In a process, 646 g of ammonia is allowed to react with 1.144 kg of `CO_(2)` to form urea.
(i) If the entire quantity of all the reactants is not consumed in the reaction which is the limiting reagent ?
(ii) Calculate the quantity of urea formed and unreacted quantity of the excess reagent. The balanced equation is
`underset (H_(2)NCONH_(2) + H_(2)O)(2NH_(3) + CO_(2))`

Explanation

(i) The entire quantity of ammonia is consumed in the reaction. So ammonia is the limiting reagent. Som,e quantity of `CO_(2)` remains unreacted, so `CO_(2)` is the excess reagent.
(ii) Quantity of urea formed = number of moles of urea formed x molar mass of urea = 19 moles `xx 60 g mol^(-1)`
= 1140 g = 1.14kg
Excess reagent leftover at the end of the reaction is carbon dioxide. Amount of carbon dioxide leftover = number of moles of CO, left over x molar mass of `CO_(2)` = `7 "moles" xx 44 g mol^(-1)` = 308 g.