1. The problem statement, all variables and given/known data Ammonia burns in air to form nitrogen dioxide and water 4NH3(g) + 7O2(g) --> 4NO2(g) + 6H2O(l) If 8 moles of NH3 are reacted with 14 moles of O2 in a rigid container with an initial pressure of 11 atm, what is the partial pressure of NO2 in the container when the reaction runs to completion? (assume constant temperature) 3. The attempt at a solution This is what i did: i used PV = nRT.... since T, R, and V are constant here, I said Pinitial/ ninitial = Pfinal/nfinal I used 11 atm for P initial and I added the moles of the 2 reactant gases for the initial n to get 8+14 = 22. (is this allowed? Can I add the 2 moles of gases together for this problem even though they are different gases?) Then I used 8 moles for my final n (since 8 moles of NO2 were formed) and then calculated 4 atm as my answer for the final partial pressure of NO2. Is there a faster/ easier way to calculate the answer? Did I do it the right way?