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A compound has an empirical formula of C₂H₂0 and a molecular weight of 126.11 g/mol. What is the molecular formula?

a. CH₂O
b. C₂H₄O₂
c. C₃H₆O₃
d. C₄H₈O₄

User Yokoloko
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1 Answer

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Final answer:

The molecular formula of the given compound is C4H8O4 which is determined by calculating the ratio of the molecular weight to the weight of the empirical formula, C2H2O, and then multiplying the empirical formula by this ratio.

Step-by-step explanation:

The molecular formula of a compound is determined by the empirical formula and the molar mass of the compound. In this case, the compound has an empirical formula of C₂H₂O and a molar mass of 126.11 g/mol. The molar mass of the empirical formula (C₂H₂O) is approximately 44.05 g/mol (12.01 for each carbon, 1.008 for each hydrogen, and 16.00 for the oxygen). To find the relationship between the empirical and molecular formulas, we divide the molar mass of the compound by the molar mass of the empirical formula:

(126.11 g/mol) / (44.05 g/mol) ≈ 2.86. This number is closest to 3, suggesting that the molecular formula contains three times as many atoms as the empirical formula. Therefore, by multiplying the empirical formula by the ratio factor (approximately 3), we obtain the molecular formula: 3 * C₂H₂O = C₆H₆O₃.

However, none of the answer choices exactly match C₆H₆O₃. Let's reevaluate the options given. If we consider the answer options, the empirical formula of C₂H₄O₂ is indeed a multiple of C₂H₂O, and when we take into account the empirical formula's molar mass (60.05 g/mol), we can calculate the multiple:

(126.11 g/mol) / (60.05 g/mol) = 2.1. Since this is approximately equal to 2, the molecular formula is 2 * C₂H₄O₂ = C₄H₈O₄. Therefore, the correct molecular formula of the compound is C₄H₈O₄, which corresponds to option d.

User RisingSun
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