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 (amu) 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 formula or SMILES notation to determine molecular weight:

Where:

• \( MW \) — Molecular weight in g/mol
• Each atomic mass is taken from the periodic table
• The sum includes all atoms in the molecule

Explanation: The calculator parses the input structure and sums the atomic weights of all constituent atoms.

3. Importance of Molecular Weight

Details: Molecular weight is essential for preparing solutions, calculating molarity, determining reaction yields, and in drug design where molecular properties affect bioavailability.

4. Using the Calculator

Tips: Enter the chemical structure in SMILES notation (e.g., "CCO" for ethanol, "CC(=O)O" for acetic acid). The calculator will parse the structure and calculate the molecular weight.

5. Frequently Asked Questions (FAQ)

Q1: What is SMILES notation?
A: SMILES (Simplified Molecular Input Line Entry System) is a chemical notation system that uses ASCII strings to represent molecular structures.

Q2: How accurate is this calculator?
A: Accuracy depends on the atomic mass data used. For precise work, use isotopic masses rather than average atomic weights.

Q3: Can it handle complex molecules?
A: A complete implementation would handle any valid SMILES string, including complex organic molecules and inorganic compounds.

Q4: What about hydrates or salts?
A: These should be entered with their full structural formula including water molecules or counterions.

Q5: Are there limitations?
A: Very large molecules (e.g., proteins) may be better handled by specialized software that accounts for post-translational modifications.