A 0.600 g sample of a compound of arsenic and oxygen was found to contain 0.454 g of arsenic. What is the empirical formula of the compound

Question

Quizplus · Accepted Answer

To find the empirical formula, we need to determine the mole ratio of arsenic to oxygen.

First, we need to convert the mass of arsenic and oxygen to moles:
Moles of As = 0.454 g / 74.92 g/mol = 0.00607 mol
Moles of O = (0.600 g - 0.454 g) / 16.00 g/mol = 0.00966 mol

Next, we need to divide both mole values by the smallest mole value to get the mole ratio:
As:O = 0.00607 mol / 0.00607 mol = 1 : 1.59 or approximately 1:1.5

The empirical formula should have the smallest whole number ratio of atoms, so we can multiply both subscripts by 2 to get whole numbers:
As2O3

Therefore, the empirical formula of the compound is As2O3, which is represented by choice D.

A 0600 G Sample of a Compound of Arsenic and Oxygen