Calculate The Formula Weight for Each of The Following Compounds

The formula weight (also known as molecular weight) of a chemical compound is the sum of the atomic weights of all the atoms in its molecular formula. This calculation is essential for stoichiometry, solution preparation, and chemical analysis. Our calculator provides accurate formula weights for any compound you input.

How to Calculate Formula Weight

To calculate the formula weight of a compound:

Identify the molecular formula of the compound.
Break down the formula into its constituent elements and their respective counts.
Multiply each element's atomic weight by its count in the formula.
Sum all these values to get the total formula weight.

Formula Weight Calculation

Formula Weight = Σ (Atomic Weight × Count of Each Element)

For example, the formula weight of water (H₂O) is calculated as:

2 × Atomic Weight of Hydrogen + 1 × Atomic Weight of Oxygen

2 × 1.008 + 1 × 16.00 = 18.016 g/mol

Formula Examples

Here are some examples of formula weight calculations:

Compound	Formula	Formula Weight (g/mol)
Water	H₂O	18.016
Sodium Chloride	NaCl	58.44
Glucose	C₆H₁₂O₆	180.16
Ethanol	C₂H₅OH	46.07

Common Chemical Compounds

Here are some common chemical compounds and their formula weights:

Carbon Dioxide (CO₂): 44.01 g/mol
Ammonia (NH₃): 17.03 g/mol
Methane (CH₄): 16.04 g/mol
Sulfuric Acid (H₂SO₄): 98.08 g/mol
Calcium Carbonate (CaCO₃): 100.09 g/mol

FAQ

What is the difference between formula weight and molar mass?

Formula weight and molar mass are essentially the same term. They refer to the sum of the atomic weights of all atoms in a molecule.

How accurate are the formula weights calculated by this tool?

Our calculator uses the most recent atomic weight values from the IUPAC (International Union of Pure and Applied Chemistry) to ensure accuracy.

Can I calculate the formula weight for any compound?

Yes, you can input any valid chemical formula, and our calculator will compute the formula weight for you.