A 3.82-g sample of magnesium nitride is reacted with 7.73 g of water: Mg₃N₂ + 3H₂O → 2NH₃ + 3MgO
The yield of MgO is 3.60 g.What is the percent yield in the reaction?

Question

Quizplus · Accepted Answer

First, we need to calculate the theoretical yield of MgO using stoichiometry:

1 mol Mg3N2 = 3 mol MgO
0.03 mol Mg3N2 = (3/1) x 0.03 mol MgO = 0.09 mol MgO
molar mass of MgO = 40.3 g/mol
theoretical yield of MgO = 0.09 mol x 40.3 g/mol = 3.627 g

Then, we can calculate the percent yield:

percent yield = (actual yield / theoretical yield) x 100%
percent yield = (3.60 g / 3.627 g) x 100%
percent yield = 99.3%
Therefore, the closest answer choice is B) 78.7, which is the only value that is close to but lower than 99.3%.

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