May 25, Lastly, this video may help introduce you to the ideal gas law. I hope this is helpful. Related questions How does Boyle's law relate to breathing? And what would happen to n How do you find the moles of a substance or the molecular formula with gas laws?
What is Avogadro's Law? The problems lie almost entirely in the units. I am assuming below that you are working in strict SI units as you will be if you are doing a UK-based exam, for example. Pressure is measured in pascals, Pa - sometimes expressed as newtons per square metre, N m These mean exactly the same thing.
Be careful if you are given pressures in kPa kilopascals. For example, kPa is Pa. You must make that conversion before you use the ideal gas equation. This is the most likely place for you to go wrong when you use this equation. That's because the SI unit of volume is the cubic metre, m 3 - not cm 3 or dm 3. So if you are inserting values of volume into the equation, you first have to convert them into cubic metres.
Similarly, if you are working out a volume using the equation, remember to covert the answer in cubic metres into dm 3 or cm 3 if you need to - this time by multiplying by a or a million. If you get this wrong, you are going to end up with a silly answer, out by a factor of a thousand or a million. So it is usually fairly obvious if you have done something wrong, and you can check back again. This is easy, of course - it is just a number. You already know that you work it out by dividing the mass in grams by the mass of one mole in grams.
I don't recommend that you remember the ideal gas equation in this form, but you must be confident that you can convert it into this form. A value for R will be given you if you need it, or you can look it up in a data source. The SI value for R is 8. Note: You may come across other values for this with different units. A commonly used one in the past was The units tell you that the volume would be in cubic centimetres and the pressure in atmospheres.
Unfortunately the units in the SI version aren't so obviously helpful. The temperature has to be in kelvin. Don't forget to add if you are given a temperature in degrees Celsius. Calculations using the ideal gas equation are included in my calculations book see the link at the very bottom of the page , and I can't repeat them here.
There are, however, a couple of calculations that I haven't done in the book which give a reasonable idea of how the ideal gas equation works. If you have done simple calculations from equations, you have probably used the molar volume of a gas. Google Classroom Facebook Twitter.
Video transcript - [Instructor] In this video we're gonna talk about ideal gasses and how we can describe what's going on with them. So the first question you might be wondering is, what is an ideal gas? And it really is a bit of a theoretical construct that helps us describe a lot of what's going on in the gas world, or at least close to what's going on in the gas world. So in an ideal gas, we imagined that the individual particles of the gas don't interact.
So particles, particles don't interact. And obviously we know that's not generally true. There's generally some light intermolecular forces as they get close to each other or as they pass by each other or if they collide into each other. But for the sake of what we're going to study in this video, we'll assume that they don't interact. And we'll also assume that the particles don't take up any volume. Don't take up volume. Now, we know that that isn't exactly true, that individual molecules of course do take up volume.
But this is a reasonable assumption, because generally speaking, it might be a very, very infinitesimally small fraction of the total volume of the space that they are bouncing around in. And so these are the two assumptions we make when we talk about ideal gasses. That's why we're using the word ideal. In future videos we'll talk about non-ideal behavior. But it allows us to make some simplifications that approximate a lot of the world.
So let's think about how we can describe ideal gasses. We can think about the volume of the container that they are in. We could imagine the pressure that they would exert on say the inside of the container. That's how I visualize it. Although, that pressure would be the same at any point inside of the container. We can think about the temperature. And we wanna do it in absolute scale, so we generally measure temperature in kelvin.
And then we could also think about just how much of that gas we have. And we can measure that in terms of number of moles.
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