1. What is Molecular Weight?

Molecular weight (MW) is the sum of the atomic weights of all atoms in a molecule. It's expressed in atomic mass units (u) or grams per mole (g/mol) and is crucial for stoichiometric calculations in chemistry.

2. How Does the Calculator Work?

The calculator uses the molecular weight formula:

Where:

• \( MW \) — Molecular weight (g/mol)
• \( \text{atomic\_masses} \) — Standard atomic weights of elements (g/mol)
• \( \text{counts} \) — Number of each atom in the molecule

Explanation: The calculator parses the chemical formula, looks up each element's atomic mass, multiplies by the atom count, and sums all values.

3. Importance of Molecular Weight

Details: Molecular weight is essential for preparing solutions, stoichiometric calculations, determining empirical formulas, and converting between mass and moles in chemical reactions.

4. Using the Calculator

Tips: Enter the chemical formula using standard notation (e.g., H2O, C6H12O6). Element symbols are case-sensitive (Na for sodium, not NA). Numbers after elements indicate atom counts (omit for 1).

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between molecular weight and molar mass?
A: They're numerically identical but molar mass is the mass of one mole of substance (g/mol), while molecular weight is dimensionless (though often reported in g/mol).

Q2: How accurate are these calculations?
A: Accuracy depends on the atomic weight data used. This calculator uses standard atomic weights from IUPAC.

Q3: Does this work for ionic compounds?
A: Yes, the calculation works the same way for ionic compounds (e.g., NaCl) and covalent molecules.

Q4: What about hydrates or other special formulas?
Q5: Why is my calculated MW different from literature values?
A: Some elements have isotopic variations. Literature values may use different atomic weight data or account for natural isotopic abundance.