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Theoretical Yield, Molar Mass, and Percent Yield

  1. Feb 22, 2009 #1
    Hi, I have a few questions that I am struggling with. Any help would be greatly appreciated.

    Question 1
    Calculate the molar mass of calcium chloride dihydrate, CaCl2 • 2H2O.
    Please use the Periodic Table values rounded to the hundredths place for your calculation and round your answer to the hundredths place and remember, the "dot" (•) means closely associated, reprsenting the ADDITION of two waters of hydration to the calcium chloride formula unit.

    Question 2
    What is the theoretical yield of calcium carbonate if 2.97 grams of calcium chloride dihydrate reacts with excess sodium carbonate according to the balanced chemical reaction shown below?

    Please use molar mass values calculated and rounded to the hundredths place, and round your answer to the hundredths place.

    Question 3
    What is the percent yield of calcium carbonate if your theoretical yield was 2.07 grams, and your actual yield was 1.46 grams, from the balanced chemical reaction shown below?
    Please round your answer to the tenths place.
  2. jcsd
  3. Feb 24, 2009 #2
    1) Simply use the molar masses provided by the periodic table to calculate the molar mass. So you'd take 40.00g (Ca) +2(35.45g Cl) + 4(1.01g H) + 2(16.00g) to find your molar mass.

    2) Divide 2.97 g by the molar mass of CaCl2•2H20(aq) you got in 1). Using stoichiometry, CaCl2•2H20(aq) to CaCO3(aq) is a 1:1 ratio, which means your theoretical yield would be whatever answer you got from 2.97g/Molar Mass of CaCl2•2H20(aq).

    3) Percent Yield = ( Actual Yield / Theoretical Yield ) x 100%
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