Exact Mass Calculator Molecular Formula

Exact Mass Formula:

\[ \text{Exact Mass} = \sum (\text{Number of Atoms}_i \times \text{Exact Mass of Isotope}_i) \]

Exact Mass:

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1. What is Exact Mass?

Exact mass is the calculated mass of an ion or molecule determined using the mass of the most abundant isotope of each element. It differs from molecular weight, which uses average atomic masses.

2. How Does the Calculator Work?

The calculator uses the exact mass formula:

\[ \text{Exact Mass} = \sum (\text{Number of Atoms}_i \times \text{Exact Mass of Isotope}_i) \]

Where:

Number of Atoms — Count of each element in the molecule
Exact Mass of Isotope — Mass of the most abundant isotope for each element

Explanation: The calculator parses the molecular formula and sums the product of atom counts and their respective isotopic masses.

3. Importance of Exact Mass Calculation

Details: Exact mass calculation is crucial in mass spectrometry for compound identification, distinguishing between molecules with similar nominal masses but different elemental compositions.

4. Using the Calculator

Tips: Enter the molecular formula using standard notation (e.g., H2O, C6H12O6). Element symbols are case-sensitive (first letter uppercase, subsequent letters lowercase).

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between exact mass and molecular weight?
A: Exact mass uses the mass of the most abundant isotope of each element, while molecular weight uses the average atomic mass weighted by natural abundance.

Q2: Which elements are supported by this calculator?
A: The calculator supports common elements including H, C, N, O, F, P, S, Cl, Br, and I. Additional elements can be added to the isotope database.

Q3: How accurate is this exact mass calculator?
A: The accuracy depends on the precision of the isotopic masses used in the calculation. This calculator uses standard values with 6 decimal places.

Q4: Can this calculator handle complex formulas?
A: Yes, the calculator can parse most standard molecular formula notations, including those with multiple elements and subscripts.

Q5: Why is exact mass important in mass spectrometry?
A: High-resolution mass spectrometers can distinguish between compounds with very similar masses, making exact mass calculations essential for accurate compound identification.