Which element has a mass percent composition of 54.50% in vitamin c, c6h8o6?

Vitamin C has the formula C₆H₈O₆, it means there are 6 carbon, 8 hydrogen and 8 oxygen.
to find the mass percent composition of each element, we will divide the mass of element in the compound by total molar mass of the compound and then multiply it with 100..
Now, the molar mass of vitamin c =176.12g/mol
Molar mass of carbon in the compound = 12 x 6 =72
mass percent composition of carbon = 72/ 176.12 x100 = 0.4088 x 100 = 40.88%
Molar mass of hydrogen in the compound = 1.008 x 8 = 8.064
mass percent composition of hydrogen = 8.064/176.12 x 100 = 0.0458 x 100 = 4.58%
Molar mass of oxygen in the compound = 16 x 6 = 96
mass percent composition of oxygen = 96/176.12 x 100 = 0.5450 x 100 = 54.50%
Thus, the element is Oxygen which has a mass percent composition of 54.50% in vitamin C.

Yes she is correct. the answer is completely correct