Final answer:
The molecular formula of a compound with the empirical formula NO2 and a molecular mass of 92 g/mol is N2O4, which is determined by calculating how many empirical formula units fit into the molecular mass.
Step-by-step explanation:
To find the molecular formula of a compound from its empirical formula and its given molar mass, we should first calculate the molar mass of the empirical formula.
Then, we compare this to the actual molar mass of the compound.
If the empirical formula of a compound is NO2 with a molar mass of 46.0055 g/mol (14.0067 for N and 16.00 for O each), and the given molecular mass is 92 g/mol, we can determine how many times the empirical formula mass fits into the molecular mass.
Dividing the molecular mass by the empirical formula mass, we get:
92 g/mol ÷ 46.0055 g/mol = 2.
Therefore, the molecular formula contains two empirical formula units.
Hence, the molecular formula is N2O4, or simply expressed as N2O4.