Calculating K

$E_{cell} = E_{cell}^{\circ}-\frac{RT}{nF}\ln Q$

Felicia Fong 2G
Posts: 31
Joined: Sat Jul 22, 2017 3:00 am

Calculating K

The practice midterm test questions involve calculating K. However, a variety of formulas were used in the solutions. ∆G° = - RT ln K ,
Ecell=(RT/nF) ln K and E=Ecell-.05916V/n * logQ. Does it matter which formula we use?

rkusampudi
Posts: 58
Joined: Fri Sep 29, 2017 7:04 am

Re: Calculating K

Of the equations you listed, only the first two equations allow for you to calculate K, the last equation is Q which is the reaction quotient not the equilibrium constant.

Lauren Seidl 1D
Posts: 51
Joined: Fri Sep 29, 2017 7:06 am

Re: Calculating K

You can use either of the first two equations, depending on what values are given. If given deltaG directly, then the first equation is easier to use. If only given standard cell potential, then the second equation is easier to use. The third can be used when the reaction is not in equilibrium.

William Xu Dis 1D
Posts: 31
Joined: Fri Sep 29, 2017 7:05 am

Re: Calculating K

Either of the first two equations can be used. Just be sure to choose the one that is simplest used based off of the variables provided. For galvanic cells, the equation involving cell potential will likely be the best equation to use.

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