Percentage composition: Ammonia `(NH_(3))` si a pungent smelling very soluble gas, given an alkatline solution containing ammonnium hydoximate. It is used as a refigerment and for the manufacture fo fertilizers. Calculate the mass percentage fo the elements in ammnia.
Strategy: We need the mass of an element in a given mass of compound. To get this information, we interpect the formula in molar terms and then convert moles to masses. Every molecule of ammonia always has the formula `NH_(3),i.e., 1` mol of `NH_(3)` always contains 1 mol of `N` atoms and 3 mol of `H` atoms.

Explanation

Using Ew.(1.12) we have,
Mass % of `N` in `NH_(3) = ("Mass of N in mol of" NH_(3))/("Mass of 1 mol of" NH_(3)) xx 100%`
`= (14.0g N)/(17.0g NH_(3)) xx100% = 82.4%`
i.e., `82.4g N` per `100.0g NH_(3)`.
Mass % of `H` in `NH_(3) = ("Mass of H In mol of" NH_(3))/("Mass of 1 mol of" NH_(3)) xx100%`
`= (3.00g H)/(17.0g NH_(3)) xx100% = 17.6%`
i.e., `17.6g H` per `100g NH_(3)`.