**Empirical Formula**

The empirical formula is a representation of the simplest ratio of atoms of different elements present in a compound. It gives the relative number of atoms of each element in a compound, but does not provide the actual number of atoms.

**Determining the Empirical Formula**

To determine the empirical formula of a compound, one needs to know the mass or percentage composition of each element present in the compound. This information can be obtained through experimental data or from the molecular formula of the compound.

**Steps to Determine the Empirical Formula**

1. **Obtain the Mass or Percentage Composition:** The first step is to determine the mass or percentage composition of each element in the compound.

2. **Convert to Moles:** Convert the mass or percentage composition of each element to moles by dividing the given mass by the molar mass of the element.

3. **Determine the Ratio:** Determine the ratio of moles of each element by dividing the number of moles obtained for each element by the smallest number of moles calculated.

4. **Multiply by Whole Numbers:** Multiply the ratio obtained in the previous step by a whole number if necessary to obtain whole numbers. This step is usually required when the ratio obtained is not already a whole number.

5. **Write the Empirical Formula:** Write the empirical formula using the whole number ratio obtained in the previous step. The empirical formula should represent the simplest ratio of atoms of each element in the compound.

**Example:**

Let's consider a compound with the following mass composition:
Carbon (C) - 40%
Hydrogen (H) - 6.67%
Oxygen (O) - 53.33%

1. Convert the percentages to masses by assuming a 100g sample. This gives us:
Carbon (C) - 40g
Hydrogen (H) - 6.67g
Oxygen (O) - 53.33g

2. Convert the masses to moles using the molar mass of each element:
Carbon (C) - 40g / 12g/mol = 3.33 mol
Hydrogen (H) - 6.67g / 1g/mol = 6.67 mol
Oxygen (O) - 53.33g / 16g/mol = 3.33 mol

3. Determine the ratio of moles:
Carbon (C) - 3.33 mol
Hydrogen (H) - 6.67 mol / 3.33 mol = 2 mol
Oxygen (O) - 3.33 mol

4. Multiply by whole numbers (if necessary):
No multiplication is necessary in this case as the ratio is already a whole number.

5. Write the empirical formula:
The empirical formula for this compound is CH2O.

**Summary**

The empirical formula represents the simplest ratio of atoms of different elements in a compound. It can be determined by obtaining the mass or percentage composition of each element in the compound and converting it to moles. The ratio of moles is then determined, and if necessary, multiplied by whole numbers to obtain whole numbers. The empirical formula represents the simplest ratio of atoms of each element in the compound.