Question

A 1.00 g sample of naphthalene (C10H8) contains 0.562 g of hydrogen. What is the mass percent of carbon in the compound? 10.079%

Answer 1

C10H8 contains only C and H, so total mass minus mass H = mass C

1.00 g - 0.562 g = 0.438 g C

%C = [(0.438 g)/(1.00 g)]*100% = 43.8% C

NOTE: The actual %C in naphthalene is over 95% C. Your sample must have been impure.