Question 1 Report
An organic compound contains 72% carbon, 12% hydrogen and 16% oxygen by mass. What is the empirical formula of the compound?
[ H = 1.0. C = 12.0, O = 16.0 ]
The empirical formula of a compound is the simplest whole-number ratio of atoms in the compound. To find the empirical formula, we need to convert the percent composition by mass of each element to its corresponding number of moles, and then divide each number by the smallest number of moles to find the smallest whole-number ratio. Given the following percent composition by mass: - Carbon: 72% = 72 g / (12.0 g/mol) = 6.0 mol - Hydrogen: 12% = 12 g / (1.0 g/mol) = 12.0 mol - Oxygen: 16% = 16 g / (16.0 g/mol) = 1.0 mol Dividing each number of moles by the smallest number of moles (1.0 mol for oxygen), we get: - Carbon: 6.0 mol / 1.0 mol = 6.0 - Hydrogen: 12.0 mol / 1.0 mol = 12.0 - Oxygen: 1.0 mol / 1.0 mol = 1.0 Rounding each number to the nearest whole number, we get: - Carbon: 6.0 - Hydrogen: 12.0 - Oxygen: 1.0 The smallest whole-number ratio of atoms in the compound is C\(_6\)H\(_12\)O, which is the empirical formula of the compound.