A compound is composed of 56.4% phosphorus and the remainder oxygen. Determine the empirical formula of the compound.

Question

Quizplus · Accepted Answer

To find the empirical formula, we calculate the moles of each element in 100g of the compound. For phosphorus (P), with an atomic mass of approximately 31 g/mol, we have $56.4 \, \text{g} \div 31 \, \text{g/mol} = 1.82 \, \text{mol}$. For oxygen (O), with an atomic mass of 16 g/mol, the remainder is $100\% - 56.4\% = 43.6\%$, so $43.6 \, \text{g} \div 16 \, \text{g/mol} = 2.725 \, \text{mol}$. The ratio of P to O is approximately 1:1.5, which simplifies to 2:3 when both are divided by the smaller number. Therefore, the empirical formula is $P_2O_3$, which corresponds to choice D.

A Compound Is Composed of 56