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 1.00-g sample of CaO is reacted with excess water and 0.82 g of Ca(OH)2 is recovered. What is the percent yield in this experiment?
each mole of CaO produces one mole of Ca(OH)2
1mole of CaO is 56g, so you have 0.0178 moles of CaO
0.0178 moles of Ca(OH)2 is 1.321g
so the yield is
0.82/1.321 = 0.62 = 62%