A compound contains 28 percent of nitrogen and 72 percent of a metal by weight. It is known that 3 a

Question

A compound contains 28 percent of nitrogen and 72 percent of a metal by weight. It is known that 3 atoms of the metal combine with 2 atoms of N. Find the atomic weight of the metal.

Professor PC Thomas Classes · Answer

The formula of the compound is $	ext{M}_3	ext{N}_2$. The mass ratio of Metal to Nitrogen is $3(A_M) : 2(14) = 72 : 28$. Solving the proportion: $\frac{3 A_M}{28} = \frac{72}{28} \implies 3 A_M = 72 \implies A_M = 24$ (The metal is Magnesium).