Molecular Formula

[806127942]

Similar to a problem on our midterm 1, how do you find the molecular formula if you aren't given the molecular weight ? If the empircal formula and molecular formula are the same for salicylic acid and the mass % is given, how do you find molecular formula after getting the empirical? There is no molecular weight given to divide by.

[006455961]

If the molecular formula is the same as the empirical formula, the key is recognizing that the empirical formula already represents the true molecular formula. To solve, start by determining the empirical formula using the given mass percentages of each element. Assume 100 grams of the compound, convert the percentages to moles for each element, and then find the simplest whole-number ratio of moles to get the empirical formula.

Since the problem states that the empirical formula is the same as the molecular formula, you do not need the molecular weight to proceed further. The molecular formula is identical to the empirical formula. For example, salicylic acid’s molecular formula is C7H6O3, which matches its empirical formula because the subscripts cannot be simplified further. Without molecular weight, no additional steps are required if the equivalence is explicitly stated.