Question

The average relative mass of an ozone molecule is 48.0 u. An ozone molecule contains only oxygen atoms. What does this molecular weight indicate about the formula of the ozone molecule?

a. It is monoatomic.
b. It is diatomic.
c. It is triatomic.
d. The data tells nothing about the formula of an ozone molecule.

Answer 1

The average relative mass of an ozone molecule being 48.0 u indicates that ozone is a triatomic molecule (O3), as each oxygen atom has an atomic mass of approximately 16 u.

Step-by-step explanation:

The average relative mass of an ozone molecule is 48.0 u and since it contains only oxygen atoms, we can deduce its molecular formula. The atomic mass of oxygen is approximately 16 u. Therefore, the molecular weight of ozone (48.0 u) suggests that there must be three oxygen atoms present, as 16 u × 3 = 48 u. This makes the ozone molecule triatomic.

Thus, the formula of the ozone molecule is O3 because the molecular weight of ozone corresponds to the combined atomic weights of three oxygen atoms. This answers the student's question, indicating that the relative molecular weight suggests that ozone is triatomic, which corresponds to option c.