Titanium dioxide and zinc oxide are two of the 16 active ingredients approved by the FDA for use in sunscreens. Which compound contains a higher percentage of oxygen by mass

The compound with the higher percentage of oxygen by mass is titanium dioxide.

Titanium dioxide, TiO2, has a molar mass of 79.866 g/mol and O2 has a molar mass of 32.

Percentage by weight of oxygen in TiO2 = 32/79.866 x 100

                                                          = 40.07%

Zinc oxide, ZnO, has a molar mass of 81.38 g/mol

percentage by weight of oxygen in ZnO = 16/81.38 x 100

                                                               = 19.66%

Thus, titanium dioxide has a higher percentage by weight of oxygen than zinc oxide.

More on percentage by mass of substances can be found here: link

has higher percentage of oxygen by mass.

Explanation:

To calculate the mass percent of element in a given compound, we use the formula:

1. Mass of oxygen in =

2. Mass of oxygen in =

Thus has higher percentage of oxygen by mass.