The Grass Doctor

pls help me, i need help with this problem?

Urea (H2NCONH2) is used extensively as a nitrogen source in fertilizers. It is produced commercially from the reaction of ammonia and carbon dioxide. 2 NH3(g) + CO2(g) >H2NCONH2(s) + H2O(g) Ammonia gas at 223°C and 90. atm flows into a reactor at a rate of 610. L/min. Carbon dioxide at 223°C and 48 atm flows into the reactor at a rate of 600. L/min. What mass of urea is produced per minute by this reaction assuming 100% yield? g/min

Public Comments

1. forget about the /min stuff- everything we're dealing with has that unit, so you can ignore it. So what g of urea is produced? How would one find that? 1) identify limiting reagent 2) how ever many moles in limiting reagent are used determines moles of urea (not necesarily 1:1 ratio- must look at reaction equation) 3) then, moles of urea are known 4) moles of urea converts to g with molecular weight of urea 1) what's the limiting reagent? The one with the least amount of moles on the left side of equation. How can we figure out moles of those? do a PV=nRT for NH3, as well as a PV=nRT for CO2. All variables are known but n. Ex: Ammonia: P= 90 atm V= 610L R=.08blabla look up the gas constant that has L and atm in it... and T= 223C + 273K. Doing this for ammonia, and then appropriate # for CO2 will give you -----moles NH3 and -----moles CO2. If it ends up being exactly 2 NH3: 1CO2, or some multiple like 1:0.5....200:100, then no worry, they are both the limiting reagent and whatever moles of CO2 is = moles urea. But if it's something like 1.5 NH3 : 1CO2, then NH3 is limiting, since it needs to have a 2:1 ratio, if it's 2.1 NH3: 1 CO2, then it's CO2 that is the limiting one. 2,3) If CO2 is limiting reagent, that's easy... since there is one mole CO2 for one mole Urea, then whatever moles of CO2 is, that's same for Urea... if limiting reagent is NH3, then take that # of moles, and divide by 2 since there's 2 ammonia needed for one urea. 4) add up elements of urea to get molecular weight and do moles urea X g/mols urea = g urea... DONE!