Calcium oxide reacts with water in a combination reaction to produce calcium hydroxide:
CaO(s) + H₂O(l) → Ca(OH) ₂(s)
In a particular experiment,a 5.00 g sample of CaO is reacted with excess water and 6.11 g of Ca(OH) ₂ Is recovered.What is the percent yield in this experiment?

Question

Quizplus · Accepted Answer

First, we need to calculate the theoretical yield of Ca(OH)2 using stoichiometry:

1 mol CaO yields 1 mol Ca(OH)2 
molar mass of CaO = 56.08 g/mol 
molar mass of Ca(OH)2 = 74.09 g/mol

5.00 g CaO x (1 mol CaO/56.08 g) x (1 mol Ca(OH)2/1 mol CaO) x (74.09 g Ca(OH)2/1 mol Ca(OH)2) = 6.60 g Ca(OH)2 (theoretical yield)

Now we can calculate the percent yield:

% yield = (actual yield / theoretical yield) x 100% 
% yield = (6.11 g / 6.60 g) x 100% = 92.5%

Therefore, the best choice is D, with a percent yield of 92.5%.

Calcium Oxide Reacts with Water in a Combination Reaction to Produce