2025 Chemistry Nomenclature Practice Test – Complete Exam Prep

Tetraphosphorus decoxide is a molecular compound that consists of phosphorus and oxygen atoms. The name "tetraphosphorus" indicates there are four phosphorus atoms present, and "decoxide" signifies there are ten oxygen atoms. The prefix "tetra-" correlates with the number four for phosphorus, while "deca-" refers to the number ten for the oxygen atoms.

To derive the chemical formula, we recognize that tetraphosphorus decoxide is composed of four phosphorus atoms and ten oxygen atoms, which translates to the formula P4O10. This nomenclature aligns with the rules for naming molecular compounds, where prefixes denote the specific number of each type of atom in the formula.

In contrast, other choices do not reflect the correct number of phosphorus and oxygen atoms based on the specified prefixes in the name. For instance, P2O5 contains too few phosphorus atoms, while P4O8 and P2O10 do not accurately reflect the quantities indicated by the prefixes. Thus, the correct representation of tetraphosphorus decoxide is indeed P4O10.