1. What is Exact Mass?

The exact mass of a molecule is the calculated mass derived from the most abundant isotopes of each element. It is calculated by summing the atomic masses of all atoms in the molecule, using the isotopic masses rather than the average atomic weights.

2. How Does the Calculator Work?

The calculator uses the exact mass formula:

Where:

• Atomic Mass — The mass of the most abundant isotope of each element (in daltons)
• Count — The number of atoms of each element in the molecule

Explanation: The calculator sums the product of each element's atomic mass and its count in the molecule.

3. Importance of Exact Mass

Details: Exact mass is crucial in mass spectrometry for identifying molecular formulas, distinguishing between compounds with similar nominal masses, and confirming molecular structures.

4. Using the Calculator

Tips: Enter elements and their counts in comma-separated format (e.g., "C6,H12,O6" or "C=6,H=12,O=6"). The calculator supports common elements with their most abundant isotopes.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between exact mass and molecular weight?
A: Exact mass uses isotopic masses of the most abundant isotopes, while molecular weight uses average atomic masses that account for all isotopes.

Q2: Why is exact mass important in mass spectrometry?
A: High-resolution mass spectrometers can measure masses precisely enough to distinguish between compounds with the same nominal mass but different exact masses.

Q3: How accurate is this calculator?
A: The calculator uses standard isotopic masses for common elements. For very precise work, consult more comprehensive tables.

Q4: What elements are supported?
A: The calculator supports common organic elements: H, C, N, O, F, P, S, Cl, Br, and I.

Q5: Can I use this for isotopic patterns?
A: This calculates only the monoisotopic mass. For isotopic distributions, more specialized tools are needed.