Consider a twofold expansion of 1 mol of an ideal gas at 25 °C in the isolated system shown in Figure 18.1. (b) How does this process illustrate the second law of thermodynamics?

Video transcript

Hello everyone. So this video being told that we have one mole of this ideal gas experiences a three fold expansion in the isolated system depicted in this figure here, we want to explain how this process demonstrates the second law of thermodynamics. So what is the second law of thermodynamics? Let's go ahead and write this out. So just short enough just to be the second law. So what the state is that the entropy of an isolated system always increases and the system tens to move spontaneously towards a maximum state of disorder. So we want a high entropy basically. So shown in this figure here, the molecules of gas X and bulb one expand spontaneously. As said in this ford arrow here to our bulbs to and bulbs three when the stop cocks are open. So these are the stop cocks here. Therefore the entropy of the system continues to increase until it reaches its maximum states all this is filled. So the compression of the molecules of gas X. To build one does not occur spontaneously. And you can see from this backwards area here is non spontaneous and not occur on its own because it is non spontaneous. So what this means is that is the process occurs in an isolated system. We can go ahead and conclude bread and red that are dealt to us for our surroundings is equal to zero. So we can recall for a spontaneous process that the total delta S. Delta S. Sub total is going to have to be greater than zero. So basically a positive value. Let's go ahead. Also recall that DELTA S. Total. The equation for this is equal to delta us for our system plus the delta S. For our surroundings. So basically this is very established that our delta S of surroundings is equal to zero. We kind of just eliminate this from the problem. So then our equation would be delta S. Total is equal to adopt us of our system. This needs to be greater than zero, or rather a positive value. So for my answer for this, let's go ahead and write this below. Our answer is that the gas molecules of our deal gas X. Expanded spontaneously. And what this means that it increases the entropy. Go ahead, scroll down of the system until it reaches its maximum state. The maximum state just means the highest level of disorder. So this right here is going to be my final answer for this problem. Thank you all so much for watching.