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 various chemical calculations.

2. How Does the Calculator Work?

The calculator uses the molecular weight formula:

Where:

• \( MW \) — Molecular weight in g/mol
• \( \sum \) — Sum of all atomic masses
• Each atomic mass is multiplied by its count in the molecule

Example: For water (H₂O), MW = (2 × 1.008) + (1 × 15.999) = 18.015 g/mol

3. Importance of Molecular Weight

Details: Molecular weight is essential for stoichiometric calculations, preparing solutions, determining reaction yields, and in biochemical applications like protein analysis.

4. Using the Calculator

Tips:

• Enter element symbols (e.g., C,H,O,N)
• Enter corresponding counts (e.g., 6,12,6,1 for glucose)
• Use standard element symbols (case sensitive)
• For elements with two letters (like Na), don't use spaces

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between molecular weight and molar mass?
A: They're numerically identical but molecular weight refers to single molecules while molar mass refers to one mole of substance.

Q2: How accurate are these calculations?
A: They use average atomic weights. For precise work, use isotopic composition-specific weights.

Q3: Can I calculate MW for large biomolecules?
A: Yes, but for proteins consider using amino acid sequence calculators which account for water loss in peptide bonds.

Q4: Why are atomic weights not whole numbers?
A: Atomic weights account for natural isotopic abundance of each element.

Q5: How do I calculate MW for ionic compounds?
A: The same way - just include all atoms in the formula unit (e.g., NaCl = Na + Cl).