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).

2. How to Calculate Molecular Weight

The molecular weight is calculated using the formula:

Steps:

1. Identify all elements in the molecule
2. Find each element's atomic mass from the periodic table
3. Count the number of atoms of each element
4. Multiply each element's atomic mass by its count
5. Sum all these values to get the molecular weight

3. Importance of Molecular Weight

Applications: Molecular weight is crucial for stoichiometric calculations, preparing solutions with specific molarity, determining molecular structure, and in polymer chemistry.

4. Using the Calculator

Instructions: Enter the chemical formula (e.g., H2O for water, C6H12O6 for glucose). The calculator will sum the atomic masses of all atoms in the formula.

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 do I calculate MW for ionic compounds?
A: The process is the same - sum the atomic masses of all atoms in the formula unit (e.g., NaCl = 22.99 + 35.45 = 58.44 g/mol).

Q3: What about hydrates?
A: Include water molecules in the calculation (e.g., CuSO4·5H2O includes 5 water molecules).

Q4: How accurate is this calculator?
A: Accuracy depends on the atomic mass values used. We use IUPAC recommended atomic weights.

Q5: Can this calculate formula weight?
A: Yes, formula weight (for ionic compounds) is calculated the same way as molecular weight.