A sample of trifluoroacetic acid, C2HF3O2, contains 49.3 g of oxygen. Calculate the mass of the trifluoroacetic acid sample.

Answer 1

Note that each mole of TFA (trifluoroacetic acid) contains 2 moles of O. So, we will find the moles of O present, and then convert that to moles of TFA and then convert moles TFA to grams TFA using a molar mass of 114 g/mol.

49.3 g O x 1 mol O/16 g = 3.08 mols O present

3.08 mols O x 1 mol TFA / 2 mols O = 1.54 mols TFA present

1.54 mols TFA x 114 g / mol = 176 g TFA present