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I think the steps to finding the empirical formula and molecular formula are the same. You would need the empirical formula to find the molecular formula. You would have to divide the gram molecular mass by the empirical formula mass. Then, multiply each of the subscripts within the empirical formula by the previous quotient.
I think it is easier to learn it as one process, either you can find the molecular formula using the empirical or the other way around. Finding the molecular formula first seems like a shorter process to me. First you multiply the given total mass by the percents of composition given, the mass you get from this you convert to moles using the atom weight. Using these mole values you can write out the molecular formula, then simply it to the empirical formula. Hope this helps, if it doesn't really make sense there is a good khan academy video on this.
To find the empirical formula you first have to find the mass composition of each element, then find the moles of each element, and divide the moles of each element by the element with the smallest number of moles. If needed, round these values found to the nearest whole number to get the molar ratios. Then, to find the molecular formula find the molar mass of your empirical formula and divide that value by the molar mass of the entire compound (this should be given in the question). This will give you another ratio that will tell you whether you need to multiple the subscript of your empirical formula to find the molecular formula.
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