What is the empirical formula for a sample of a compound that contains 259.2gF and 40.8gC?

To determine the empirical formula, first convert the masses of fluorine (F) and carbon (C) to moles. The molar mass of F is approximately 19 g/mol, and for C, it is about 12 g/mol. Calculating the moles: for F, ( \frac{259.2 , \text{g}}{19 , \text{g/mol}} \approx 13.63 , \text{mol} ); for C, ( \frac{40.8 , \text{g}}{12 , \text{g/mol}} \approx 3.4 , \text{mol} ). Dividing by the smaller number of moles (3.4) gives a ratio of approximately 4:1 for F:C, leading to the empirical formula of ( \text{C}_1\text{F}_4 ) or simply ( \text{CF}_4 ).