College Chemistry 1

Question

A sample of trifluoroacetic acid, C2HF3O2, contains  80.5 g of fluorine. Calculate the mass of the trifluoroacetic acid sample.

Answer 1

The is the mass percentage type of calculation: wt. % = part over whole X 100

1 mole C₂HF₃O₂ = 2 x 12.0 + 1.0 + 3 x 19.0 + 2 x 16.0 = 114.0 g

F % = 57 / 114.0 x 100 = 50 % (both numbers in molar mass)

Use the formula:

80.5 g / 50 % = 161.0 g of trifluoroacetic acid