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 molecular weight formula:

Where:

• \( atomic\_weights \) — Standard atomic weights of elements (g/mol)
• \( counts \) — Number of atoms of each element in the molecule

Explanation: The calculator sums the products of each element's atomic weight multiplied by its count in the molecule.

3. Importance of Molecular Weight

Details: Molecular weight is essential for preparing solutions, determining stoichiometry in reactions, calculating molarity, and in various analytical techniques like mass spectrometry.

4. Using the Calculator

Tips: Enter element symbols (e.g., C, H, O) separated by commas, followed by their counts in the same order. Example: "C, H, O" with counts "6, 12, 6" for glucose.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between molecular weight and molar mass?
A: They are numerically identical but molar mass is expressed in grams per mole (g/mol) while molecular weight is dimensionless.

Q2: How accurate are these calculations?
A: The calculator uses standard atomic weights. For precise work, use isotopic distributions or exact masses.

Q3: What if my element isn't in the database?
A: The calculator includes common elements. For others, you'll need to manually add their atomic weights.

Q4: How do I calculate MW for ionic compounds?
A: The same way - just include all atoms in the formula unit with their appropriate counts.

Q5: Why do some elements have decimal atomic weights?
A: Atomic weights account for natural isotopic abundance, so they're averages of different isotopes.