Final answer:
The question involves calculating the total pressure in a piston-type vessel containing two liquid components using Raoult's law, Ideal Gas Law, and Dalton's Law of Partial Pressures under isothermal conditions to determine pressure and composition at two key moments.
Step-by-step explanation:
Answering a Chemistry Question on Gas Mixtures
The question relates to the behavior of a gas mixture within a piston-type vessel with two different liquid components, A and B, each with a given initial partial vapor pressure. The scenario involves isothermal conditions, and the student is asked to determine the total pressure at which the first bubble is formed and its composition, as well as the pressure at which the last drop of liquid remains.
For part (a), when the first bubble is formed, the total pressure of the system is the sum of the partial pressures of components A and B. Raoult's law allows us to calculate the partial pressures of each component based on their initial partial pressures (PA0 and PB0) and their mole fractions.
For part (b), when the last drop of liquid remains, the vapor pressures of A and B would not change; however, the composition of the vapor phase will depend on their initial vapor pressures and the extent to which they have been consumed. At this point, the pressure will be the sum of the partial pressures of A and B, assuming the temperature remains constant.