At 273 K and 1 atm pressure, 1 mol of an ideal gas occupies 22.4 L. (Section 10.4) (c) In which parts of the atmosphere would you expect gases to behave most ideally (ignoring any photochemical reactions)? [Section 18.1]

Video transcript

Hey everyone today we're being asked under which of the three following conditions would a gas behave most ideally. So, the three conditions are with high temperature and low pressure, low temperature and high pressure and finally, both average temperature and pressure before identifying which one would be best. However, the main thing to notice that in the questions asking which in which would a gas behave most ideally? And that key is the ideally that means you're dealing with the concept of an ideal gas and ideal gasses have a few postulates that go along with them. So let's take a look at those. So, for ideal gasses for an ideal guess, we assume that it has one random constant motion between all of its particles. Randomness random motion will say to the combined volume of the particles are negligible, volume negligible. Three. The particles exert no force on each other, no force for any collisions between the particles are completely elastic, elastic collisions, coalitions and finally that the average kinetic energy of the particles is proportional to its temperature in kelvin's. So the kinetic energy is proportional to temperature in kelvin. So with these five postulates, we can go ahead and take a look at our answer choices now from off the bat, we can actually rule out option choice C. And we'll work our way up. But this is because at average temperature and pressure, we would actually expect a pretty average performance of the gas, ideally, it wouldn't be the best. It wouldn't be absolutely ideal, but it wouldn't be too bad either. It would just be about normal in a low pressure or low temperature high pressure situation such as in question or answer choice B. We would run into some problems though. And let's draw this out. We have low temperature and high pressure. Let's say we have a box. So high pressure means that there is a large force that is being exerted upon the particles. Right? And let's say we have some gas particles in here. We have 12. Just some gas particles floating around in high pressure, which can also be achieved by a smaller volume and at a lower temperature some things happen here. So because of the high pressure, the volume of the gas molecules can no longer be considered negligible because there's less empty space. Let's write that out. There's less empty space between each of the gas molecules. Which means that since there's less space between them, we have to consider the fact that their volume does exist. Now. We don't have enough space to assume that the volume wouldn't have a really big effect on their behavior. Similarly at a low temperature, the kinetic energy of the gas decreases because remember as gas or as temperature decreases. Solo kinetic energy, they are directly proportional. So since this happens, the attractive forces between the molecules are more prominent, which means they will behave in a non ideal matter. They will be more attractive or repulsive to each other and that that force will be much more magnified than it would be at an ideal situation and in ideal conditions. So we can rule out be as an answer choice which leaves us with a which is indeed our correct answer because it's exactly the opposite of question. Be at a high temperature, we would have uh more kinetic energy, which means the attractive forces of the gas molecules are less prominent because they're zooming everywhere, they're bouncing off of each other. So their excitement overcomes the fact that there may be forces or attractive forces between the molecules. Similarly due to the low pressure, the pressure will be lower, which means there will be more empty space between the gas molecules and their volume can be considered negligible again. So the answer is a high temperature and low pressure conditions would allow gas to behave most ideally. I hope this helps. And I look forward to seeing y'all in the next one.