The balanced equation for the reaction is:
6 HNCO(l) → C3N3(NH2)3(l) + 3 CO2(g)
Convert amount of urea from kg to moles
Molar Mass of urea = 60.06 g/mol so, 113 kg urea contains
113 kg / 60.06 = 1.88 mol urea
From balanced equation 6 moles of urea yields only 1 melamine, so divide the moles of urea by 6.
1.88 / 6 = 0.313 kmol melamine
Now multiply 0.313 with molar mass of melamine that is 126 g/mol
126 x 0.313 = 39.438 kg
Yield of overall reaction is 73% so multiply 39.438 with 0.73
39.438 x 0.73 = 28.799 kg is the answer
