A flask contains a mixture of neon (Ne), krypton (Kr), and radon (Rn) gases. Compare (b) the root-mean-square speeds. (Hint: Appendix D shows the molar mass (in g/mol) of each element under the chemical symbol for that element.)

Video transcript

Welcome back everybody. We are told that three different gasses, Helium Argon and xenon are all placed in the same tank and isolated from the atmosphere. And we are asked to compare the root mean square speeds of these three gasses. So we're going to have some sort of comparative signals or symbols here. So in order to compare the root mean squares, we need to kind of know the formula for it. Well, the formula for root mean squares, beads is going to be the square root of three times. Our ideal gas constant times are absolute temperature divided by our molar mass. Now, since it's placed in the same tank, the numerator here is going to be constant, meaning that the molar mass term of each of our gasses is going to be the determining factor in the root mean square speed for each of these gasses, A. K. A. The root mean square speed is inversely proportional to moller mass. Well, let's compare the molar masses of these three gasses. If you'll notice or if you look at a periodic table, you'll actually see that as we move to the right here. The molar masses get larger for each of the gasses. That means that the helium root mean square speed is going to be the largest since it has the smallest smaller mass and these two terms are inversely proportional. So this is going to be the greatest and since argon has a smaller molar mass than xenon, that means argon will have a greater root mean square speed. So after we have plugged in our inequality symbols here, we can see that we get an answer choice of a. Thank you all so much for watching hope. This video helped. We will see you all in the next one.