Final answer:
The student's question revolves around the mass percent composition of ibuprofen, a compound with molecular formula C13H18O2, for which the molecular mass would be calculated by multiplying the atomic masses of carbon, hydrogen, and oxygen by the number of atoms of each present in the formula and adding these together.
Step-by-step explanation:
The student is asking about the mass percent composition of ibuprofen, which is a covalent compound with the molecular formula C13H18O2. The percentages given are 75.69% carbon (C), 8.80% hydrogen (H), and 15.51% oxygen (O). Computing the molecular mass, or molecular weight, of ibuprofen involves multiplying the number of atoms of each element in the formula by the atomic mass of that element, and then summing these values.
To calculate the molecular mass of ibuprofen, we would use the formula:
Molecular mass of C13H18O2 = (13 × atomic mass of C) + (18 × atomic mass of H) + (2 × atomic mass of O)
After substituting the atomic masses (carbon: approximately 12.01 amu, hydrogen: approximately 1.01 amu, and oxygen: approximately 16.00 amu), we calculate the molecular mass, which is useful in many chemical calculations including finding the percent composition of ibuprofen.
The molecular mass of ibuprofen, C13H1802, can be calculated by summing up the atomic masses of all the atoms in the compound. Using the periodic table, the atomic masses are: C=12.01 amu, H=1.01 amu, and O=16.00 amu. The molecular mass of ibuprofen is therefore (13x12.01) + (18x1.01) + (2x16.00) = 206.29 amu.