All right, in this podcast we're going to cover the topic of mole fraction. Mole fraction is basically a part over whole situation. So it's the number of moles of whatever part you're trying to look at, whatever component of the system you're trying to look at, over the total number of moles. So if we're talking about like the mole fraction of a solution, it's the moles of whatever component you're talking about, so the solute over the total moles of the entire solution. So that would be considered a mole fraction. You can also do mole fractions for like pressures and other things. So it's not exclusive to solutions, even though in this example we are going to do a solution. So this question says what is the mole fraction of methanol in a solution that contains 1.25 moles of methanol and 2.22 moles of water. So we want the mole fraction of methanol, so we want methanol is our part, so 1.25 moles of methanol over our total moles. So to get our total moles we need to add these two things together. So to add those two things together, so when you add these together you get a total of 3.47 moles, pardon my handwriting. So that is our hole down here. So we have 1.25 over 3.47 and we get 0.36. That is our mole fraction. Mole fraction is this little crazy looking x, also known as chi. So it's very similar to a percentage except you do not multiply by 100, so it's part, over hole, and that's it. That's all you have to do.