Solve Galvanic Cell Homework with Redox Table

[lha08]

Homework Statement

In a galvanic cell, how do we know which substance is the anode and which is the cathode by using the standard reduction potential chart (redox table)? Ex) Between Cu and Zn, which will donate electrons best...Ex) Pb+2 and Zn+2 which will accept electrons best...I'm really confused...

Homework Equations

The Attempt at a Solution

I looked at the values and apparently the higher the E, the more likely reduction will occur but when i compare Cu and Zn don't i have to flip the equation?

 

[nate808]

it is important to understand how to determine the anode and cathode in a galvanic cell using the standard reduction potential chart (redox table). The standard reduction potential (E°) is a measure of how easily a species is reduced, or gains electrons, in a redox reaction. The higher the E° value, the more likely the species is to be reduced.

To determine which substance is the anode and which is the cathode, you must first identify the half-reactions for each substance. In a galvanic cell, the anode is where oxidation occurs and the cathode is where reduction occurs.

To find the anode, look for the substance with the lower E° value. This substance is more likely to be oxidized, meaning it will lose electrons and become more positive. In the example given, Zn has a lower E° value than Cu, so Zn will be the anode.

To find the cathode, look for the substance with the higher E° value. This substance is more likely to be reduced, meaning it will gain electrons and become more negative. In the example given, Cu has a higher E° value than Zn, so Cu will be the cathode.

It is important to note that the equations given in the redox table are already balanced and do not need to be flipped. In the example given, the equation for Zn is Zn → Zn+2 + 2e- and the equation for Cu is Cu+2 + 2e- → Cu. These equations are already balanced and do not need to be flipped.

In the case of Pb+2 and Zn+2, you would need to compare their E° values to determine which one is more likely to be reduced and which one is more likely to be oxidized.

I hope this explanation helps clarify any confusion. If you need further assistance, please don't hesitate to reach out. it is important to understand and apply these concepts accurately. Keep up the great work!

 

[Blueshift5]

I understand your confusion with determining the anode and cathode in a galvanic cell using the standard reduction potential chart. The key to understanding this is to remember that the anode is where oxidation occurs and the cathode is where reduction occurs. In terms of the redox table, the substance with the higher standard reduction potential (E°) will be the cathode and the substance with the lower E° will be the anode. This is because the substance with the higher E° is more likely to accept electrons (reduction) while the substance with the lower E° is more likely to donate electrons (oxidation).

In the first example you provided, between Cu and Zn, Cu has a higher E° value of +0.34V compared to Zn's E° of -0.76V. This means that Cu is more likely to accept electrons (reduction) and therefore will be the cathode, while Zn will be the anode.

In the second example, between Pb+2 and Zn+2, Pb+2 has an E° of -0.13V while Zn+2 has an E° of -0.76V. Again, Pb+2 has a higher E° and is more likely to accept electrons (reduction), making it the cathode while Zn+2 will be the anode.

When comparing two substances with positive E° values, the substance with the higher E° will still be the cathode and the one with the lower E° will be the anode. This is because in a galvanic cell, the reaction will proceed in the direction of the more positive E° value.

I hope this explanation helps clarify how to determine the anode and cathode using the standard reduction potential chart. Remember to always consider which substance is more likely to accept or donate electrons and use the E° values as a guide.