дано
W(C) = 40%
W(H) = 6.7%
M(CxHyOz) = 60 g/mol
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CxHyOz-?
W(O) = 100%-(W(C)+W(H)) = 100 - (40+6.7) = 53.3%
C:H:O = 40 / 12 : 6.7 / 1 : 53.3 / 16 = 33.3 : 6.7 : 33.3 = 1 :2 :1
CH2O
M(CH2O) = 30 g/mol
n = M(CxHyOz) / M(CH2O) = 60 /30 = 2 раза
M(CxHyOz) = n*M(CH2O)
M(C2H4O2)
CH3-COOH
ответ CH3COOH