Question

надо найти молекулярную массу

Answer 1

М = 23*2+32*2+16*3= 158
W (Na) = M(Na)/M = 23*2 / 158 = 0.29 (29%)
W (s) = M(S)/M = 32*2/158 = 0.41 (41%)
W(O) = M(o)/M = 16*3/158 = 0.30  (30%)