Calcium oxide reacts with water in a combination reaction to produce calcium hydroxide: CaO(s)+ O(l)→ (s)
In a particular experiment,a 5.50-g sample of CaO is reacted with excess water and 6.77 g of is recovered.What is the percent yield in this experiment?

Question

Calcium oxide reacts with water in a combination reaction to produce calcium hydroxide: CaO(s)+  O(l)→  (s)
In a particular experiment,a 5.50-g sample of CaO is reacted with excess water and 6.77 g of  is recovered.What is the percent yield in this experiment?

Quizplus · Accepted Answer

To calculate the percent yield, we need to use the actual yield (what was recovered in the experiment) and the theoretical yield (what we would expect to get based on stoichiometry), and use the formula: percent yield = (actual yield/theoretical yield) x 100%.

First, we need to calculate the theoretical yield of calcium hydroxide. The balanced equation tells us that for every 1 mole of CaO, we should get 1 mole of Ca(OH)2. The molar mass of CaO is 56.08 g/mol, so the number of moles of CaO in 5.50 g is:

5.50 g CaO x (1 mol CaO/56.08 g CaO) = 0.0981 mol CaO

Therefore, the theoretical yield of Ca(OH)2 is also 0.0981 mol. The molar mass of Ca(OH)2 is 74.09 g/mol, so the theoretical yield in grams is:

0.0981 mol Ca(OH)2 x (74.09 g Ca(OH)2/mol) = 7.27 g Ca(OH)2

Now we can calculate the percent yield:

percent yield = (actual yield/theoretical yield) x 100%
percent yield = (6.77 g/7.27 g) x 100%
percent yield = 93.1%

Therefore, the percent yield is 93.1%, which is choice D.

Calcium Oxide Reacts with Water in a Combination Reaction to Produce