Equilibrium Constant K (Q) Units

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

KDang_1D
Posts: 127
Joined: Fri Aug 30, 2019 12:15 am
Been upvoted: 1 time

Equilibrium Constant K (Q) Units

Why can you use partial pressure and concentration together when calculating K or Q in the Nernst equation. Also, why can you use different units. 6N.3 combines atm and [ ], and 6N.5 combines bars and [ ]

Caroline Beecher 2H
Posts: 51
Joined: Wed Nov 14, 2018 12:21 am

Re: Equilibrium Constant K (Q) Units

Since K is unitless, I think that is part of why using both partial pressures and concentrations is okay in the Nernst Equation. The redox equations in these cases have both gases with partial pressures and solutions with different concentrations, so we want to use all components of the reaction when relating it to the Nernst Equation.

JohannaPerezH2F
Posts: 94
Joined: Wed Sep 18, 2019 12:18 am

Re: Equilibrium Constant K (Q) Units

you can combine them because K is unit less

Connor Chappell 2B
Posts: 59
Joined: Wed Feb 20, 2019 12:16 am

Re: Equilibrium Constant K (Q) Units

You can combine different values (i.e. pressure and concentration) because K is a unitless value. Therefore, if you're given concentration of some solution and pressure of a gas, you can use both to calculate Q, if they are involved in the equation for such calculation.

Return to “Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)”

Who is online

Users browsing this forum: No registered users and 3 guests