1. What Is Molecular Weight?

Molecular weight (MW) is the sum of the atomic masses of all atoms in a molecule, expressed in grams per mole (g/mol). It's a fundamental property used in chemistry to relate mass to number of molecules.

2. How Does The Calculator Work?

The calculator uses the molecular weight formula:

Where:

• \( n_i \) — Number of atoms of element i
• \( atomic\_mass_i \) — Standard atomic mass of element i (g/mol)

Explanation: The calculator parses the chemical formula, identifies elements and their counts, then sums the product of each element's count and its atomic mass.

3. Importance Of Molecular Weight Calculation

Details: Molecular weight is essential for stoichiometric calculations, preparing solutions with specific concentrations, determining reaction yields, and in various analytical techniques like mass spectrometry.

4. Using The Calculator

Tips: Enter the chemical formula using standard notation (e.g., H2O, C6H12O6, NaCl). Use proper capitalization (e.g., Co for cobalt vs CO for carbon monoxide).

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between molecular weight and formula weight?
A: Molecular weight refers to molecules, while formula weight is used for ionic compounds. Both are calculated similarly as the sum of atomic masses.

Q2: How accurate are the atomic masses used?
A: This calculator uses standard atomic masses with 2-4 decimal places. For precise work, use IUPAC-recommended values with appropriate significant figures.

Q3: Can this calculator handle complex formulas?
A: This version handles basic formulas. For hydrates, coordination compounds, or complex ions, specialized calculators may be needed.

Q4: What about isotopic variations?
A: This calculator uses average atomic masses. For specific isotopes, use the exact mass of the isotope instead.

Q5: How is molecular weight used in solution preparation?
A: Molecular weight is used to calculate molarity (mol/L) when preparing solutions: mass (g) = molarity (M) × volume (L) × MW (g/mol).