Question:

Reaction of a main group chloride (24.71g) with ammonia (10.9g) gave a mixture of products consisting of NH_{4}Cl (25.68g), a solid element A (2.57g) and a yellow crystalline nitride of this element (7.37g) according to the equation below

nA_{w}Cl_{x} + mNH_{3} ---> pNH_{4}Cl + qA + rA_{y}N_{z}

(where n, m, p, q, r, w, x, y, and z are coefficients to be determined).

I've tried solving this with simultaneous equations but i get 9 variables and 6 equations, so that can't work.

It should be done with equivalent weights but at the moment I am not really sure how. I think it has something to do with the chloride, since it has a valency of 1.