1. The problem statement, all variables and given/known data Heat is added until the rms speed of a helium atom has increased 50%. Find new pressure. (Not all parameters given.) 2. Relevant equations rms = (3kT/m)1/2 mass of molecule = mass of mole/NA Then, mass of helium molecule is 6.6x10-26kg 3. The attempt at a solution Question: Is rms speed of a helium molecule the same as the rms speed of an atom. Yes, because the atoms make up the molecule? No, helium is diatomic (right?) and so that has to be taken into account??