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 formula:

Where:

• Atomic mass — Weight of a single atom of the element (from periodic table)
• Count — Number of atoms of that element in the molecule

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

3. Importance of Molecular Weight

Details: Molecular weight is essential for preparing solutions, determining reaction yields, calculating molarity, and understanding physical properties of substances.

4. Using the Calculator

Tips: Enter chemical formula using standard notation (e.g., C6H12O6 for glucose). Case matters - element symbols start with uppercase letter (Na for sodium, not NA).

5. Frequently Asked Questions (FAQ)

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

Q2: How are atomic masses determined?
A: Atomic masses are weighted averages of all naturally occurring isotopes of an element, based on their abundance.

Q3: What about hydrates or salts?
A: Include water molecules or counterions in the formula (e.g., CuSO4·5H2O for copper sulfate pentahydrate).

Q4: Why are some atomic masses not whole numbers?
A: Most elements have multiple isotopes with different masses, and the atomic mass reflects their natural abundance.

Q5: What if my formula contains parentheses?
A: This calculator handles simple formulas. For complex formulas with nested parentheses, use a more advanced calculator.