Calcium oxide reacts with water in a combination reaction to produce calcium hydroxide: CaO(s) + O(l) → (s)
In a particular experiment, 5.00 g sample of CaO is reacted with excess water and 6.11 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, 5.00 g sample of CaO is reacted with excess water and 6.11 g of  is recovered. What is the percent yield in this experiment?

Quizplus · Accepted Answer

To calculate the percent yield, we need to compare the actual yield (6.11 g) to the theoretical yield. 
From the balanced equation, we can see that 1 mol of CaO reacts with 1 mol of water to produce 1 mol of Ca(OH)2. Therefore, we can use the molar mass of CaO to calculate the theoretical yield:

5.00 g CaO * (1 mol CaO/56.08 g CaO) * (1 mol Ca(OH)2/1 mol CaO) * (74.09 g Ca(OH)2/1 mol Ca(OH)2) = 6.66 g Ca(OH)2

Now we can calculate the percent yield:

(6.11 g actual yield / 6.66 g theoretical yield) * 100% = 91.7%

Rounding to one decimal place gives us the closest answer choice, which is E (92.5%).

Calcium Oxide Reacts with Water in a Combination Reaction to Produce