## Applying La Chateliers

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

JustinHorriat_4f
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Joined: Wed Sep 18, 2019 12:19 am

### Applying La Chateliers

In the lecture, Professor Lavelle talked about how You can apply LA chateliers principle to E cell. I didn’t understand it. What happens when you increase one of the reactants? What happens to
The E of cell?

405318478
Posts: 90
Joined: Sat Jul 20, 2019 12:16 am

### Re: Applying La Chateliers

changing the concentration of the reactants changes E cell. Increasing the concentration of the products shifts the equilibrium to favor the products, thus E cell increases.

Long Luong 2H
Posts: 51
Joined: Thu Sep 19, 2019 12:16 am

### Re: Applying La Chateliers

Yes, Ecell is the voltage created by the difference in cell potentials. For instance, in a concentration cell, the higher the difference in concentrations between the cathode and anode, the more work can be done by the voltage that is created across the electrodes.

Jessica Chen 2C
Posts: 103
Joined: Thu Jul 11, 2019 12:17 am

### Re: Applying La Chateliers

In redox reactions (ie. Zn + 2H+ → Zn2+ + H2), the ion from the oxidation half-reaction (the anode) is a product (Zn2+), and the ion from the reduction half-reaction (the cathode) is a reactant (H+). In Le Chateliers principle, when you increase the concentration of reactants or decrease the concentration of products, the forward reaction is favored to balance out the change. So when you lower the amount of ion in the anode (lower the amount of product) and you increase the amount of ion in the cathode (increase the amount of reactant), the forward reaction is favored, and Ecell becomes more positive since the forward reaction is more likely to happen.

Charlene Datu 2E
Posts: 62
Joined: Wed Sep 11, 2019 12:16 am

### Re: Applying La Chateliers

You can also see this mathematically with the Nernst equation. Q is the ratio of products to reactants in a concentration cell. When you increase the concentration of the products, lnQ consequently decreases and Ecell becomes a more positive value. When you increase the concentration of the reactants, lnQ increases and Ecell becomes a more negative value. A higher Ecell results in a more favorable reaction, while a lower Ecell results in a less favorable reaction. This inversely applies when you lower the concentration as well.

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

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