Chem
posted by Connie .
How many grams of N2 are produced when 125g of NH3 reacts by the following? 4NH3+6NO>5N2 +6H20
I know the answer but I do not know how to do the problem. The answer in the book is 257g
But what do I do? I am not even sure where to start? Thanks

257 is right. Here is a worked example that will work all of your stoichiometry problems.
http://www.jiskha.com/science/chemistry/stoichiometry.html