The compressibility factor for 1 mole of a van der Waals gas at 0oC and 100 atm pressure is found to be 0.5. Assuming that the volume of a gas molecule is negligible, calculate the van der Waals constant, a.

The rms speed of an ideal gas at 27°C is 0.3 ms–1 . Its rms speed at 927°C (in ms–1) is