7. Gases
The Ideal Gas Law
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As we said, the ideal gas law uses r, which is our gas constant, but realize that the gas constant r can have 2 different values depending on the situation. Now the 2 terms you'll tend to see when it comes to the r constant is the first one we talked about earlier, r being equal to 0.08206. We utilize this value when dealing with the ideal gas law, but r can also equal 8.31 4. This happens when we're dealing with speed, velocity, or energy. So if a question is dealing with the speed of an object, or a subatomic particle, or dealing with the energy of a reaction or solution, the r converts to 8.314. Now the conversion factor between the r groups is that 1 liter times atmospheres equals 101.325 joules. So we have our point 08206 here. We use the conversion factor. So remember, we wanna get rid of liters times atmospheres, so we put them on the bottom. So 1 liters times atmosphere here on the bottom is 101.325 joules here on top. Liters times atmospheres cancel out and that's how we end up with joules at the end. When you plug this in, you get a long string of numbers as 8.314 7295 joules over moles times k. But we just focus on the 8.314 portion. I know there's a 7 there when you work it out completely, but to keep it simple, books will just list it as 8.314. So just keep in mind the gas constant can be 2 different numbers. And remember with the ideal gas law, we use this value, and when dealing with speed, velocity or energy, we use this value of 8.314.
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