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Homework Help: Chemistry stoichiometry?

  1. Sep 15, 2009 #1
    1. Chromium(III) Oxide reacts with Hydrogen Sulfide(H2S) gas to form Chromium Sulfide and water.

    CR2O3(s) + H2S(g) = Cr2S3(s) + H2O (l)

    to produce 439g of Cr2S3.

    a. How many moles of Cr2O3 are required?

    b. How many grams of CR2O3 are required?

    2. Not sure how to set this up

    3. All I could think of was finding the total grams of CR2O3 and dividing it from 439g's to find part a, but I think I was wrong
  2. jcsd
  3. Sep 15, 2009 #2


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    Identify the ratios from the written reaction. Calculate the formula weights for the relevant compounds.
  4. Sep 17, 2009 #3
    For part A: Find out how moles of Cr2S3 are in 439 g and the answer is how many moles of Cr2O3 because the mole:mole ratio is 1:1.

    For part B: Calculate how many grams of Cr2O3 are in your answer to part a
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