### Video Transcript

The following equation shows the
production of urea, CO(NH2)2, a fertilizer often made at plants where the Haber
process is running: πNH3 plus Y reacts to produce CO(NH2)2 plus Z. Which of the following replaces π,
Y, and Z in the equation? (A) π is two, Y is CO, Z is
H2. (B) π is two, Y is HNCO, and Z is
H2O. (C) π is one, Y is (NH4)2CO3, and
Z is H2. (D) π is one, Y is H2CO3, and Z is
H2O. Or (E) π is two, Y is CO2, and Z
is H2O.

In this question, we need to
complete the equation for the production of urea from ammonia and an unidentified
molecule. Ammonia is a valuable substance
made during the Haber process. It is an important nitrogenous
fertilizer that can be used to generate other fertilizers such as urea. Carbon dioxide is reacted with
ammonia to produce urea. So we can already tell that the
answer will be option (E). But for completeness, letβs balance
the equation and work out what unknowns π and Z represent.

Letβs tally how many of each atom
we have on the reactants and products side. If we start with nitrogen atoms, we
can see that there is only one on the reactants side but two on the products. If we have two equivalents of
ammonia, the nitrogen atoms are now balanced. To make the overall equation
balanced, we need two hydrogens atoms and one oxygen. So an equivalent of water would
balance the equation. We can therefore see that two
equivalents of ammonia react with one equivalent of carbon dioxide to produce one
equivalent of urea and one equivalent of water.

Therefore, the correct answer is
(E): π is two, Y is CO2, and Z is H2O.