Consider the given balanced chemical equation: 2H2 + O2 gives 2H2O. If 4 g of H2 reacts with 32 g of O2 to produce 28 g of H2O, what is the percentage yield of the reaction? (Molar mass of H2 = 2 g/mol, O2 = 32 g/mol and H2O = 18 g/mol)
- A. 63.6%
- B. 77.8%
- C. 87.5%
- D. 92.5%
Explanation
Four grams of hydrogen is 2 moles and 32 g of oxygen is 1 mole, which is exactly the 2 to 1 ratio the equation requires, so neither is in excess and 2 moles of water should form, that is 36 g. The percentage yield is therefore 28 divided by 36 multiplied by 100, which is 77.8 per cent. Checking for a limiting reactant before computing the theoretical yield is the step most often skipped.
Related questions
The theoretical yield of a reaction is
A reaction has a theoretical yield of 25 g but only 20 g of product is obtained. The percentage yield is
The actual yield of a reaction is usually less than the theoretical yield for all of the following reasons EXCEPT
How many grams of calcium oxide are produced when 1 mole of calcium carbonate decomposes completely, given CaCO3 gives CaO + CO2?
If % yield and actual yield is 80 and 20 g respectively, what will be theoretical yield?