posted by lorah hilpolep on .
Determine the mass of water formed when 14.5L NH3 (at 298K and 1.5 atm) is reacted with 19.3 L of O2 (at 321K and 1.2 atm)
This is a limiting reagent problem. How do I know that? Because BOTH reacts are given.
Use PV = nRT to determine moles NH3.
Use PV = nRT to determine moles O2.
Using the coefficients in the balanced equation, convert moles NH3 to moles H2O.
Do the same to convert moles O2 to moles H2O. The answer for moles H2O probably will not agree which means one of them is wrong; the correct answer in limiting reagent problems is ALWAYS the smaller value and the reagent providing that answer is the limiting reagent.
Using the smaller number, convert moles H2O to grams H2O. g = moles x molar mass.