solution

    First I wrote the reaction out

    2Mn +6HCl -> 2MnCl3 +3H2

    Then this is where I ran into some confusion. Does the 6.00M solution have any effect on the amount of hydrogen produced? I assumed it did not and then went on to find the moles of Mn ( 0.0182 mol) and used the molar ratio of 2:3 to find out the moles of hydrogen gas (0.0273 mol).

    I then determined the grams of hydrogen gas and then used a comparison ratio between it and the density of hydrogen gas to find the volume which I determined to be 0.612L.

    I just require some verification, from what I remember the limiting reactant is what determines the amount of moles produced
  2. jcsd
  3. Oct 16, 2008 #2


    User Avatar

    Staff: Mentor

    You are OK being wrong :wink:

    Calculations are correct, but I doubt you will be able to oxidize Mn to Mn3+ with hydrochloric acid.
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