1. What is Molecular Weight?

Molecular weight (MW) is the sum of the atomic weights of all atoms in a molecule's formula. It's expressed in atomic mass units (amu) or grams per mole (g/mol).

2. How Does the Calculator Work?

The calculator uses the molecular formula associated with the structure number to compute:

Where:

• Each element's atomic mass is summed according to its count in the formula
• Standard atomic weights are used from IUPAC tables
• Structure numbers are mapped to their corresponding molecular formulas

3. Importance of Molecular Weight

Details: Molecular weight is crucial for stoichiometric calculations, preparing molar solutions, determining reaction yields, and in drug dosage calculations.

4. Using the Calculator

Tips: Enter the structure number exactly as it appears in your database or chemical catalog. The system will retrieve the corresponding molecular formula and calculate the weight.

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: Calculations use standard atomic weights. For precise work, use isotopic masses and exact composition.

Q3: Can I calculate MW for mixtures?
A: This calculator is for pure compounds. For mixtures, you would need to calculate an average molecular weight.

Q4: What if my structure number isn't recognized?
A: Verify the number or consult your chemical database administrator. New compounds may need to be added.

Q5: How are hydrates handled?
A: Water molecules in hydrates are included in the MW calculation if specified in the structure's formula.