The volume of a mole of gas can be found using a very specific formula. Find the volume of a mole of gas with help from a research scientist and one of the world's leading experts on star formation in this free video clip.

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The volume of a mole of gas can be found using a very specific formula. Find the volume of a mole of gas with help from a research scientist and one of the world's leading experts on star formation in this free video clip.

Part of the Video Series: Physics & Science Lessons

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Hello, my name is Harold Yorke, I'm a research scientist in Pasadena, California. And I want to explain, how do you determine the volume of a mole of gas? So, this number of atoms or molecules, that's equal to one mole. Now, a gas, as know, can expand or if you put it under pressure, can contract. And actually can fit into any volume you want it to fit into. If you compress it enough or if you let it expand enough. The formula to measure volume, pressure, temperature and with a certain, with one mole, is P times V equals N, that's the number of moles, times a constant called R, times T. If you want to know the volume, and you have on mole, N equals one. So, now, the volume is equal to this number R, multiplied by T and dividing that by pressure. Now, there's something called the standard pressure and temperature. And that is, if we had a pressure of one atmosphere. And we had a temperature equal to 32 Fahrenheit, that's zero Celsius. The Kelvin scale is two hundred and seventy three point one five Kelvin. That's your standard pressure and temperature. In that case, if I have that temperature and that pressure, the volume of one mole is twenty-two point four liters. So, let me remind you, twenty-two point four liters is the volume of one mole of gas at Standard Temperature and Pressure, STP is what this is called. If now, I want to know it at a different temperature and a different pressure, I'm going to use the ideal Gas Law. So, remember that the volume is equal to this constant R times T, divided by the pressure. And this is twenty-two point four liters times the temperature, divided by two hundred and seventy three point one five Kelvin. And I have to out the temperature in Kelvin. And I divide this by the pressure. So, that's one atmosphere divided by the pressure, again, given in atmospheres. So, that's how to calculate the volume of one mole of gas.