What is Faraday's constant?

Faraday's constant (F) is 96,485 coulombs per mole of electrons. It represents the charge carried by one mole of electrons and is the fundamental link between electrical charge and chemical change.

What does ion charge (n) mean?

The ion charge (n) is the number of electrons transferred per ion during the electrode reaction. For Cu²⁺ it is 2, for Ag⁺ it is 1, for Al³⁺ it is 3. Using the wrong n gives the wrong mass.

How is gas volume calculated?

Moles of gas = moles of substance deposited. At STP (0 °C, 1 atm), 1 mol of any ideal gas occupies 22.4 L. At SATP (25 °C, 100 kPa), it occupies 24.8 L. The tool shows both.

What is the difference between Faraday's first and second law?

First law: mass deposited is proportional to charge passed (m ∝ Q). Second law: for the same charge, masses deposited of different substances are proportional to their equivalent weights (M/n). The formula m = QM/(nF) combines both.

Why does efficiency matter?

Real cells have side reactions and resistive losses, so the actual mass deposited is less than the theoretical value. Enter a current efficiency (%) to scale the result to realistic conditions.

Can I calculate time instead of mass?

Yes. Switch to "Find charge / time" mode, enter the target mass, and the tool returns the required charge in coulombs and the time at the entered current.

Faraday's Electrolysis Calculator

Name: Faraday's Electrolysis Calculator
Availability: InStock
Author: Nham Vu

Enter current, time, and select an element preset to instantly calculate the mass deposited or volume of gas evolved using Faraday's first and second laws.

Electrolysis Parameters

Element / Gas preset

Molar mass M (g/mol)

Ion charge n (e⁻/ion)

Current I (A)

Time

Current efficiency (%)

Select a preset and enter current + time, then click Calculate.

Common element presets

Species	M (g/mol)	n
Cu²⁺	63.55	2
Ag⁺	107.87	1
Zn²⁺	65.38	2
Fe²⁺	55.85	2
Al³⁺	26.98	3
Ni²⁺	58.69	2
Pb²⁺	207.2	2
Au³⁺	196.97	3
H₂↑	2.016	2
O₂↑	32.00	4
Cl₂↑	70.90	2

Summary