A 1:1 mixture of helium (red) and argon (blue) at 300 K is portrayed below on the left. Draw the same mixture when the temperature is lowered to 150 K.

Video transcript

Welcome back everyone. We're told that the illustration below shows a 1 to 1 mixture of neon green and krypton in blue, at 400 kelvin. What will be the illustration if the temperature of the mixture is lower to 200 kelvin. So we have the four below options to consider from And we're going to first recognize that Neon and Krypton on our periodic table are found in group eight a. Which we want to recall is our noble gas group. And so what's depicted in our illustrations are our gaseous mon atomic molecules of krypton and neon. And we want to recall that gasses are constantly moving in random motion and this random motion is caused by the high amount of entropy which we want to recall is represented by the symbol. S So this high amount of entropy which we should recognize means disorder of our gas molecules causes this random motion of these gaseous molecules of krypton and neon. And so with this being recalled, we want to recognize that in general entropy is going to increase with increasing temperature. So from our prompt we see that the temperature lowers from 400 Kelvin to a final temperature, We would say TF equal to 200 Kelvin. So since temperature is lowered, we would say that temperatures lowered and so therefore entropy is most likely going to be lowered since temperature and entropy seem to be directly related. And so if we know that entropy means disorder of our gas molecules and temperatures lowered, lowering the disorder of our gas molecules. We want to pick an illustration where we have more order between our gas molecules and looking at our options, we can see that choice is A versus B. We would definitely find more of a random arrangement for choice B. So we're going to rule out choice B. We don't think it looks correct, but Choice A definitely looks a bit more neat. Where are blue molecules are more towards the left and our green molecules are grouped towards the right of the blue ones. So A looks like a good prospect for an answer choice. Now looking at choice, see we see that our gas molecules are still kind of mixed together and some of them even looked like they've reacted to form a compound here. So let's actually rule out choice C. Since we also don't want to agree with that image. And then we have choice D. Where we still have some of our green gaseous molecules mixed in with our blue gaseous molecules. So choice D. Is still a bit High in entropy. So we would rule it out, meaning that the only correct image for what our gas molecules will appear once the temperature is lowered to 200 Kelvin is going to be choice a where we have less, entropy. meaning we have more organization of our gas molecules since it's less disordered. So A would be our final answer to complete this example since our gas mixture is less random. If you have any questions, please leave them down below. and I'll see everyone in the next practice video.