Ответ:

дано

W(C) = 42.86%

W(O) = 57.14%

M(CxOy) = 28 g/mol

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CxOy - ?

W(C) = 42.86%   m(C) = 42,86 g   M(C) = 12 g/mol

W(O) = 57.14%  m(O) = 57.14 g  M(O) = 16 g/mol

n(C) = m/M = 42.86 / 12 = 3.6 mol

n(O) = m/M = 57.14 / 16 =  3.6 mol

n(C) : n(O) = 3.6 : 3.6 = 1 :1 ==> CO

  M(CO) = 28 g/mol

ответ : СО

Объяснение: