Show the approximate level of the movable piston in drawings (a), (b), and (c) after the indicated changes have been made to the gas.

Video transcript

Welcome back everyone. We need to determine which of the following images illustrates the gas sample. After the indicated changes are applied. So what we are given is an initial temperature of 200 kelvin and an initial pressure of 2000.8 E A t M's. Looking at diagram a. We have a final temperature of 2 50 kelvin. So it appears that the temperature increases where we have an initial pressure of 500.80 M. So it looks like pressure is consistent with regards to diagram A and what we want to think of is Charles law when pressure is constant. So we would recall that Charles law when pressure is constant, describes our initial volume divided by our initial temperature equal to the final volume divided by the final temperature where for diagram a isolating for the final volume. We want to see that the initial volume is going to be multiplied by the final volume and divided by our initial temperature. So, plugging in what we know from our Diagram, we have our initial volume which we don't know multiplied by the final temperature being 250 Kelvin for a Divided by our initial temperature from our prompt as 200 Kelvin And simplifying this, we would get that our final volume is equal to our initial volume times a factor of 1.25. And because this is greater in value will say that the volume will increase, sits this increasing by a factor greater than one. So moving on to part B, we should recognize that we go from an initial temperature to still a final temperature in diagram B of 200 kelvin. So here we have constant temperature where our initial pressure 2000.80 A T. M's increases in diagram B to a pressure of 1.20 A t M's. So for diagram B we're going to recall Boyle's law When temperature is constant, recall that when temperature is constant. Boyle's law says that our initial pressure times our initial volume is equal to the final pressure times the final volume. So isolating for the final volume. Sorry. So isolating for final volume, we would say that we have our initial pressure times the initial volume divided by our final pressure. So plugging in what we know from our diagram We have our initial pressure being 0.80 ATS, Multiplied by the initial volume, which we don't know divided by our final pressure for Diagram B, which was 1.20 ATMs. And what we're going to simplify too is that our final volume is equal to .67 times our initial volume. And so because this factor is less than one, we would say that therefore volume will decrease. So looking at our answer choices beginning with choice A. We see that we have our volume of our gas consistent and choices A and B. So let's rule that out because we know it should increase in choice A. And to decrease in choice B. Moving onto choice B. We show an increase in our volume of our gas here, so increase volume check mark here and then for diagram B. We have a decrease in our volume of our gas so we can check mark that off, meaning that choice B looks like a correct choice. But let's keep considering our options. So looking at choice C. We see that we have constant volume which we can already rule out choice C. Out because we know that in diagram a volume should increase. So moving on to choice D. We see that volume decreases and we know that in diagram A. It should increase. So will rule out choice D. Meaning that the only correct choice to complete this example is going to be Choice B. Which shows our diagrams for A. And B. Where in A. We have an increased volume and in diagram B we have a decreased volume. So B is going to be our final answer. To complete this example. I hope everything I explained was clear. If you have any questions, please leave them down below and I will see everyone in the next practice video.