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Butanedione, a component of butter and body odor, has a cheesy smell. Elemental analysis of butanedione gave the mass percent composition: C, 55.80%; H, 7.03%; O, 37.17%. The molar mass of butanedione is 86.09 g/mol. Determine the molecular formula of butanedione.

Respuesta :

joseaaronlara

Answer:

The answer to your question is       C₄H₆O₂

Explanation:

Data

C = 55.80%

H = 7.03 %

O = 37.17 %

Molar mass = 86.09 g/mol

Molecular formula = ?

Process

1.- Express the percents as grams

C = 55.80g

H = 7.03g

O = 37.17g

2.- Convert the grams to moles

Carbon

                                  12 g of C ---------------- 1 mol

                                  55.80 g  ---------------- x

                                  x = (55.80 x 1)/12

                                  x = 4.65 moles

Hydrogen

                                  1 g of H ------------------  1 mol

                                  7.03 g    ------------------  x

                                 x = 7.03 moles

Oxygen

                                  16 g of O --------------- 1 mol

                                   37.17 g   ----------------  x

                                   x = 2.32 moles

3.- Divide by the lowest number of moles

Carbon          4.65/2.32 = 2

Hydrogen      7.03/2.32 = 3

Oxygen          2.32/2.32 = 1

4.- Write the empirical formula

                          C₂H₃O

5.- Calculate the molar mass of the empirical formula

    C₂H₃O  = (12 x 2) + (3 x 1) + (16 x 1) = 24 + 3 + 16 = 43 g

6.- Divide the molar mass of butanedione by the molar mass of the empirical formula

                           86.09/43 = 2

7.- Multiply the empirical formula by two

                          C₄H₆O₂