19. You have a certain mass of helium gas (He) in a rigid steel container. You add the same mass of neon gas (Ne) to this container. Which of the following best describes what happens? Assume the temperature is constant. A) The pressure in the container doubles. B) The pressure in the container increases but does not double. C) The pressure in the container more than doubles. D) The volume of the container doubles. E) The volume of the container more than doubles.