Answer to Question #325123 in Organic Chemistry for Joss

Question

Arsenic and oxygen react together to form arsenic oxide.  A sample of arsenic contains 0.4774 g, and a sample of oxygen contains 0.2043 g.  What is the formula of the arsenic oxide formed?

Answer 1

Solution:

The molar mass of arsenic (As) is 74.922 g/mol

The molar mass of oxygen (O) is 15.999 g/mol

Calculate the moles of each element in the oxide:

Moles of As = (0.4774 g As) × (1 mol As / 74.922 g As) = 0.00637 mol As

Moles of O = (0.2043 g O) × (1 mol O / 15.999 mol O) = 0.01277 mol O

Divide both moles by the smallest of the results:

As: 0.00637 mol / 0.00637 mol = 1

O: 0.01277 mol / 0.00637 mol = 2

Therefore, the empirical formula of the arsenic oxide is AsO₂ (or As₂O₄)

Arsenic dioxide = As₂O₄

Answer: The formula of the arsenic oxide is AsO₂ (or As₂O₄)