Adipic acid contains 49.32% C, 43.84% O, and 6.85% H by mass. What is the empirical formula?

Question

Quizplus · Accepted Answer

To find the empirical formula, we assume a 100 g sample, which gives us 49.32 g of C, 43.84 g of O, and 6.85 g of H. The molar mass of C is 12.01 g/mol, O is 16.00 g/mol, and H is 1.01 g/mol. Dividing the mass of each element by its molar mass gives us the moles of each element: C = 49.32 g / 12.01 g/mol = 4.11 mol, O = 43.84 g / 16.00 g/mol = 2.74 mol, H = 6.85 g / 1.01 g/mol = 6.78 mol. The smallest number of moles is for oxygen, so we divide all mole values by 2.74 to simplify the ratio to the smallest whole numbers: C = 1.5, O = 1, H = 2.48. Since we can't have half atoms, we multiply all by 2 to get whole numbers, resulting in C3H5O2, which matches choice B.

Adipic Acid Contains 49