Equivalent Weight Calculator Formula
Understand the math behind the equivalent weight calculator. Each variable explained with a worked example.
Formulas Used
Equivalent Weight
equiv_weight = molar_mass / n_factorVariables
| Variable | Description | Default |
|---|---|---|
molar_mass | Molar Mass(g/mol) | 98.08 |
n_factor | n-Factor | 2 |
How It Works
How to Calculate Equivalent Weight
Formula
Equivalent weight = Molar mass / n-factor
The n-factor depends on the reaction type (acid-base, redox, etc.).
Worked Example
H2SO4 (98.08 g/mol) as a diprotic acid (n=2).
molar_mass = 98.08n_factor = 2
- 01Eq. weight = 98.08 / 2
- 02Eq. weight = 49.04 g/equiv
Frequently Asked Questions
What is equivalent weight?
The mass of a substance that reacts with or supplies one mole of reactive species (H+, OH-, or electrons).
How do I find the n-factor?
For acids: number of H+ donated. For bases: number of OH-. For salts in precipitation: total charge. For redox: electrons transferred.
Is equivalent weight still used?
Less so in modern chemistry, but it remains useful in titration calculations and water chemistry.
Ready to run the numbers?
Open Equivalent Weight Calculator