1) SO₂ = 32 + 16*2=64
N₂O₅ = 14*2 + 16*5 = 108
H₂SiO₃ = 1*2 + 28 + 16*3 = 78
Na₂SO₃ = 23*2 + 32 + 16*3 = 126
Al(OH)₃ = 27 + 16*3 + 1*3 = 78
2) NO₂ = 14 + 16*2 = 46
P₂O₅ = 31*2 + 16*5 = 142
H₂CO₃ = 1*2 + 12 + 16*3 = 62
K₂SO₄ = 39*2 + 32 + 16*4 = 174
Cr(OH)₃ = 52 + 16*3 + 1*3 = 103