The empirical formula CH₂O has a total molar mass of:
1 carbon atom (12.01 g/mol) + 2 hydrogen atoms (1.01 g/mol x 2) + 1 oxygen atom (16.00 g/mol) = 30.03 g/mol
To find the molecular formula, we need to know how many times this molar mass goes into the given molar mass of 90.0 g/mol:
90.0 g/mol ÷ 30.03 g/mol = 2.998...
This is very close to 3, so we can assume that the molecular formula is three times the empirical formula:
(C₁H₂O₁) x 3 = C₃H₆O₃
Therefore, the molecular formula of this acid is C₃H₆O₃.
The empirical formula of a certain acid is CH₂O. Whatis the molecular formula, if the molar mass is 90.0 g/mol?
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