1. What is an Empirical Formula?

The empirical formula of a compound represents the simplest whole number ratio of atoms of each element present in the compound. It doesn't show the actual number of atoms like a molecular formula, but rather the simplest ratio between them.

2. How to Calculate Empirical Formula

The calculation involves these steps:

Process:

1. Convert mass or percentage of each element to moles
2. Divide each mole value by the smallest number of moles
3. Multiply by an integer to get whole numbers if needed
4. Write the formula using these whole number ratios

3. Step-by-Step Calculation

Example: For a compound with 40% carbon, 6.7% hydrogen, and 53.3% oxygen:

• Assume 100g sample: 40g C, 6.7g H, 53.3g O
• Convert to moles: 40/12 = 3.33 mol C, 6.7/1 = 6.7 mol H, 53.3/16 = 3.33 mol O
• Divide by smallest (3.33): C=1, H=2, O=1
• Empirical formula: CH₂O

4. Using the Calculator

Instructions: Enter each element and its corresponding moles separated by commas, with different elements separated by semicolons. For example: "C,1.33;H,4;O,1".

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between empirical and molecular formula?
A: Empirical shows simplest ratio, molecular shows actual atom counts (e.g., CH₂O vs C₆H₁₂O₆ for glucose).

Q2: What if the mole ratios aren't whole numbers?
A: Multiply all ratios by an integer to convert to whole numbers (e.g., 1:1.5 becomes 2:3 when multiplied by 2).

Q3: How accurate is this calculator?
A: It provides exact ratios based on input values, but real-world data may require rounding experimental measurements.

Q4: Can I use percentage composition?
A: Yes, but first convert percentages to moles by assuming 100g total mass and dividing by atomic weights.

Q5: What about hydrates or complex compounds?
A: The same principle applies - calculate mole ratios of all elements including water molecules in hydrates.