Question

Urea (CH4N2O) is a common fertilizer that can be synthesized by the reaction of ammonia (NH3) with carbon dioxide as follows:

2NH3(aq)+CO2(aq)→CH4N2O(aq)+H2O(l)

In an industrial synthesis of urea, a chemist combines 128.9 kg of ammonia with 211.4 kg of carbon dioxide and obtains 166.3 kg of urea.

Determine the theoretical yield of urea

Answer 1

The theoretical yield of urea : = 227.4 kg

Further explanation

Given

Reaction

2NH3(aq)+CO2(aq)→CH4N2O(aq)+H2O(l)

128.9 kg of ammonia

211.4 kg of carbon dioxide

166.3 kg of urea.

Required

The theoretical yield of urea

Solution

mol Ammonia (MW=17 g/mol)

=128.9 : 17

= 7.58 kmol

mol CO₂(MW=44 g/mol) :

= 211.4 : 44

= 4.805 kmol

Mol : coefficient of reactant , NH₃ : CO₂ :

= 7.58/2 : 4.805/1

=3.79 : 4.805

Ammonia as limiting reactant(smaller ratio)

Mol urea based on mol Ammonia :

=1/2 x 7.58

=3.79 kmol

Mass urea :

=3.79 kmol x 60 g/mol

= 227.4 kg