How do we find the molar mass of a gas produced?

Example

if 1.00 kg of N2H2 reacts with 1.00kg of H202. How many moles of N2 could be formed?

THe equation is N2H2+2H202 > N2 + 4H20

This is a limiting reagent problem. How do I know that? Because amounts are given for BOTH reactants.

I work these the long way.
First, convert 1000 g N2H2 to mols. mols = grams/molar mass.
Convert 1000 g H2O2 to mols. Same way.
Using the coefficients in the balanced equation, convert mols N2H2 to mols N2.
Same process convert mols H2O2 to mols N2. Both answers for mols N2 can't be right; the correct answer in limiting reagent problems is ALWAYS the smaller one and the reagent producing that number is the limiting reagent.
Post your work if you get stuck.