U.S. Lime & Minerals is a company that produces quicklime, CaO, by heating calcium hydroxide, Ca(OH)₂. What is the percent yield if 45 grams of quicklime are obtained from 1 mole of calcium hydroxide? A)61% B)80% C)45% D)100% E)90%

Question

Quizplus · Accepted Answer

To calculate percent yield, we need to compare the actual yield to the theoretical yield. The theoretical yield is the amount of product that should be obtained based on stoichiometry and assuming a 100% conversion.

1 mole of Ca(OH)2 produces 1 mole of CaO. The molar mass of Ca(OH)2 is approximately 74 g/mol, so 1 mole is equal to 74 grams.

Therefore, the theoretical yield of CaO from 74 grams of Ca(OH)2 would be 74 grams.

However, the actual yield is only 45 grams.

percent yield = (actual yield/theoretical yield) x 100%
percent yield = (45/74) x 100% = 60.8%

So, the closest answer choice is B, 80%.

US Lime & Minerals Is a Company That Produces Quicklime