How many grams of nitrogen are needed to produce 460g of ammonia

1 mol N2 = 2 mol NH3

325g / 16g/mol = 20.3 mol which ammonia only requires 10.15 mol N2 to produce

10.15 mol x 28.014g/mol

= 284 g

it makes sense that the mass required should be smaller than the mass of the larger product molecules