Chapter 2 Atoms, Molecules, and Ions - 2-10 Chemical Analysis: Determining Compound Formulas - Case Study - Questions - Page 90: 1

$AsCu_3S_4$

From a sample of 100.0 g: As: 19.024 g, 74.922 g/mol --> 0.25392 mols Cu: 48.407 g, 63.546 g/mol --> 0.76176 mols S: 32.569 g, 32.06g/mol --> 1.0159 mols Normalizing by the number of mols of As: As: 0.25392 /0.25392 = 1.0 Cu: 0.76176/0.25392 = 3.0 S: 1.0159/0.25392 = 4.0 Therefore the empirical formula is: $AsCu_3S_4$