Valproic acid, used to treat seizures and bipolar disorder, is composed of C, H, and O. A 0.165-g sample is combusted in a combustion apparatus. The gain in mass of the H2O absorber is 0.166 g, whereas that of the CO2 absorber is 0.403 g. What empirical formula for valproic acid do these results indicate?

Question

Chemistry

Alicia Jenkins

10 May, 19:09

Valproic acid, used to treat seizures and bipolar disorder, is composed of C, H, and O. A 0.165-g sample is combusted in a combustion apparatus. The gain in mass of the H2O absorber is 0.166 g, whereas that of the CO2 absorber is 0.403 g. What empirical formula for valproic acid do these results indicate?

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Answers (1)

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Madilynn Foley · Answer 1

C4H8O1.

Explanation:

The amount of carbon in the sample comes from the 0.403 g of CO2.

This = (12 / 44) * 0.403 = 0.1099 g C.

The amount of hydrogen is (2.016 / (16+2.016) * 0.166 = 0.01858 g H.

Thus the mass of oxygen in the valproic acid = 0.165 - 0.1099 - 0.011858

= 0.03652 g O.

Dividing by the relative atomic masses of the 3 elements the ratio of C : H : O is

0.00916 : 0.01843 : 0.002285

= 4 : 8 : 1.

So the empirical formula is C4H8O1.