What is the percent by mass of carbon in acetone (C3H6O)?

• A. 40.0%
• B. 20.7%
• C. 62.1%
• D. 50.0%

Answer: (C)

Verified step by step guidance

1. Identify the molecular formula of acetone, which is C\_3H\_6O, meaning it contains 3 carbon atoms, 6 hydrogen atoms, and 1 oxygen atom.
2. Calculate the molar mass of each element in acetone using their atomic masses: Carbon (C) = 12.01 g/mol, Hydrogen (H) = 1.008 g/mol, Oxygen (O) = 16.00 g/mol.
3. Find the total molar mass of acetone by multiplying the number of atoms of each element by their atomic masses and summing them up: \(\text{Molar mass} = (3 \times 12.01) + (6 \times 1.008) + (1 \times 16.00)\).
4. Calculate the total mass of carbon in one mole of acetone by multiplying the number of carbon atoms by the atomic mass of carbon: \(\text{Mass of C} = 3 \times 12.01\) g.
5. Determine the percent by mass of carbon in acetone using the formula: \(\% \text{C} = \left( \frac{\text{Mass of C}}{\text{Molar mass of acetone}} \right) \times 100\%\).