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).

2. How Does the Calculator Work?

The calculator sums atomic weights of all atoms in the drawn structure:

Process:

1. User draws or inputs molecular structure
2. System identifies all atoms in the structure
3. Looks up atomic weights from periodic table
4. Sums weights of all atoms

3. Importance of Molecular Weight

Applications: Essential for stoichiometric calculations, preparing molar solutions, determining empirical formulas, and in mass spectrometry.

4. Using the Calculator

Instructions: Draw the molecular structure using the chemical drawing tool or input the structure in SMILES, InChI, or other chemical notation formats.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between molecular weight and molar mass?
A: They are numerically identical but molar mass has units of g/mol while molecular weight is dimensionless.

Q2: How accurate are these calculations?
A: Accuracy depends on the atomic weight data used. Most calculators use IUPAC standard atomic weights.

Q3: Does this account for isotopes?
A: Basic calculators use average atomic weights. For exact isotopic calculations, specialized tools are needed.

Q4: Can I calculate MW for polymers?
A: For polymers, you typically calculate the molecular weight of the repeating unit.

Q5: What about salts and hydrates?
A: Include all atoms in the formula unit, including water molecules in hydrates or counterions in salts.