1. What is Molecular Weight?

Molecular weight is the sum of the atomic masses of all atoms in a molecule. It is expressed in atomic mass units (u) and is crucial for identifying compounds in mass spectrometry.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( \text{Atomic Mass}_i \) — Atomic mass of element i (u)
• \( \text{Number}_i \) — Number of atoms of element i in the molecule

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

3. Importance in Mass Spectrometry

Details: Accurate molecular weight calculation is essential for interpreting mass spectra, identifying unknown compounds, and confirming molecular structures.

4. Using the Calculator

Tips: Enter elements and their counts in the format "Element:Count" separated by commas (e.g., "C:6,H:12,O:6"). Use standard element symbols.

5. Frequently Asked Questions (FAQ)

Q1: What atomic mass values are used?
A: The calculator uses standard atomic weights based on IUPAC recommendations.

Q2: How accurate is this calculation?
A: The calculation provides theoretical molecular weight. Actual measurements may vary slightly due to isotopic distributions.

Q3: Can I calculate molecular weight for ions?
A: For ions, adjust the calculation by adding/subtracting the mass of electrons gained/lost.

Q4: What about isotopic variants?
A: This calculator uses average atomic masses. For exact isotopic calculations, specialized software is needed.

Q5: How does this help in mass spec analysis?
A: Comparing calculated molecular weights with measured m/z values helps identify molecular ions and fragment ions.