To determine the empirical formula of the substance, we need to find the ratio of the number of atoms of each element in the compound. Here are the steps to calculate the empirical formula:
Step 1: Find the number of moles of each element.
Number of moles of carbon (C) = mass of C / molar mass of C
Number of moles of hydrogen (H) = mass of H / molar mass of H
Number of moles of oxygen (O) = mass of O / molar mass of O
The molar masses of the elements are approximately:
Molar mass of C ≈ 12.01 g/mol
Molar mass of H ≈ 1.01 g/mol
Molar mass of O ≈ 16.00 g/mol
Step 2: Find the simplest ratio of the moles of each element.
Divide the number of moles of each element by the smallest number of moles calculated in Step 1.
Step 3: Write the empirical formula using the whole-number ratios from Step 2.
Let's calculate it:
Step 1:
Number of moles of C = 5.28 g / 12.01 g/mol ≈ 0.4396 mol
Number of moles of H = 0.887 g / 1.01 g/mol ≈ 0.8782 mol
Number of moles of O = 3.52 g / 16.00 g/mol ≈ 0.2200 mol
Step 2:
The smallest number of moles is approximately 0.2200 mol (oxygen).
Divide the moles of each element by 0.2200 mol:
Carbon: 0.4396 mol / 0.2200 mol ≈ 2
Hydrogen: 0.8782 mol / 0.2200 mol ≈ 4
Oxygen: 0.2200 mol / 0.2200 mol = 1
Step 3:
The empirical formula is written as C2H4O.