The electrolysis of water forms H2 and O2.

2H2O → 2H2 + O2

What is the percent yield of Oz if 10.2 g of Oz is produced from the decomposition of 17.0 g of H20?

Actual yield

Use %Yield = =

Theoretical yield To

15.1%

33.8%

60.1%

67.6%

67.5% ≅ 67.6%

Explanation:

Given dа ta:

Mass of water = 17.0 g

Mass of oxygen produced (actual yield) = 10.2 g

Percent yield of oxygen = ?

Solution:

Chemical equation:

2H₂O → 2H₂ + O₂

Number of moles of water:

Number of moles = mass / molar mass

Number of moles = 17.0 g / 18.016 g/mol

Number of moles = 0.944 mol

Now we will compare the moles of oxygen with water to know the theoretical yield of oxygen.

H₂O : O₂

2 : 1

0.944 : 1/2*0.944 = 0.472 mol

Mass of oxygen:

Mass = number of moles * molar mass

Mass = 0.472 mol * 32 g/mol

Mass = 15.104 g

Percent yield:

Percent yield = [Actual yield / theoretical yield] * 100

Percent yield = [ 10.2 g / 15.104 g] * 100

Percent yield = 0.675 * 100

Percent yield = 67.5%