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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: Sophia7X on March 20, 2012, 03:22:36 PM

Title: Do you include gases in the reactant quotient if you have aqueous things?
Post by: Sophia7X on March 20, 2012, 03:22:36 PM

For example, if you were trying to calculate E cell, and the equation involved aqueous ions as well as gases, do you include the gas in Q? Or just the aqueous ions?
Thanks.

Title: Re: Do you include gases in the reactant quotient if you have aqueous things?
Post by: Borek on March 20, 2012, 04:11:40 PM

For a hydrogen electrode potential is

$$E = \frac {RT} {2F} \ln \frac {[H^+]^2} {p_{H_2}}$$

Note that "standard" electrode requires exactly 1 atm of hydrogen pressure.