The Nernst Equation, formulated by German chemist ** Walther Nernst**, is one of the most important equations in electrochemistry. Electrochemical reactions occur in

**: closed loops consisting of two metallic conductors (**

*electrochemical cells***) suspended in an aqueous solution called an**

*electrodes***. Electrons are exchanged between the electrodes and the electrolyte. The Nernst Equation allows us to calculate useful information about the electrodes, discussed further below. Expect to find the results very stimulating.**

*electrolyte**By analyzing questions, you can see patterns emerge, patterns that will help you answer questions. Qwiz5 is all about those patterns. In each installment of Qwiz5, we take an answer line and look at its five most common clues. Here we explore five clues that will help you answer a tossup on the **Nernst Equation. *

__REDUCTION POTENTIAL__

In simplest terms, the Nernst Equation relates the ** reduction potential **of an electrochemical cell to the system’s electrode potential, temperature, and concentration of chemical species. The reduction potential refers to

**.**

*the tendency of electrons to be exchanged between electrolytes and electrodes in the cell*__REACTION QUOTIENT__** **

The Reaction Quotient is the measurement of ** amounts of products relative to reactants **in an electrochemical reaction

**In deriving the Nernst Equation, the**

*.***is multiplied by**

*natural logarithm of the reaction quotient***(the Universal gas constant x temperature). However, in order to complete the derivation, RT must be divided by another product (discussed below) so that the resulting reduction potential is**

*RT***.**

*in volts*__FARADAY’S CONSTANT__** **

Faraday’s Constant is denoted as ** F **in the Nernst Equation. This constant is

**. The product of RT, mentioned above, must be divided by the product of Faraday’s Constant and**

*the magnitude of electrical charge per mole of electrons***, where n is**

*n***. With these elements in place the Nernst Equation, in toto, is reproduced below:**

*the number of electrons transferred in the cell reaction***E = Eo - (RT/nF)lnQ**

Where E is the reduction potential

**Eo**is the electrode potential.**RT**is the universal gas constant x temperature**nF**is Faraday’s Constant x the number of electrons**lnQ**is the natural logarithm of the reaction quotient.

__THE GOLDMAN EQUATION __

The Goldman Equation is a “Nernst-like” equation used in ** biochemistry**. The Goldman Equation is specifically used in studying

**This equation determines the**

*cell membranes.***across a cell’s membrane. Reverse potential is the difference in electron potential across a cell membrane at which**

*reverse potential*

*no cells cross the cell membrane.*__BUTLER-VOLMER EQUATION__

Closely related to the Nernst Equation, the Butler-Volmer Equation relates the ** electrode current density **to the voltage difference between the electrodes and the electrolyte. When a reaction is at equilibrium, its Butler-Volmer Equation is

**.**

*transformed into the Nernst Equation****

*Quizbowl is about learning, not rote memorization, so we encourage you to use this as a springboard for further reading rather than as an endpoint. Here are a few things to check out: *

Visit

__this site__for a concise explanation of the Nernst Equation and how it relates to the activities of a galvanic cell.Walther Nernst contributed

__more__than just his eponymous equation to the world of physical chemistry. Check out some of his other work!To learn more about cell potentials in neurons, read

__this brief__article.Watch this video for a quick review of some key terms in electrochemistry:

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