One mole of an element or substance, a) has a mass of 1 g. b) has a mass of 1 molar mass. c) has a number of atoms or molecules equal to half Avogadro's number NA. d) has a number of atoms or molecules equal to atomic number Z. In ideal gas, a) molecules rotate or vibrate. b) the collision between molecules is inelastic. c) there is no clear relation between pressure, volume, and absolute temperature. d) there is a clear relation between pressure, volume, and absolute temperature. In Boyl's law. a) The absolute temperature is not constant. b) The pressure of the gas is inversely proportional to the volume. c) The pressure of the gas is directly proportional to the absolute temperature. d) The volume of the gas is directly proportional to the absolute temperature.