mass percent of carbon in pure ethanol is 52.1% a chemist analyzes an impure sample of ethanol and determines that the mass percent of carbon is 49.5% which of the following impurities could account for the low mass percent of carbon in the sample

(A) methanol, CH3OH
(B) acetone, C3H6O
(C) butanol, C4H9OH
(D) acetaldehyde,C2H4O

Question

mass percent of carbon in pure ethanol is 52.1% a chemist analyzes an impure sample of ethanol and determines that the mass percent of carbon is 49.5% which of the following impurities could account for the low mass percent of carbon in the sample

(A) methanol, CH3OH
(B) acetone, C3H6O
(C) butanol, C4H9OH
(D) acetaldehyde,C2H4O

justjm · Answer

Ethanol is C2H6O. If experimental mass % < theoretical mass %, then the mass ratio of the atom in interest is less in experimental source than theoretical.

Given this you can rule out D. Calculate the mass ratios and you'll get to the answer