1. The problem statement, all variables and given/known data One liter of nitrogen combines with 3 L of hydrogen to form 2 L of ammonia. If the molecules of nitrogen and hydrogen have two atoms each, how many atoms of hydrogen and nitrogen are in one molecule of ammonia? 2. Relevant equations Chemical equations 3. The attempt at a solution I didn't know where to start so I looked at the solution key and got this: The number of liters tells us how many molecules of the original combine to form this number of molecules of the product. Using these numbers as multipliers in a chemical equation gives us 1N2 + 3H2 → 1Nx Hy Making sure that we have the same number of atoms of each kind on each side, we get x = 1 and y = 3. Can somebody explain to me what the hell just happened?