Calculations Involving Consecutive Reactions

Melamine, C3N3(NH2)3, is used in adhesives and resins. It is manufactured in a two-step process in which urea, CO(NH2)2, is the sole starting material, isocyanic acid, HNCO, is an intermediate, and ammonia, NH3, and carbon dioxide, CO2, gases are byproducts.

In the first step of this reaction, urea is broken down into isocyanic acid and ammonia:

CO(NH2)2(l)→HNCO(l)+NH3(g)

In the second step of this reaction, isocyanic acid reacts to form melamine and carbon dioxide:

HNCO(l)→C3N3(NH2)3(l)+CO2(g)

Balance this reaction and enter the coefficients below.

What mass of melamine, C3N3(NH2)3, will be obtained from 124.0kg of urea, CO(NH2)2, if the yield of the overall reaction is 84.0% ?