Có 2M + X2 = 2MX
2,06/(M+X) 4,12/(M+X) mol
2Al + 3X2 = 2AlX3
5,34/(27+3X) 3,56/(27+3X) mol
2M + S = M2S 1,56/(M+16)
1,56/(2M+32) mol
Co 4,12/(M+X) = 1,56/(M+16) va 2,06/(M+X)= 5,34/(27+3X)
⇔ 2,56M – 1,56X= -65,92 va 5,34M – 0,84X =55,62
⇔M=23, X=80 M la Na, X la Br