Discussion:
Unknown Gases: Hydrohalic Acids
You have two unknown gases that are hydrohalic acids (i.e., HF, HCl, HBr, and HI). You don't know which is which. So, you decided to do an experiment. This experiment involves a ten meter, exactly, long glass cylinder that can be evacuated. At one end of the glass cylinder is a compartment, which has a small hole so that the gases can escape, into which the unknown gases can be put. At the other end is a detector that can detect when the gas molecules reach that point. You place the gases, at 25 EC, in to the compartment, the cylinder is evacuated, and the hole is opened. The detector indicates that one gas reaches it in 0.032984 sec and the second gas reaches the detector in 0.041472 sec. What two hydrohalic acids are these?
Hint:
KE = ½mv2, but it also equals 3/2kT, where k is Boltzmann's constant, which, actually equals the gas constant, R, divided by Avogadro's number (NA). Fully justify your answer.