Explicație:
Mg(OH)2 hidroxid de magneziu
MMg(OH)2=24+2×16+2×1=58
r.at.Mg:O:H=1:2:2
r.m. Ng:O:H=24:32:2=12:16:1
SO3 trioxid de sulf
MSO3=32+3×16=80
r.at. S:O=1:3
r.m S:O=32:48=2:3
H3PO3 acid fosforos
MH3PO3 =3×1+31+3×16=82
r.at. H:P:O = 3:1:3
r.m. H:P:O= 3:31:48
Na2O oxid de sodiu
MNa2O=2×23+16=62
r.at. Na:O=2:1
r.m. Na:O=46:16=23:8
Mg(NO3)2 azotat de magneziu
MMg(NO3)2=24+2×14+6×16=148
rrat.Mg:N:O=1:2:6
r.m.Mg::N;O=24:28:96=12:14:48
NNH4NO3 azotat de amoniu
MNH4NO3=2×14+4×1+3×16=76
r.at.N:H:N:O=1:4:1:3
r.m.N:H:N:O=14:4:14:48
H2S acid sulfhidric
MH2S=2×1+32=34
r.at.H:S=2:1
r.m.H:S=2:32=1:16
Na2CO3 carbonat de sodiu
MNa2CO3 =2×23+12+3×16=106
r.at.Na:C:O=2:1:3
r.m.Na:C:O=46:12:48=23:6:24
Al2SO4)3 sulfat de aluminiu
MMAl2(SO4)3=2×27+3×32+12×16=342
r.at.Al:S:O=2:3:12
r.m. Al:S:O=54:96:192
Ca3(PO4(2 fosfat de calciu
MCa3(PO4)2=3×40+2×31+8×16=310
r.at. Ca: P: O=3:2:8
r.m. Ca:P:O=120:62:128=110:31:64
