In the problem, we are tasked to solved for the amount of carbon (C) in the acetone having a molecular formula of C 3 H 6 O. We need to find first the molecular weight if Carbon (C), Hydrogen (H), Oxygen (O).
Molecular Weight: C=12 g/mol H=1 g/mol O=16 g/mol
To calculate for the percent by mass of acetone, we assume 1 mol of acetone. %C= %C=62.07% Therefore, the percent by mass of carbon in acetone is 62.07%