Final answer:
The chemical formula for lead(IV) oxide is PbO2, as determined by the mole ratio of lead to oxygen which is 1:2, accounting for 32 g of oxygen reacting with 207 g of lead.
Step-by-step explanation:
The chemical formula for lead(IV) oxide is PbO2. This is derived from the information that 207 g of lead combines with oxygen to form 239 g of a lead oxide. Given the relative atomic masses (Pb = 207.2 u and O = 16.0 u), the compound formed must contain 32 g of oxygen because the mass of the lead oxide minus the mass of lead gives the mass of oxygen (239 g - 207 g = 32 g). Since 16 g is the molar mass of oxygen, 32 g corresponds to two oxygen atoms. Thus, we have one lead atom combining with two oxygen atoms, leading to the empirical formula PbO2.
This compound is also notably used in car batteries, where lead (IV) oxide participates in the chemical reaction with lead and sulfuric acid (H2SO4) to form lead sulfate (PbSO4) and water (H2O).