1. What is Molar Mass?

Molar mass is the mass of one mole of a substance, typically expressed in grams per mole (g/mol). It is calculated by summing the atomic weights of all atoms in a chemical formula.

2. How to Calculate Molar Mass

The molar mass is calculated using the formula:

Where:

• \( AW \) — Atomic weight of each element (g/mol)
• \( n \) — Number of atoms of each element in the compound
• \( \sum \) — Sum of all (AW × n) products

Example: For water (H₂O):

• Hydrogen: 2 atoms × 1.008 g/mol = 2.016 g/mol
• Oxygen: 1 atom × 15.999 g/mol = 15.999 g/mol
• Total molar mass = 2.016 + 15.999 = 18.015 g/mol

3. Importance of Molar Mass

Details: Molar mass is fundamental in stoichiometry for converting between mass and moles of a substance. It's essential for preparing solutions, calculating reaction yields, and determining empirical and molecular formulas.

4. Using the Calculator

Tips: Enter the chemical formula using standard notation (e.g., H2O, C6H12O6, NaCl). The calculator will parse the formula and sum the atomic weights of all atoms.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between molecular mass and molar mass?
A: Molecular mass is the mass of one molecule (in atomic mass units), while molar mass is the mass of one mole of molecules (in g/mol). Numerically they are equal but have different units.

Q2: How do I calculate molar mass for hydrated compounds?
A: Include the water molecules in the formula. For example, for CuSO₄·5H₂O, include all atoms: Cu, S, 4O, 10H, and 5O.

Q3: What if my compound contains parentheses?
A: This calculator handles simple formulas. For formulas with parentheses like Ca(OH)₂, enter as CaO2H2.

Q4: Why are atomic weights not whole numbers?
A: Atomic weights are weighted averages of naturally occurring isotopes, which is why they often have decimal values.

Q5: How accurate are the calculations?
A: The calculator uses standard atomic weights. For precise work, use the specific isotopic composition of your sample.