Problem: An unknown compound was determined to be 74.97% carbon, 8.39% hydrogen, and 16.64% oxygen. Calculate the empirical formula.

FREE Expert Solution

We’re being asked to determine the empirical formula of an unknown compound given the mass percent of C, H, and O.


Recall that the empirical formula is the simplest whole-number ratio formula of a compound


Step 1: Recall that mass percent is given by:


% mass=mass of Xtotal mass×100


The problem states that the compound is 74.97% C, 8.39 % H, and 16.64% O. Assuming we have 100 g of the compound, this means we have 74.97 g C, 8.39 H, and 16.64 g O.


Now, we need to get the moles of each element in the compound. 

The atomic masses are 12.01 g/mol C, 1.01 g/mol H, and 16.00 g/mol O.


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Problem Details

An unknown compound was determined to be 74.97% carbon, 8.39% hydrogen, and 16.64% oxygen. Calculate the empirical formula.