formula.expert

Constants library

7 values, each with its units, its uncertainty, and where it came from.

Electromagnetic 1

Faraday constant exact

F=96485.33212331001 C/molF = 96485.33212331001\ \text{C/mol}

C/molThe charge carried by one mole of electrons, N_A×e ≈ 96485 coulombs — the bridge between the coulombs you meter and the moles you plate.

Chemistry 6

Standard Hydrogen Electrode Potential exact

E∘(H+/H2)=0 VE^{\circ}(\mathrm{H^+}/\mathrm{H_2}) = 0\ \text{V}

VThe standard potential of the hydrogen electrode, defined as exactly 0 V at 25 °C — the zero point of the entire electrochemical series.

Standard Potential of the Zinc Half-Cell measured

E∘(Zn2+/Zn)=−0.7618 VE^{\circ}(\mathrm{Zn^{2+}}/\mathrm{Zn}) = -0.7618\ \text{V}

VThe standard reduction potential of Zn²⁺ + 2e⁻ → Zn at 25 °C, −0.7618 V — the anode of the Daniell cell and of every sacrificial anode.

Standard Potential of the Copper Half-Cell measured

E∘(Cu2+/Cu)=0.3419 VE^{\circ}(\mathrm{Cu^{2+}}/\mathrm{Cu}) = 0.3419\ \text{V}

VThe standard reduction potential of Cu²⁺ + 2e⁻ → Cu at 25 °C, +0.3419 V — the cathode half of the Daniell cell and of copper electroplating.

Standard Potential of the Ferric–Ferrous Couple measured

E∘(Fe3+/Fe2+)=0.771 VE^{\circ}(\mathrm{Fe^{3+}}/\mathrm{Fe^{2+}}) = 0.771\ \text{V}

VThe standard reduction potential of Fe³⁺ + e⁻ → Fe²⁺ at 25 °C, +0.771 V — the redox couple that sets the character of natural water.

Standard Potential of the Silver Half-Cell measured

E∘(Ag+/Ag)=0.7996 VE^{\circ}(\mathrm{Ag^+}/\mathrm{Ag}) = 0.7996\ \text{V}

VThe standard reduction potential of Ag⁺ + e⁻ → Ag at 25 °C, +0.7996 V — the basis of the silver-silver chloride reference electrode.

Standard Potential of the Oxygen–Water Couple measured

E∘(O2/H2O)=1.229 VE^{\circ}(\mathrm{O_2}/\mathrm{H_2O}) = 1.229\ \text{V}

VThe standard reduction potential of O₂ + 4H⁺ + 4e⁻ → 2H₂O at 25 °C, +1.229 V — the couple that drives corrosion and limits water electrolysis.