What is the mass (in g) of carbon in a sample of acetone, CH3COCH3, which also contains 2.45 g of hydrogen?

Answer is: the mass of the carbon is 14.57 grams.

m (H) = 2.45; mass of hydrogen in sample of acetone.

n (H) = m (H) : M (H).

n (H) = 2.45 g : 1.01 g/mol.

n (H) = 2.425 mol; amount of hydrogen.

From molecular formula of acetone: n (C) : n (H) = 3 : 6 (1 : 2).

n (C) = 2.425 mol : 2.

n (C) = 1.212 mol; amount of carbon in the sample.

m (C) = n (C) · M (C).

m (C) = 1.212 mol · 12.01 g/mol.

m (C) = 14.57 g.