Write The Empirical Formula for The Following Compounds Calculator

What is an Empirical Formula?

The empirical formula of a compound shows the simplest whole number ratio of atoms of each element present in the compound. It's derived from the mass percentages of each element in the compound.

For example, if a compound contains 75% carbon and 25% hydrogen by mass, its empirical formula would be CH₃ (methane).

How to Calculate the Empirical Formula

The process involves these steps:

1. Determine the mass percentage of each element in the compound
2. Convert mass percentages to grams (assuming 100g total)
3. Convert grams to moles using molar masses
4. Divide each mole value by the smallest number of moles
5. Round to the nearest whole numbers to get the empirical formula

Examples of Empirical Formula Calculations

Let's look at two examples to understand how the empirical formula is calculated.

Example 1: Carbon and Hydrogen

A compound contains 75% carbon and 25% hydrogen by mass. Here's how to calculate its empirical formula:

1. Assume 100g of compound: 75g C and 25g H
2. Convert to moles: 75g C ÷ 12.01 g/mol = 6.25 mol C; 25g H ÷ 1.01 g/mol ≈ 24.75 mol H
3. Divide by smallest moles (6.25): C = 1, H ≈ 4
4. Empirical formula: CH₄ (methane)

Example 2: Nitrogen and Oxygen

A compound contains 14% nitrogen and 86% oxygen by mass. Here's the calculation:

1. Assume 100g of compound: 14g N and 86g O
2. Convert to moles: 14g N ÷ 14.01 g/mol ≈ 1.00 mol N; 86g O ÷ 16.00 g/mol ≈ 5.38 mol O
3. Divide by smallest moles (1.00): N = 1, O ≈ 5.38
4. Round to whole numbers: N = 1, O = 5
5. Empirical formula: NO₅