A compound used in making nylon, is 43.8% oxygen. There are four oxygen atoms per molecule. What is the molecular weight of compound?

100 g compound contain 43.8 g oxygen; 1 8 oxygen present with $\frac{100}{43.8}\mathrm{g}$ g compound 16 x 4g or 4 mole oxygen present with $\frac{100}{43.8}\times 16\times 4=146\mathrm{g}$ compound
$\therefore$ mol. wt. of compound is 146.