Nernst equation at 25 o c. Nernst equation last updated. T temperature kelvin which is generally 25 c.
nernst equation for cell potential
The nernst equation relates the effective concentrations activities of the components of a cell reaction to the standard cell potential.
Nernst equation for cell potential. Consider a metal in contact with its own salt. E e 0 00592n log 10 q. The nernst equation enables the determination of cell potential under non standard conditions. Standard cell potentials are calculated in standard conditionsthe temperature and pressure are at standard temperature and pressure and the concentrations are all 1 m aqueous solutionsin non standard conditions the nernst equation is used to calculate cell potentials.
When the cell potential equals zero the reaction is at equilibrium. Lets find the cell potential again for our zinc copper cell but this time the concentration of zinc two plus ions is 10 molar and we keep the concentration of copper two plus ions the same one molar. The nernst equation should give us that the cell potential is equal to the standard cell potential. Nernst equation can be used to find the cell potential at any moment in during a reaction or at conditions other than standard state.
Therefore as per the nernst equation the overall potential of an electrochemical cell is dependent on the reaction quotient. Save as pdf page id 273. In electrochemistry the nernst equation is an equation that relates the reduction potential of an electrochemical reaction half cell or full cell reaction to the standard electrode potential temperature and activities often approximated by concentrations of the chemical species undergoing reduction and oxidationit was named after walther nernst a german physical chemist who formulated. E cell potential v under specific conditions e cell potential at standard state conditions r ideal gas constant 8314 jmol k.
Derivation of nernst equation. It relates the measured cell potential to the reaction quotient and allows the accurate determination of equilibrium constants including solubility constants. For measurements carried out 298k the nernst equation can be expressed as follows. For a simple reduction of the form m n ne m it tells us that a half cell potential will change by 59 n mv per 10 fold change in the activity of the ion.
