1. What is Average Atomic Mass?

Definition: Average atomic mass is the weighted average of the atomic masses of all naturally occurring isotopes of an element.

Purpose: It helps chemists and physicists understand the composition of elements and perform accurate calculations in chemical reactions.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( A.M_{avg} \) — Average atomic mass (atomic mass units)
• \( m \) — Ratio term of isotope A
• \( a \) — Atomic mass of isotope A
• \( n \) — Ratio term of isotope B
• \( b \) — Atomic mass of isotope B

Explanation: The formula calculates a weighted average based on the relative abundance (ratio terms) of each isotope.

3. Importance of Average Atomic Mass

Details: The average atomic mass appears on the periodic table and is crucial for stoichiometric calculations in chemistry.

4. Using the Calculator

Tips: Enter the ratio terms (relative abundances) and atomic masses for both isotopes. The ratio terms don't need to sum to 100 - they represent relative proportions.

5. Frequently Asked Questions (FAQ)

Q1: What are atomic mass units (u)?
A: 1 atomic mass unit is defined as 1/12th the mass of a carbon-12 atom (approximately 1.6605 × 10⁻²⁷ kg).

Q2: How do I find isotope ratios?
A: Isotope ratios are typically determined through mass spectrometry and can be found in scientific literature.

Q3: Can I calculate for more than two isotopes?
A: Yes, simply extend the formula: (m×a + n×b + p×c + ...)/(m + n + p + ...).

Q4: Why is the average not just a simple mean?
A: Because different isotopes occur in different natural abundances, so we need a weighted average.

Q5: How precise should my inputs be?
A: Use as many decimal places as available, especially for the atomic masses which are known to high precision.