1. What is Percentage Composition?

Percentage composition is the percentage by mass of each element in a compound. It shows the relative amount of each element present in the compound and is useful for determining empirical and molecular formulas.

2. How Does the Calculator Work?

The calculator uses the percentage composition formula:

Where:

• \( \text{atomic mass} \) — Atomic mass of the element (g/mol)
• \( n \) — Number of atoms of the element in the compound
• \( \text{MW} \) — Molecular weight of the compound (g/mol)

Explanation: The formula calculates what percent of the total molecular weight comes from a specific element in the compound.

3. Importance of Percentage Composition

Details: Percentage composition is crucial for determining empirical formulas, verifying molecular formulas, and understanding the relative amounts of elements in compounds. It's widely used in chemistry, material science, and pharmaceutical development.

4. Using the Calculator

Tips: Enter the atomic mass of the element in g/mol, the number of atoms of that element in the compound, and the total molecular weight of the compound in g/mol. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between percentage composition and mass fraction?
A: Percentage composition is mass fraction multiplied by 100. They represent the same relationship but in different formats.

Q2: Can I use this for ionic compounds?
A: Yes, the formula works for any chemical compound, whether covalent or ionic.

Q3: How accurate should my inputs be?
A: Use standard atomic masses from the periodic table (usually to 2 decimal places) for best results.

Q4: What if my percentage exceeds 100%?
A: This indicates an error in your inputs. Check that your molecular weight is correct and greater than the (atomic mass × n).

Q5: Can I calculate percentage composition for multiple elements?
A: Yes, but you need to perform the calculation separately for each element in the compound.