# What is the percent by mass of carbon in acetone, C_3H_6O?

"Mass of carbon"/"Mass of acetone"xx100% $=$ $\text{Percentage by mass Carbon}$.
We take the formula mass of acetone, $58.08 \cdot g \cdot m o {l}^{-} 1$, and perform the calculation,
(3xx12.011*g*mol^-1)/(58.08*g*mol^-1)xx100% $\cong$ 60%