How this calculation works
Electric charge counts transferred electrons, while a balanced electrode reaction determines how many electrons correspond to one unit of desired product. Product yield therefore depends on electron stoichiometry as well as current and time. This page applies Faraday charge balance with an entered current efficiency. It reports desired product amount and mass, with an optional ideal dry-gas volume under explicitly entered temperature and absolute pressure.
n_product = I t efficiency/(z F); mass=n M; optional dry ideal gas volume L=nRT_K/P_kPaA worked example
Passing twice the Faraday constant in coulombs through a reaction requiring two electrons per product unit at full current efficiency gives one mole of desired product. With molar mass 63.546, the modeled mass is 63.546 grams. For a gas with the same one-mole amount at zero Celsius and 101.325 kilopascals, ideal volume is about 22.414 litres. Changing product molar mass changes mass, but not that mole-based ideal volume.
Good to know
Side reactions are represented only through the entered efficiency, not predicted. Reaction balancing, gas dissolution, collection loss and water-vapor corrections are excluded from the simple charge and dry-gas balances. The result does not provide an electrolysis procedure or assess equipment hazards. Actual product identity, reaction conditions and safe operating practices require appropriate chemical and equipment guidance.
Reference: OpenStax — electrolysis and charge stoichiometry (opens in a new tab) ↗
What this calculation answers
Electric charge counts transferred electrons, while a balanced electrode reaction determines how many electrons correspond to one unit of desired product. Product yield therefore depends on electron stoichiometry as well as current and time.
This page applies Faraday charge balance with an entered current efficiency. It reports desired product amount and mass, with an optional ideal dry-gas volume under explicitly entered temperature and absolute pressure.
The Molecular weight and molar mass calculator checks product molar mass. Charge-based yield also needs the electron stoichiometry of the intended electrode reaction and entered current efficiency.
Use the right input conventions
Current is amperes and duration seconds, so their product is coulombs. Electron count must come from the intended balanced electrode reaction; the calculator does not identify products from a material name.
Current efficiency is the percentage of total charge assigned to that desired product. It is distinct from energy efficiency and does not include a voltage input, overpotential or electrical cost calculation.
Interpret the result
Moles of product equal useful charge divided by electron number and the Faraday constant. Multiplying by entered molar mass gives grams. A zero current, duration or efficiency produces zero modeled yield.
Gas mode additionally requires Celsius temperature and absolute kilopascal pressure. It applies the ideal gas law to dry product only; gauge pressure and a wet collection volume need additional information.
Work through the example
Passing twice the Faraday constant in coulombs through a reaction requiring two electrons per product unit at full current efficiency gives one mole of desired product. With molar mass 63.546, the modeled mass is 63.546 grams.
For a gas with the same one-mole amount at zero Celsius and 101.325 kilopascals, ideal volume is about 22.414 litres. Changing product molar mass changes mass, but not that mole-based ideal volume.
Where the model stops
Side reactions are represented only through the entered efficiency, not predicted. Reaction balancing, gas dissolution, collection loss and water-vapor corrections are excluded from the simple charge and dry-gas balances.
The result does not provide an electrolysis procedure or assess equipment hazards. Actual product identity, reaction conditions and safe operating practices require appropriate chemical and equipment guidance.
A few questions, answered
Is current efficiency the same as energy efficiency?
No. It allocates charge to the desired product; energy efficiency would also require voltage and energy information.
What changes in the comparison?
Switch to dry gas reporting and inspect the additional temperature and absolute-pressure inputs without changing product moles.