What mass of melamine, C3N3(NH2)3, will be obtained from 159.5 kg of urea, CO(NH2)2, if the yield of the overall reaction is 79.0 %?
Just follow the steps.
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To determine the mass of melamine obtained from urea, you need to consider the balanced chemical equation and the molar masses of the compounds involved.
First, let's write the balanced chemical equation for the reaction:
2CO(NH2)2 → C3N3(NH2)3 + 3NH3
According to the balanced equation, 2 moles of urea (CO(NH2)2) react to form 1 mole of melamine (C3N3(NH2)3) and 3 moles of ammonia (NH3).
Next, calculate the molar masses of urea and melamine:
Molar mass of urea (CO(NH2)2):
C: 12.01 g/mol × 1 = 12.01 g/mol
O: 16.00 g/mol × 1 = 16.00 g/mol
N: 14.01 g/mol × 2 = 28.02 g/mol
H: 1.01 g/mol × 4 = 4.04 g/mol
Total molar mass = 60.07 g/mol
Molar mass of melamine (C3N3(NH2)3):
C: 12.01 g/mol × 3 = 36.03 g/mol
N: 14.01 g/mol × 6 = 84.06 g/mol
H: 1.01 g/mol × 9 = 9.09 g/mol
Total molar mass = 129.18 g/mol
Now, let's calculate the theoretical yield of melamine:
Given: Mass of urea = 159.5 kg
Percentage yield = 79.0%
Convert the mass of urea to grams:
159.5 kg × 1000 g/kg = 159,500 g
Calculate the moles of urea:
moles of urea = mass of urea / molar mass of urea
moles of urea = 159,500 g / 60.07 g/mol = 2655.82 mol
According to the balanced equation, the molar ratio between urea and melamine is 2:1. So, the moles of melamine formed will be half of the moles of urea:
moles of melamine = moles of urea / 2
moles of melamine = 2655.82 mol / 2 = 1327.91 mol
Finally, calculate the mass of melamine by multiplying the moles by the molar mass:
mass of melamine = moles of melamine × molar mass of melamine
mass of melamine = 1327.91 mol × 129.18 g/mol = 171,302.89 g
To convert the mass to kilograms:
mass of melamine = 171,302.89 g / 1000 = 171.30 kg
Therefore, the mass of melamine obtained from 159.5 kg of urea, with a yield of 79.0%, is approximately 171.30 kg.