Chemistry Homework Help?

Complete combustion of 5.30g of a hydrocarbon produced 16.9g of CO2 and 6.06g of H2O. What is the empirical formula for the hydrocarbon? Insert subscripts as necessary.

The answer I got was C3H5 but it keeps telling me I am incorrect. 

1 Answer

Relevance
  • 3 weeks ago
    Favorite Answer

    Empirical formula....

    CxHy + O2 --> CO2 + H2O ............... not balanced

    5.30g ............. 16.9g...6.06g

    16.9g CO2 x (1 mol CO2 / 44.0g CO2) x (1 mol C / 1 mol CO2) = 0.384 mol C

    6.06g H2O x (1 mol H2O / 18.0g H2O) x (2 mol H / 1 mol H2O) = 0.337 mol H

    0.384 mol C / 0.337 = 1.14 mol C

    0.337 mol H / 0.337 = 1.00 mol H

    Either the numbers are very sloppy and the empirical formula is CH, or we need to multiply the moles by 7 to get whole numbers.

    1.14 x 7 = 7.98 ~ 8 mol C

    1.00 x 7 = 7 mol H

    empirical formula = C8H7

Still have questions? Get your answers by asking now.