Question

Part A Melamine, C3Ns (NH2)3, is used in adhesives and resins. It is manufactured in a two-step process in which urea, CO(NH)2 is the sole starting material, isocyanic acid. HNC0, is an ntermed ate, and ammonia. NHs. and carbon dioxide, CO2. gases are byproducts In the second step of this reaction, isocyanic acid reacts to form melamine and carbon dioxide Balsnce this resction and enter the coefficients below. Enter the coefficients in order separated by commas (e.g, 1,4,5, where 1 indicates the lack of a coefficient) View Available Hint(s) 6,1,3 VCorrect Thus. the two-step process can be written as 1. CO(NH2)21) HNCO)NHs() 3CO2(g) Part B What mass of melamine. CsNs (NH2)3 . wil be obtained from 162.5 kg of urea. CO(NH2 )2-if the yield of the overall reaction is 81.0 % ? Express your answer to three significant figures and include the appropriate units View Available Hint(s) Value Units

Answer 1

From the two step reaction, it can be inferred that one equivalent of urea gets converted into one equivalent isocyanuric acid while 6 eq of isocyanuric acid is required to make 1 eq of melamine. Thus one can determine that 6 moles of urea is required to produce 1 mole of melamine.

Now, the no.of moles of urea in 162.5kg of urea with a molar mass of 60.06g/mol gives 162500/60.06 = 2705.6277moles. Dividing by six, it gives 490.9379moles of melamine if the reaction gives 100% yield. However, since the overall yield is given to be 81%, the expected moles of melamine will be 81% of 450.9379 which is 365.2597moles. Now, from the molar mass of melamine as 126.12g/mol, the mass of melamine produced from 162.5kg of urea is 126.12*365.2597 = 46.066kg.