What mass of melamine, C3N3(NH2)3, will be obtained from 112.5 kg of urea, CO(NH2)2, if the yield of the overall reaction is 85.0 % ? Express your answer to three significant figures and include the appropriate units.

1 Answer
Feb 16, 2018

The mass of melamine is 33.5 kg.

Explanation:

The equation for the synthesis of melamine is

#M_text(r):color(white)(mm)60.06color(white)(mmmmm)126.12#
#color(white)(mmm)"6CO"("NH"_2)_2 → "C"_3"N"_3("NH"_2)_3 + "6NH"_3 + "3CO"_2#

Step 1. Calculate the theoretical yield of melamine

#"Theor. yield" = 112.5 color(red)(cancel(color(black)("kg urea" )))× (1 color(red)(cancel(color(black)("kmol urea"))))/(60.06 color(red)(cancel(color(black)("kg urea")))) × (1 color(red)(cancel(color(black)("kmol melamine"))))/(6 color(red)(cancel(color(black)("kmol urea")))) × "126.12 kg melamine"/(1 color(red)(cancel(color(black)("kmol melamine")))) = "39.37 kg melamine"#

Step 2. Calculate the actual yield of melamine

#"Actual yield = 0.850 × 39.37 kg = 33.5 kg"#