Equivalent Weight Calculator

How to Use the Calculator

1. Enter the Molecular Weight of the substance in g/mol. This is the sum of the atomic weights of all atoms in a molecule.
2. Enter the Valency (or charge) of the substance. This is the number of electrons that an atom can lose, gain, or share when forming chemical bonds.
3. Click the Calculate button to compute the equivalent weight.
4. The result will be displayed in g/mol.

What is Equivalent Weight?

The equivalent weight of a substance is defined as the molecular weight divided by the valency. It is used in stoichiometry to express the reactive capacity of a substance in chemical reactions.

Formula

Equivalent Weight = Molecular Weight / Valency

Applications

• Acid-base reactions: The equivalent weight of an acid is used to determine the amount of base that will neutralize it completely.
• Redox reactions: The equivalent weight of a reducing or oxidizing agent helps determine the amount needed for complete reaction.
• Precipitation reactions: Equivalent weights are used to calculate the amount of precipitating agent needed.

Example

For sulfuric acid (H₂SO₄) with a molecular weight of 98 g/mol and a valency of 2 (as it can provide 2 H⁺ ions), the equivalent weight would be:

Equivalent Weight = 98 g/mol / 2 = 49 g/mol