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 142.1 kg of ammonia with 211.4 kg of carbon dioxide and obtains 171.4 kg of urea. Part A Determine the limiting reactant. Express your answer as a chemical formula.

Answer 1

Answer:

The limiting reactant is Carbon dioxide, $CO_{2}$

Explanation:

The balanced reaction equation is:

$2NH_{3} + CO_{2}$ → $CH_{4} N_{2} O + H_{2} O$

The mole ratio of ammonia to carbon dioxide is 2:1

142100/17g = 8358.8 mol of NH3

211400/44g = 4, 804.5 mole of CO2

Now:

4,804.5 mol of CO2 × $\frac{2 mol NH_{3} }{1 molCO_{2} }$ = 9,609 mol of NH3  present

8,358.8 mole of NH3 × $\frac{1 moleCO_{2} }{2moles NH_{3} }$ = 4,179.4 mol of CO2 present

NH3 needs 8, 358.8 moles but had 9, 609 moles⇒ excess reactant

CO2 needs 4, 804,5 mol but had 4, 179.4 moles⇒ limiting reactant (used up completely)

The limiting reactant is carbon dioxide, CO2.