The electrodes in a silver oxide battery are silver oxide 1Ag2O2 and zinc (b) Which battery do you think has an energy density most similar to the silver oxide battery: a Li-ion battery, a nickel– cadmium battery, or a lead–acid battery? [Section 20.7]

Video transcript

Welcome back everyone in this example, we need to determine which statement is correct regarding a zinc carbon battery with zinc and manganese oxide electrodes. So we're going to begin by recalling what specific energy density of a battery is. So specific energy density we should recognize it's going to be the amount of energy a battery has in proportion to a tweet and it's recorded in what what hours per kilogram as its units. So we can understand that specific energy density is going to be related to the molar mass of the electrode materials and the voltage per cell of the battery. Which is why we see that on our image here, we have on our Y axis volumetric energy density recorded and then on the X axis specific energy density of our different battery types being recorded here. Now, going back to the prompt, it mentions that we have a zinc and manganese oxide type of battery, or rather a zinc carbon battery with the manganese oxide electrodes. And when we look up in our text books, the standard cell potential For a zinc carbon battery, we would see that we have a cell potential that is equal to a value of 1.5V. So this is from our textbook. So, recall that standard cell potential is represented by the Not so next based on our batteries. In our diagram, we see that our lithium ion battery which corresponds to the highest specific energy density since it's further to the right on our graph and has a high amount of volumetric energy. We would next want to look up what the lithium ion battery. Standard cell potential would be in our textbooks. And we would see that it corresponds to a value of 3.7V. Recall that the lithium ion is a plus one ion because it's located in group one a of our periodic table. Next in our graph, we have our nickel metal hydride battery here, which is our second highest as far as the specific energy density and volumetric energy density. We also want to recognize that our volumetric energy density tells us the size of our batteries here. So we would say that the further high value we have as far as the volumetric energy density that will correspond to a smaller size of our battery. And when we have a higher specific energy density, this will correspond to a lighter weight of our battery, so a lighter mass. And so with regard to our nickel metal hydride battery. When we look up in our text books, the standard cell potential for this type of battery, we would see that this corresponds to 1.2V. Next up, according to our chart, we have a nickel cadmium battery. And when we look up the standard cell potential for this type of battery in our textbooks, we see that it corresponds also to a value of 1.2V. So last we have our lead acid with the lowest specific energy density and lowest volumetric energy density. So it's the smallest battery with the heaviest weight. And we would see that our lead acid battery. And um in our textbooks has a standard cell potential corresponding to 2.0V. And so going back to our prompt, we need to consider the statements below to determine the battery that has the most similar Energy density to a zinc carbon battery. And looking at our options, since we know our zinc carbon battery has a cell potential or energy density of 1.5V. Or sorry, just a cell potential of 1.5 volts. We would see that according to our calculations from our textbook, the nickel cadmium battery has a cell potential of 1.2 volts as well as our nickel metal hydride battery which also had a cell potential of 1.2 volts. And since these two batteries have a cell potential, that is close to about 1.5 volts for ourself potential of our zinc carbon battery, we would confirm that the correct choice is going to be choice a It has an energy density most similar to a nickel metal hydride battery. Since the cell potentials were so close, we're going to assume that the energy densities of these batteries are also going to be related and close in value. So, a is going to be our final answer to complete this example. I hope everything I reviewed was clear. If you have any questions, please leave them down below. And I will see everyone in the next practice video.