what is the empirical formula for a compound if a sample contains 3.72 g of p and 21.28 g of…

Explanation:

Step1: Calculate moles of P

Molar mass of P is approximately 30.97 g/mol. Moles of P = $\frac{3.72\ g}{30.97\ g/mol}\approx0.12\ mol$.

Step2: Calculate moles of Cl

Molar mass of Cl is approximately 35.45 g/mol. Moles of Cl = $\frac{21.28\ g}{35.45\ g/mol}\approx0.6\ mol$.

Step3: Find mole - ratio

Divide each number of moles by the smaller number of moles (0.12 mol). For P: $\frac{0.12\ mol}{0.12\ mol}=1$. For Cl: $\frac{0.6\ mol}{0.12\ mol}=5$.

Answer:

A. $PCl_{5}$