A compound of oxygen and nitrogen has the composition 1.52 g N and 3.47 g of oxygen. The molar mass of this compound is known to be between 90 and 95 g. Determine the molecular formula and molecular mass of compound.

PLACEHOLDER ANSWER - the answer is a formula and a mass. Nitrogen is $$\frac{1.52}{14} \approx 0.109$$ mol and oxygen is $$\frac{3.47}{16} \approx 0.217$$ mol, a ratio of $$1 \colon 2$$, so the empirical formula is $$\text{NO}_2$$ with mass 46. A molar mass between 90 and 95 means two such units, so the molecular formula is $$\text{N}_2\text{O}_4$$ and the molecular mass is 92.