N2 + 3H2 ----> 2NH3
I MOLE NITROGEN ----> 2 MOLES OF AMMONIA
THEREFORE x MOLES OF NITROGEN -----> 12 MOLES OF AMMONIA
x = 12 * 1 / 2 = 6
6 moles of nitrogen.
You need to start from the following balanced chemical reaction, such that:
`N_2 + 3H_2 -> 2NH_3`
Hence, with 1 mol of nitrogen `N_2` you can obtain 2 moles of ammonia `NH_3` , thus, you may evaluate the unknown number of moles of `N_2` required to produce 12 moles of `NH_2` , using the law of proportions, such that:
`x_(N_2) = 12/2 => x_(N_2) = 6` moles
Hence, evaluating the number of moles of `N_2` required to produce 12 moles of `NH_2` ,yields `x_(N_2) =` 6 moles.