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##### chemistry question about limited reactants and percent yield

 Chemistry Tutor: None Selected Time limit: 1 Day

what mass of water forms when solutions containing 3.27 g of hydrochloric acid and 7.62 g of calcium hydroxide are mixed?

what does it mean "what mass of water?" do I find the limited reactant first or does this question deal with percent yield?

Apr 13th, 2015

---The first step will be to write out the balanced chemical reaction that occurs when hydochloric acid and calcium hydroxide are added.

2 HCl (aq) + Ca(OH)2 (aq) =====> CaCl2 (aq) + 2 H2O (l)

---The next step would be to determine which of the reactants is the limiting reactant.

3.27 g HCl * 1 mol / 36.46 g = 0.08976 mol HCl

7.62 g Ca(OH)2 * 1 mol / 74.093 g = 0.10284 mol Ca(OH)2

Compare molar ratios

0.08976 mol HCl / 0.10284 mol Ca(OH)2 = 0.872

From equation 2 mol HCl / 1 mol Ca(OH)2 = 2

Since the molar ratio is much less than the theoretical, the HCl will be the limiting reagent.

(There are other ways to determine the limiting reagent.  If you are familiar with another process this is just another way it can be done.  If you would like more details please let me know.)

---The final part will be to determine mass of water that can be produced by the limiting reagent.

0.08976 mol HCl * 2 mol H2O / 2 mol HCl * 18.015 g H2O / 1 mol = 1.617 g H2O produced.

Apr 13th, 2015

Percent yield is used to compare actual results from a reaction formed in the laboratory to the theoretical yield.  What was calculated above is the theoretical yield for the given amounts of reactants.  If you knew how much water was actually produced from that equation, then you could calculate the percent yield.

Apr 13th, 2015

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Apr 13th, 2015
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Apr 13th, 2015
Dec 8th, 2016
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