Aspirin is a compound with the molecular formula C9H89O4. what is it's percentage composition?

Answer 1

For starters, the molecular formula is C₉H₈O₄, not what you have shown.

To find the % composition of a compound, you first determine the molecular weight (or molar mass) of the compound, then divide the molecular mass (molar mass) of each element in the compound times the number of atoms in the compound by the total mass and, to convert to a %, multiply by 100.

For aspirin the molecular weight = 164 amu. The % of the C will be [(9 x 12 amu) / 164 amu] x 100 = 65.85 or approx 66%.

Do the H & O in the same way.