ΔE pilha (E°cat−E°ano)
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
About this calculator
The ΔE cell calculator (E°cat−E°an) determines the electromotive force (EMF) of an electrochemical cell. It computes the difference between the cathode's standard reduction potential (E°cat) and the anode's (E°an) using ΔE = E°cat − E°an. A positive result means the reaction is spontaneous; a negative result means it is not.
This tool is vital for studying redox processes in batteries or electroplating. Input cathode and anode values from standard potential tables. Note: confusing cathode and anode reverses the sign. Always cross-check with experimental conditions.
Example: If E°cat = +0.80 V (Ag⁺/Ag) and E°an = −0.76 V (Zn²⁺/Zn), ΔE will be +1.56 V, showing a Zn-Ag cell generates energy spontaneously. Inverted values would require an external power source.
Though simple, the calculator predicts electrochemical viability. It applies to galvanic (spontaneous) and electrolytic (non-spontaneous) cells but ignores factors like temperature or concentration, which affect real-world ΔE in labs.
Frequently asked questions
Why subtract anode potential from cathode potential?
Because the cathode undergoes reduction (gains electrons) while the anode undergoes oxidation (loses electrons). ΔE = E°cat − E°an reflects the reaction's natural tendency.
Where do standard E° values come from?
Use standard reduction potential tables from IUPAC or chemistry textbooks. Example: E°(Ag⁺/Ag) = +0.80 V; E°(Zn²⁺/Zn) = −0.76 V.
What if the result is negative?
A negative ΔE means the reaction is non-spontaneous and requires external energy, like in electrolysis.
Does this calculator account for non-standard conditions?
No. It uses standard conditions (25°C, 1 atm, 1 M concentrations). For other scenarios, apply the Nernst equation.