Which of the following statements is true? which of the following statements is true? a) the smaller a gas particle, the slower it will effuse. b) at a given temperature, lighter gas particles travel more slowly than heavier gas particles. c) at low temperatures, intermolecular forces become important and the pressure of a gas will be higher than predicted by the ideal gas law. d) the higher the temperature, the higher the average kinetic energy of the sample. e) none of the above statements is true.