C=12/46x100℅=1200/46=26,09
M(HCOOH) = 1 +12 +16+16+1 = 46
M(C) = 1*12 = 12
w = M(C) / M(HCOOH) = 12/46 = 0,26 (26%)
Mg⁺²Br₂⁻
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