Answer
%Yield = 87.2%
Explanation
Given:
mass of NH3 reacted = 73 g
mass of H2O produced = 101 g
We know:
molar mass of NH3 = 17,031 g/mol
molar mass of water = 18.01528 g/mol
Required: % Yield
Solution:
The formula used to calculate the percentage yield is:
%Yield = (actual yield/theoretical yield) x 100
The actual yield of H2O produced = 101 g
Now lets calculate the theoretical yield first.
First find the number of moles of NH3, and use stoichiometry to find the theoretical mass of water.
n = m/M n is the moles, m is the mass and M is the molar mass.
n = 73/17,031 g/mol
n = 4.29 mol
Using the stoichiometry, there molar ratio between NH3 and H2O is 4:6
Therefore the moles of H2O = 4.29 x (6/4)
n of H2O = 6.43 mol
The theoretical mass can then be calculated:
m = n x M
m = 6.43 mol x 18.01528 g/mol
m = 115.83 g
%Yield = (101 g/115.83)*100
%Yield = 87.2%
