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The analysis of a compound gives the following percent composition by mass: C - 61.38%, H - 11.33%, S - 10.93%, O - 16.36%. Given the molar mass is 293.5 g, what is its molecular formula?

User BrumScouse
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Final answer:

To find the molecular formula of the compound, we calculate the moles of each element using their assumed masses from a 100 g sample and then determine the empirical formula. Using the molar mass, we find the multiplier to convert the empirical formula to the molecular formula.

Step-by-step explanation:

To determine the molecular formula of a compound with the given percent composition by mass (C - 61.38%, H - 11.33%, S - 10.93%, O - 16.36%) and the molar mass of 293.5 g, we first need to find the empirical formula and then use the molar mass to deduce the molecular formula.

We assume a 100 g sample to make calculations straightforward, which gives us the following masses for each element: 61.38 g of C, 11.33 g of H, 10.93 g of S, and 16.36 g of O. The moles of each element can be calculated by dividing each mass by the respective atomic weight: C (12.01 g/mol), H (1.008 g/mol), S (32.06 g/mol), and O (16.00 g/mol).

Divide the number of moles of each element by the smallest number to find the ratio of the elements in the empirical formula. Next, multiply the empirical formula by a whole number to get the molecular formula, such that the mass of the empirical formula times this number equals the given molar mass (293.5 g).

User Mina Samir
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