Calculate the collision frequency for (a) a molecule in a sample of oxygen at 1.00 atm pressure and 25°C, and (b) a molecule of hydrogen in a region of interstellar space where the number density is 1.0 × 1010 molecules per cubic meter and the temperature is 30 K. Take the diameter of O2 to be 2.92 × 10-10 m and that of H2 to be 2.34 × 10-10 m.